ob_basic_session_info.cpp

/**
 * Copyright (c) 2021 OceanBase
 * OceanBase CE is licensed under Mulan PubL v2.
 * You can use this software according to the terms and conditions of the Mulan PubL v2.
 * You may obtain a copy of Mulan PubL v2 at:
 *          http://license.coscl.org.cn/MulanPubL-2.0
 * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
 * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
 * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
 * See the Mulan PubL v2 for more details.
 */

#define USING_LOG_PREFIX SQL_SESSION

#include "sql/session/ob_basic_session_info.h"

#include "lib/string/ob_sql_string.h"
#include "lib/timezone/ob_oracle_format_models.h"
#include "common/sql_mode/ob_sql_mode_utils.h"
#include "common/ob_smart_call.h"
#include "share/config/ob_server_config.h"
#include "share/schema/ob_schema_getter_guard.h"
#include "share/schema/ob_sys_variable_mgr.h"
#include "sql/engine/ob_exec_context.h"
#include "sql/plan_cache/ob_plan_cache_util.h"
#include "sql/plan_cache/ob_prepare_stmt_struct.h"
#include "sql/ob_sql_trans_util.h"
#include "observer/ob_server_struct.h"
#include "sql/engine/ob_physical_plan.h"
#include "storage/tx/wrs/ob_weak_read_util.h"       //ObWeakReadUtil
#include "storage/tx/ob_trans_service.h"
#include "observer/omt/ob_tenant_timezone_mgr.h"
#include "observer/omt/ob_tenant_config_mgr.h"
#include "share/ob_label_security.h"
#include "share/system_variable/ob_nls_system_variable.h"
#include "share/rc/ob_tenant_base.h"
#include "pl/sys_package/ob_dbms_sql.h"
#include "pl/ob_pl_package_state.h"

using namespace oceanbase::common;
using namespace oceanbase::share;
using namespace oceanbase::share::schema;
using namespace oceanbase::transaction;
using oceanbase::omt::ObTenantConfigMgr;

namespace oceanbase
{
namespace sql
{

ObBasicSessionInfo::SysVarsCacheData ObBasicSessionInfo::SysVarsCache::base_data_;

ObBasicSessionInfo::ObBasicSessionInfo()
    : query_mutex_(),
      thread_data_mutex_(),
      is_valid_(true),
      is_deserialized_(false),
      tenant_id_(OB_INVALID_ID),
      effective_tenant_id_(OB_INVALID_ID),
      rpc_tenant_id_(0),
      is_changed_to_temp_tenant_(false),
      user_id_(OB_INVALID_ID),
      client_version_(),
      driver_version_(),
      sessid_(0),
      master_sessid_(INVALID_SESSID),
      proxy_sessid_(VALID_PROXY_SESSID),
      variables_last_modify_time_(0),
      global_vars_version_(0),
      sys_var_base_version_(OB_INVALID_VERSION),
      tx_desc_(NULL),
      tx_result_(),
      read_snapshot_version_(-1),
      xid_(),
      associated_xa_(false),
      sess_bt_buff_pos_(0),
      sess_ref_cnt_(0),
      sess_ref_seq_(0),
      block_allocator_(SMALL_BLOCK_SIZE, common::OB_MALLOC_NORMAL_BLOCK_SIZE - 32,
                       //这里减32是为了适配ObMalloc对齐规则, 防止超8k的内存分配
                       ObMalloc(ObModIds::OB_SQL_SESSION_SBLOCK)),
      ps_session_info_allocator_(sizeof(ObPsSessionInfo), common::OB_MALLOC_NORMAL_BLOCK_SIZE - 32,
                                 //这里减32是为了适配ObMalloc对齐规则, 防止超8k的内存分配
                                 ObMalloc("PsSessionInfo")),
      cursor_info_allocator_(sizeof(pl::ObDbmsCursorInfo), common::OB_MALLOC_NORMAL_BLOCK_SIZE - 32,
                             ObMalloc("SessCursorInfo")),
      package_info_allocator_(sizeof(pl::ObPLPackageState), common::OB_MALLOC_NORMAL_BLOCK_SIZE - 32,
                              ObMalloc("SessPackageInfo")),
      name_pool_(ObModIds::OB_SQL_SESSION, OB_MALLOC_NORMAL_BLOCK_SIZE),
      trans_flags_(),
      sql_scope_flags_(),
      base_sys_var_alloc_(ObModIds::OB_SQL_SESSION, OB_MALLOC_NORMAL_BLOCK_SIZE),
      inc_sys_var_alloc_(ObModIds::OB_SQL_SESSION, OB_MALLOC_NORMAL_BLOCK_SIZE),
      bucket_allocator_wrapper_(&block_allocator_),
      user_var_val_map_(SMALL_BLOCK_SIZE, ObWrapperAllocator(&block_allocator_)),
      influence_plan_var_indexs_(),
      is_first_gen_(true),
      is_first_gen_config_(true),
      sys_var_fac_(),
      next_frag_mem_point_(OB_MALLOC_NORMAL_BLOCK_SIZE), // 8KB
      sys_vars_encode_max_size_(0),
      consistency_level_(INVALID_CONSISTENCY),
      tz_info_wrap_(),
      next_tx_read_only_(-1),
      next_tx_isolation_(transaction::ObTxIsolationLevel::INVALID),
      log_id_level_map_valid_(false),
      cur_phy_plan_(NULL),
      plan_id_(0),
      capability_(),
      proxy_capability_(),
      client_mode_(OB_MIN_CLIENT_MODE),
      changed_sys_vars_(),
      changed_user_vars_(),
      changed_var_pool_(ObModIds::OB_SQL_SESSION, OB_MALLOC_NORMAL_BLOCK_SIZE),
      extra_info_allocator_(ObModIds::OB_SQL_SESSION, OB_MALLOC_NORMAL_BLOCK_SIZE),
      is_database_changed_(false),
      feedback_manager_(),
      trans_spec_status_(TRANS_SPEC_NOT_SET),
      debug_sync_actions_(),
      partition_hit_(),
      magic_num_(0x13572468),
      current_execution_id_(-1),
      database_id_(OB_INVALID_ID),
      retry_info_(),
      last_query_trace_id_(),
      nested_count_(-1),
      inf_pc_configs_(),
      curr_trans_last_stmt_end_time_(0),
      check_sys_variable_(true),
      is_foreign_key_cascade_(false),
      is_foreign_key_check_exist_(false),
      acquire_from_pool_(false),
      release_to_pool_(true),
      is_tenant_killed_(0),
      reused_count_(0),
      first_need_txn_stmt_type_(stmt::T_NONE),
      exec_min_cluster_version_(GET_MIN_CLUSTER_VERSION()),
      stmt_type_(stmt::T_NONE),
      labels_(),
      thread_id_(0),
      is_password_expired_(false),
      process_query_time_(0)
{
  thread_data_.reset();
  MEMSET(sys_vars_, 0, sizeof(sys_vars_));
  log_id_level_map_.reset_level();
  CHAR_CARRAY_INIT(tenant_);
  CHAR_CARRAY_INIT(effective_tenant_);
  CHAR_CARRAY_INIT(trace_id_buff_);
  ssl_cipher_buff_[0] = '\0';
  sess_bt_buff_[0] = '\0';
}

ObBasicSessionInfo::~ObBasicSessionInfo()
{
  destroy();
}

bool ObBasicSessionInfo::is_server_status_in_transaction() const
{
  bool can_free_route = tx_desc_ == NULL || tx_desc_->can_free_route();
  bool result = !can_free_route;
  /*
   * if autocommit is OFF and user has issued query which need transaction protection
   * the switch 'ob_proxy_readonly_transaction_routing_policy' control whether
   * client should assume current session is inner transaction:
   * - in transaction if switch ON
   * - out of transaction if switch is OFF
   */
  bool auto_commit = get_local_autocommit();
  if (can_free_route
      && !auto_commit /*  autocommit = OFF */
      && get_first_need_txn_stmt_type() != stmt::StmtType::T_NONE /* has issued transactional query */) {
    omt::ObTenantConfigGuard tenant_config(TENANT_CONF(get_effective_tenant_id()));
    result = tenant_config->ob_proxy_readonly_transaction_routing_policy; /* switch is ON */
  }
  LOG_TRACE("decide flag: server in transaction", K(can_free_route),
            K(result), KPC(tx_desc_), K(auto_commit), K(get_first_need_txn_stmt_type()));
  return result;
}

//for test
int ObBasicSessionInfo::test_init(uint32_t sessid, uint64_t proxy_sessid,
                             common::ObIAllocator *bucket_allocator)
{
  int ret = OB_SUCCESS;
  if (NULL != bucket_allocator) {
    bucket_allocator_wrapper_.set_alloc(bucket_allocator);
  }

  ret = user_var_val_map_.init(1024 * 1024 * 2,
                               256, // # of user variables
                               (NULL == bucket_allocator ? NULL : &bucket_allocator_wrapper_));
  if (OB_FAIL(ret)) {
    LOG_WARN("fail to init user_var_val_map", K(ret));
  } else if (OB_FAIL(load_default_configs_in_pc())) {
    LOG_WARN("fail to load default config influence plan cache", K(ret));
  } else if (OB_FAIL(debug_sync_actions_.init(SMALL_BLOCK_SIZE, bucket_allocator_wrapper_))) {
    LOG_WARN("fail to init debug sync actions", K(ret));
  } else if (OB_FAIL(set_session_state(SESSION_INIT))) {
    LOG_WARN("fail to set session stat", K(ret));
  } else if (OB_FAIL(set_time_zone(ObString("+8:00"), is_oracle_compatible(),
                                   true/* check_timezone_valid */))) {
    LOG_WARN("fail to set time zone", K(ret));
  } else {
    // tz_info_wrap_.set_tz_info_map(GCTX.tz_info_mgr_->get_tz_info_map());
    sessid_ = sessid;
    proxy_sessid_ = proxy_sessid;
  }
  return ret;
}

bool ObBasicSessionInfo::is_use_inner_allocator() const
{
  return bucket_allocator_wrapper_.get_alloc() == &block_allocator_;
}

int ObBasicSessionInfo::init(uint32_t sessid, uint64_t proxy_sessid,
                             common::ObIAllocator *bucket_allocator, const ObTZInfoMap *tz_info)
{
  int ret = OB_SUCCESS;
  ObWrapperAllocator *user_var_allocator_wrapper = NULL;
  if (is_acquire_from_pool()) {
    reused_count_++;
    if (OB_NOT_NULL(bucket_allocator) || !is_use_inner_allocator()) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("session from pool must use inner allocator", K(ret));
    }
  } else {
    if (NULL != bucket_allocator) {
      bucket_allocator_wrapper_.set_alloc(bucket_allocator);
      user_var_allocator_wrapper = &bucket_allocator_wrapper_;
    }
  }
  if (OB_FAIL(ret)) {
  } else if (!is_acquire_from_pool() &&
             OB_FAIL(user_var_val_map_.init(1024 * 1024 * 2, 256, user_var_allocator_wrapper))) {
    LOG_WARN("fail to init user_var_val_map", K(ret));
  } else if (!is_acquire_from_pool() &&
             OB_FAIL(debug_sync_actions_.init(SMALL_BLOCK_SIZE, bucket_allocator_wrapper_))) {
    LOG_WARN("fail to init debug sync actions", K(ret));
  } else if (OB_FAIL(set_session_state(SESSION_INIT))) {
    LOG_WARN("fail to set session stat", K(ret));
/*  } else if (FALSE_IT(tx_result_.set_trans_desc(&trans_desc_))) { */
  } else {
    sessid_ = sessid;
    proxy_sessid_ = proxy_sessid;
    uint64_t tenant_id = tenant_id_;
    if (OB_ISNULL(tz_info)) {
      ObTZMapWrap tz_map_wrap;
      if (OB_FAIL(OTTZ_MGR.get_tenant_tz(tenant_id, tz_map_wrap))) {
        LOG_WARN("get tenant timezone map failed", K(ret));
      } else {
        tz_info_wrap_.set_tz_info_map(tz_map_wrap.get_tz_map());
      }
    } else {
      tz_info_wrap_.set_tz_info_map(tz_info);
    }
  }
  return ret;
}

void ObBasicSessionInfo::destroy()
{
  if (magic_num_ != 0x13572468) {
    LOG_ERROR("ObBasicSessionInfo may be double free!!!", K(magic_num_));
  }
  if (OB_NOT_NULL(tx_desc_)) {
    LOG_ERROR("tx_desc != NULL", KPC(this), KPC_(tx_desc));
  }
  tx_desc_ = NULL;
  tx_result_.reset();
  xid_.reset();
  associated_xa_ = false;
  magic_num_ = 0x86427531;
  if (thread_data_.cur_query_ != nullptr) {
    ob_free(thread_data_.cur_query_);
    thread_data_.cur_query_ = nullptr;
    thread_data_.cur_query_buf_len_ = 0;
  }
  total_stmt_tables_.reset();
  cur_stmt_tables_.reset();
}

void ObBasicSessionInfo::clean_status()
{
  trans_flags_.reset();
  sql_scope_flags_.reset();
  trans_spec_status_ = TRANS_SPEC_NOT_SET;
  if (OB_NOT_NULL(tx_desc_)) {
    int ret = OB_SUCCESS;
    MAKE_TENANT_SWITCH_SCOPE_GUARD(guard);
    if (OB_SUCC(guard.switch_to(tx_desc_->get_tenant_id(), false))) {
      MTL(transaction::ObTransService*)->release_tx(*tx_desc_);
    }
    tx_desc_ = NULL;
  }
  xid_.reset();
  associated_xa_ = false;
  set_valid(true);
  thread_data_.cur_query_start_time_ = 0;
  thread_data_.cur_query_len_ = 0;
  thread_data_.last_active_time_ = ObTimeUtility::current_time();
  reset_session_changed_info();
}

void ObBasicSessionInfo::reset(bool skip_sys_var)
{
  set_valid(false);

  if (OB_NOT_NULL(tx_desc_)) {
    int ret = OB_SUCCESS;
    MAKE_TENANT_SWITCH_SCOPE_GUARD(guard);
    if (OB_SUCC(guard.switch_to(tx_desc_->get_tenant_id(), false))) {
      MTL(transaction::ObTransService*)->release_tx(*tx_desc_);
    }
    tx_desc_ = NULL;
  }
  xid_.reset();
  associated_xa_ = false;
  is_deserialized_ = false;
  CHAR_CARRAY_INIT(tenant_);
  tenant_id_ = OB_INVALID_ID;
  CHAR_CARRAY_INIT(effective_tenant_);
  effective_tenant_id_ = OB_INVALID_ID;
  is_changed_to_temp_tenant_ = false;
  user_id_ = OB_INVALID_ID;
  client_version_.reset();
  driver_version_.reset();
  sessid_ = 0;
  master_sessid_ = INVALID_SESSID;
  proxy_sessid_ = VALID_PROXY_SESSID;
  variables_last_modify_time_ = 0;
  global_vars_version_ = 0;

  tx_result_.reset();
  total_stmt_tables_.reset();
  cur_stmt_tables_.reset();
  // reset() of user_var_val_map_ and debug_sync_actions_ will keep some memory
  // allocated from block_allocator_ / bucket_allocator_wrapper_, so we skip
  // reset() of block_allocator_ and bucket_allocator_wrapper_.
//block_allocator_.reset();
  ps_session_info_allocator_.reset();
  cursor_info_allocator_.reset();
  package_info_allocator_.reset();
  trans_flags_.reset();
  sql_scope_flags_.reset();
//bucket_allocator_wrapper_.reset();
  user_var_val_map_.reuse();
  if (!skip_sys_var) {
    memset(sys_vars_, 0, sizeof(sys_vars_));
    influence_plan_var_indexs_.reset();
  } else {
    const SysVarIds &all_sys_var_ids = sys_var_inc_info_.get_all_sys_var_ids();
    for (int i = 0; i < all_sys_var_ids.count(); i++) {
      int ret = OB_SUCCESS;
      int64_t store_idx = -1;
      ObSysVarClassType sys_var_id = all_sys_var_ids.at(i);
      OZ (ObSysVarFactory::calc_sys_var_store_idx(sys_var_id, store_idx));
      OV (0 <= store_idx && store_idx < ObSysVarFactory::ALL_SYS_VARS_COUNT);
      OV (OB_NOT_NULL(sys_vars_[store_idx]));
      OX (sys_vars_[store_idx]->clean_inc_value());
    }
    // I don't see any reason why we should reset timezone
    // reset_timezone();
  }
  sys_var_inc_info_.reset();
  sys_var_in_pc_str_.reset();
  config_in_pc_str_.reset();
  is_first_gen_ = true;
  is_first_gen_config_ = true;
  CHAR_CARRAY_INIT(trace_id_buff_);
//consistency_level_ = INVALID_CONSISTENCY;
  next_tx_read_only_ = -1;
  next_tx_isolation_ = transaction::ObTxIsolationLevel::INVALID;
  log_id_level_map_valid_ = false;
  log_id_level_map_.reset_level();
  cur_phy_plan_ = NULL;
  plan_id_ = 0;
  capability_.capability_ = 0;
  proxy_capability_.capability_ = 0;
  client_mode_ = OB_MIN_CLIENT_MODE;
  reset_session_changed_info();
  extra_info_allocator_.reset();
  trans_spec_status_ = TRANS_SPEC_NOT_SET;
  debug_sync_actions_.reset();
  partition_hit_.reset();
//magic_num_ = 0x86427531;
  current_execution_id_ = -1;
  last_trace_id_.reset();
  curr_trace_id_.reset();
  app_trace_id_.reset();
  database_id_ = OB_INVALID_ID;
  retry_info_.reset();
  last_query_trace_id_.reset();
  thread_data_.reset();
  nested_count_ = -1;
  // session 缓存的场景下，只保留 base 值，清理 inc 值
  // 去掉 sys var schema version 后，base 值即为 hardcode 值
  if (!skip_sys_var) {
    sys_vars_cache_.reset();
    sys_var_base_version_ = OB_INVALID_VERSION;
  } else {
    sys_vars_cache_.clean_inc();
    sys_var_base_version_ = CACHED_SYS_VAR_VERSION;
  }
  curr_trans_last_stmt_end_time_ = 0;
  read_snapshot_version_ = OB_INVALID_VERSION;
  check_sys_variable_ = true;
  is_foreign_key_cascade_ = false;
  is_foreign_key_check_exist_ = false;
  acquire_from_pool_ = false;
  // 不要重置release_to_pool_，原因见属性声明位置的注释。
  is_tenant_killed_ = 0;
  first_need_txn_stmt_type_ = stmt::T_NONE;
  exec_min_cluster_version_ = GET_MIN_CLUSTER_VERSION();
  labels_.reuse();
  thread_id_ = 0;
  is_password_expired_ = false;
  process_query_time_ = 0;
  sess_bt_buff_pos_ = 0;
  ATOMIC_SET(&sess_ref_cnt_ , 0);
  // 最后再重置所有allocator
  // 否则thread_data_.user_name_之类的属性会有野指针，在session_mgr的foreach接口遍历时可能core掉。
  name_pool_.reset();
  inc_sys_var_alloc_.reset();
  if (!skip_sys_var) {
    base_sys_var_alloc_.reset();
    sys_var_fac_.destroy();
  }
  client_identifier_.reset();
}

int ObBasicSessionInfo::reset_timezone()
{
  int ret = OB_SUCCESS;
  ObObj tmp_obj1;
  if (OB_FAIL(get_sys_variable(SYS_VAR_TIME_ZONE, tmp_obj1))) {
    LOG_WARN("get sys var failed", K(ret));
  } else if (OB_FAIL(process_session_time_zone_value(tmp_obj1, false))) {
    LOG_WARN("set time zone failed", K(ret));
  }

  ObObj tmp_obj2;
  if (OB_FAIL(get_sys_variable(SYS_VAR_ERROR_ON_OVERLAP_TIME, tmp_obj2))) {
    LOG_WARN("get sys var failed", K(ret));
  } else if (OB_FAIL(process_session_overlap_time_value(tmp_obj2))) {
    LOG_WARN("process session overlap time value failed", K(ret), K(tmp_obj2));
  }
  return ret;
}

int ObBasicSessionInfo::init_tenant(const ObString &tenant_name, const uint64_t tenant_id)
{
  int ret = OB_SUCCESS;
  if (OB_UNLIKELY(!is_valid_tenant_id(tenant_id))) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid tenant id", K(tenant_id), K(ret));
  } else if (tenant_name.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("tenant name is empty", K(tenant_name), K(ret));
  } else if (tenant_name.length() > OB_MAX_TENANT_NAME_LENGTH) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("tenant name too long", K(tenant_name), K(ret));
  } else if (OB_FAIL(ob_cstrcopy(tenant_, sizeof(tenant_), tenant_name))) {
    LOG_WARN("failed to copy tenant name", K(tenant_name), K(ret));
  } else if (OB_FAIL(ob_cstrcopy(effective_tenant_, sizeof(effective_tenant_), tenant_name))) {
    LOG_WARN("failed to copy effective tenant name", K(tenant_name), K(ret));
  } else {
    ObTZMapWrap tz_map_wrap;
    if (OB_FAIL(OTTZ_MGR.get_tenant_tz(tenant_id, tz_map_wrap))) {
      LOG_WARN("get tenant timezone map failed", K(ret));
    } else {
      tz_info_wrap_.set_tz_info_map(tz_map_wrap.get_tz_map());
      tenant_id_ = tenant_id;
      effective_tenant_id_ = tenant_id;
      LOG_DEBUG("init session tenant", K(tenant_name), K(tenant_id));
    }
  }
  return ret;
}

int ObBasicSessionInfo::set_tenant(const common::ObString &tenant_name, const uint64_t tenant_id)
{
  int ret = OB_SUCCESS;
  if (!is_valid_tenant_id(tenant_id)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid tenant id", K(tenant_id), K(ret));
  } else if (tenant_name.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("tenant name is empty", K(tenant_name), K(ret));
  } else if (tenant_name.length() > OB_MAX_TENANT_NAME_LENGTH) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("tenant name too long", K(tenant_name), K(ret));
  } else if (OB_FAIL(ob_cstrcopy(tenant_, sizeof(tenant_), tenant_name))) {
    LOG_WARN("tenant name too long", K(tenant_name));
  } else {
    tenant_id_ = tenant_id;
    LOG_TRACE("set tenant", K(tenant_name), K(tenant_id));
  }
  return ret;
}

int ObBasicSessionInfo::set_tenant(const common::ObString &tenant_name,
                                   const uint64_t tenant_id,
                                   char *ori_tenant_name,
                                   const uint64_t length,
                                   uint64_t &ori_tenant_id)
{
  int ret = OB_SUCCESS;
  if (!is_valid_tenant_id(tenant_id)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid tenant id", K(tenant_id), K(ret));
  } else if (OB_ISNULL(ori_tenant_name)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("ori_tenant_name is NULL", K(ret));
  } else if (length < OB_MAX_TENANT_NAME_LENGTH + 1) {
    ret = OB_INVALID_ARGUMENT_FOR_LENGTH;
    LOG_WARN("tenant_name length is not enough ");
  } else if (tenant_name.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("tenant name is empty", K(tenant_name), K(ret));
  } else if (tenant_name.length() > OB_MAX_TENANT_NAME_LENGTH) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("tenant name too long", K(tenant_name), K(ret));
  } else if (OB_FAIL(ob_cstrcopy(ori_tenant_name, length, tenant_, strlen(tenant_)))) {
    LOG_ERROR("tenant_name is longer than ori_tenant_name", K(length), K(strlen(tenant_)));
  } else if (OB_FAIL(ob_cstrcopy(tenant_, sizeof(tenant_), tenant_name))) {
    LOG_ERROR("tenant name too long", K(tenant_name));
  } else {
    ori_tenant_id = tenant_id_;
    tenant_id_ = tenant_id;
  }
  return ret;
}

int ObBasicSessionInfo::switch_tenant(uint64_t effective_tenant_id)
{
  int ret = OB_SUCCESS;
  if (OB_SYS_TENANT_ID != tenant_id_) {
    ret = OB_NOT_SUPPORTED;
    LOG_USER_ERROR(OB_NOT_SUPPORTED, "switching tenant from a non-sys tenant");
    LOG_WARN("only support sys tenant switch tenant", K(ret), K(tenant_id_), K(effective_tenant_id_));
  } else if (effective_tenant_id <= 0) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid tenant_id", K(ret), K(effective_tenant_id));
  } else if (OB_NOT_NULL(tx_desc_) && effective_tenant_id != effective_tenant_id_) {
    if (!tx_desc_->can_free_route()) {
      ret = OB_NOT_SUPPORTED;
      // only inner-SQL goes switch_tenant and may fall into such state
      // print out error to easy trouble-shot
      LOG_USER_ERROR(OB_NOT_SUPPORTED, 
                  "try to switch to another tenant without commit/rollback in a transaction");
      LOG_ERROR("try to switch another tenant while session has active txn,"
                " you must commit/rollback first", K(ret),
                "current_effective_tenant_id", effective_tenant_id_,
                "target_effective_tenant_id", effective_tenant_id,
                KPC(tx_desc_), KPC(this));
    } else if (OB_FAIL(ObSqlTransControl::reset_session_tx_state(this))) {
      LOG_WARN("reset session tx state fail", K(ret), KPC(this));
    }
  }
  if (OB_SUCC(ret)) {
#ifndef NDEBUG
    if (effective_tenant_id_ != effective_tenant_id) {
      LOG_INFO("switch tenant",
               "target_effective_tenant_id", effective_tenant_id,
               "current_effective_tenant_id", effective_tenant_id_,
               "priv_tenant_id", tenant_id_,
               K(lbt()));
    }
#endif
    effective_tenant_id_ = effective_tenant_id;
  }
  return ret;
}

const common::ObString ObBasicSessionInfo::get_tenant_name() const
{
  return ObString::make_string(tenant_);
}

const common::ObString ObBasicSessionInfo::get_effective_tenant_name() const
{
  return ObString::make_string(effective_tenant_);
}

int ObBasicSessionInfo::set_user(const ObString &user_name, const ObString &host_name, const uint64_t user_id)
{
  int ret = OB_SUCCESS;
  if (OB_UNLIKELY(user_name.length() > common::OB_MAX_USER_NAME_LENGTH)
      || OB_UNLIKELY(host_name.length() > common::OB_MAX_HOST_NAME_LENGTH)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("name length invalid_", K(user_name), K(host_name), K(ret));
  } else {
    char tmp_buf[common::OB_MAX_USER_NAME_LENGTH + common::OB_MAX_HOST_NAME_LENGTH + 2] = {};
    snprintf(tmp_buf, sizeof(tmp_buf), "%.*s@%.*s", user_name.length(), user_name.ptr(),
                                                    host_name.length(), host_name.ptr());
    ObString tmp_string(tmp_buf);
    LockGuard lock_guard(thread_data_mutex_);
    if (OB_FAIL(name_pool_.write_string(user_name, &thread_data_.user_name_))) {
      LOG_WARN("fail to write username to string_buf_", K(user_name), K(ret));
    } else if (OB_FAIL(name_pool_.write_string(host_name, &thread_data_.host_name_))) {
      LOG_WARN("fail to write hostname to string_buf_", K(host_name), K(ret));
    } else if (OB_FAIL(name_pool_.write_string(tmp_string, &thread_data_.user_at_host_name_))) {
      LOG_WARN("fail to write user_at_host_name to string_buf_", K(tmp_string), K(ret));
    } else {
      user_id_ = user_id;
    }
  }
  return ret;
}

int ObBasicSessionInfo::set_real_client_ip(const common::ObString &client_ip)
{
  int ret = OB_SUCCESS;
  char tmp_buf[common::OB_MAX_USER_NAME_LENGTH + common::OB_MAX_HOST_NAME_LENGTH + 2] = {};
  snprintf(tmp_buf, sizeof(tmp_buf), "%.*s@%.*s", thread_data_.user_name_.length(),
                                                  thread_data_.user_name_.ptr(),
                                                  client_ip.length(),
                                                  client_ip.ptr());
  ObString tmp_string(tmp_buf);
  LockGuard lock_guard(thread_data_mutex_);
  if (OB_FAIL(name_pool_.write_string(client_ip, &thread_data_.client_ip_))) {
    LOG_WARN("fail to write client_ip to string_buf_", K(client_ip), K(ret));
  } else if (OB_FAIL(name_pool_.write_string(tmp_string, &thread_data_.user_at_client_ip_))) {
    LOG_WARN("fail to write user_at_host_name to string_buf_", K(tmp_string), K(ret));
  } else {
    thread_data_.user_client_addr_.set_ip_addr(client_ip, 0);
  }
  return ret;
}

int ObBasicSessionInfo::set_client_identifier(const common::ObString &client_identifier)
{
  int ret = OB_SUCCESS;
  int max_size = OB_MAX_CONTEXT_CLIENT_IDENTIFIER_LENGTH_IN_SESSION;
  if (OB_FAIL(init_client_identifier())) {
    LOG_WARN("failed to init client identifier", K(ret));
  } else {
    //reset curr identifier
    client_identifier_.set_length(0);
    //write new string
    int64_t write_len = std::min(client_identifier_.size(), client_identifier.length());
    if (write_len != client_identifier_.write(client_identifier.ptr(), write_len)) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("failed to write client identifier", K(ret), K(client_identifier_), K(write_len));
    }
  }
  return ret;
}

int ObBasicSessionInfo::init_client_identifier()
{
  int ret = OB_SUCCESS;
  int max_size = OB_MAX_CONTEXT_CLIENT_IDENTIFIER_LENGTH_IN_SESSION;
  if (OB_ISNULL(client_identifier_.ptr())) {
    char *ptr = nullptr;
    if (OB_ISNULL(ptr = static_cast<char *> (get_session_allocator().alloc(max_size)))) {
      ret = OB_ALLOCATE_MEMORY_FAILED;
      LOG_WARN("failed to alloc mem for client identifier", K(ret));
    } else {
      client_identifier_.assign_buffer(ptr, max_size);
    }
  } else if (max_size != client_identifier_.size()) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("get wrong client identifier", K(ret), K(client_identifier_.size()));
  }
  return ret;
}

int ObBasicSessionInfo::check_and_init_retry_info(const ObCurTraceId::TraceId &cur_trace_id,
                                                  const ObString &sql)
{
  int ret = OB_SUCCESS;
  // 下面这段判断影响太大，害怕出问题，所以打了ERROR之后还是继续执行，仅仅影响retry info，还是可以正常执行的
  if (last_query_trace_id_.equals(cur_trace_id)) { // 是重试query的包
    if (OB_UNLIKELY(!retry_info_.is_inited())) {
      LOG_ERROR("is retry packet, but retry info is not inited, will init it",
                K(last_query_trace_id_), K(cur_trace_id), K(retry_info_), K(get_sessid()), K(sql));
      if (OB_FAIL(retry_info_.init())) {
        LOG_WARN("fail to init retry info", K(ret), K(retry_info_), K(sql));
      }
    }
  } else {
    //@TODO: 不是重试query的包，在正常语句结束的时候，不做清空重试信息逻辑，后续这个地方会做成按需初始化,
    //减少正常语句的执行开销，所以如果是上一条语句初始化了重试信息，这里直接清空掉，
    //因为对于异步执行而言，在控制端线程结束的时候判断无法判断其重试状态，所以不能做清空重试信息操作
    if (OB_UNLIKELY(retry_info_.is_inited())) {
      retry_info_.reset();
    }
    // 不是重试query的包都要init retry info
    if (OB_FAIL(retry_info_.init())) {
      LOG_WARN("fail to init retry info", K(ret), K(retry_info_), K(sql));
    } else {
      last_query_trace_id_.set(cur_trace_id);
    }
  }
  return ret;
}

const ObLogIdLevelMap *ObBasicSessionInfo::get_log_id_level_map() const
{
  return (log_id_level_map_valid_ ? (&log_id_level_map_) : NULL);
}

int ObBasicSessionInfo::set_client_version(const ObString &client_version)
{
  int ret = OB_SUCCESS;
  if (client_version.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("client version is empty", K(client_version), K(ret));
  } else if (OB_FAIL(name_pool_.write_string(client_version, &client_version_))) {
    LOG_WARN("failed to write client_version to string_buf_", K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::set_driver_version(const ObString &driver_version)
{
  int ret = OB_SUCCESS;
  if (driver_version.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("driver version is empty", K(driver_version), K(ret));
  } else if (OB_FAIL(name_pool_.write_string(driver_version, &driver_version_))) {
    LOG_WARN("failed to write driver_version to string_buf_", K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::set_default_database(const ObString &database_name,
                                             const ObCollationType coll_type/*= CS_TYPE_INVALID */)
{
  int ret = OB_SUCCESS;
  if (database_name.length() > OB_MAX_DATABASE_NAME_LENGTH * OB_MAX_CHAR_LEN) {
    ret = OB_INVALID_ARGUMENT_FOR_LENGTH;
    LOG_WARN("invalid length for database_name", K(database_name), K(ret));
  } else {
    if (CS_TYPE_INVALID != coll_type) {
      const int64_t coll_val = static_cast<int64_t>(coll_type);
      if (OB_FAIL(update_sys_variable(SYS_VAR_CHARACTER_SET_DATABASE, coll_val))) {
        LOG_WARN("failed to update variable", K(ret));
      } else if (OB_FAIL(update_sys_variable(SYS_VAR_COLLATION_DATABASE, coll_val))) {
        LOG_WARN("failed to update variable", K(ret));
      } else {}
    }

    if (OB_SUCC(ret)) {
      LockGuard lock_guard(thread_data_mutex_);
      MEMCPY(thread_data_.database_name_, database_name.ptr(), database_name.length());
      thread_data_.database_name_[database_name.length()] = '\0';
      if (is_track_session_info()) {
        is_database_changed_ = true;
      }
    }
  }
  return ret;
}

int ObBasicSessionInfo::update_database_variables(ObSchemaGetterGuard *schema_guard)
{
  int ret = OB_SUCCESS;
  if (OB_ISNULL(schema_guard)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid schema guard is NULL", K(ret));
  } else {
    if ('\0' == thread_data_.database_name_[0]) {
      // no default database
      ObObj val;
      if (OB_FAIL(get_sys_variable(SYS_VAR_CHARACTER_SET_SERVER, val))) {
        LOG_WARN("failed to get sys variable", K(ret));
      } else if (OB_FAIL(update_sys_variable(SYS_VAR_CHARACTER_SET_DATABASE, val))) {
        LOG_WARN("failed to update sys variable", K(ret));
      } else if (OB_FAIL(get_sys_variable(SYS_VAR_COLLATION_SERVER, val))) {
        LOG_WARN("failed to get sys variable", K(ret));
      } else if (OB_FAIL(update_sys_variable(SYS_VAR_COLLATION_DATABASE, val))) {
        LOG_WARN("failed to update sys variable", K(ret));
      } else {}
    } else {
      const share::schema::ObDatabaseSchema *db_schema = NULL;
      ObString db_name(thread_data_.database_name_);
      if (OB_FAIL(schema_guard->get_database_schema(effective_tenant_id_, db_name,
                                                    db_schema))) {
        LOG_WARN("get database schema failed",
                 K(effective_tenant_id_), K(db_name), K(ret));
      } else if (NULL == db_schema) {
        ret = OB_ERR_BAD_DATABASE;
        LOG_WARN("database not exist",
                 K(effective_tenant_id_), K(db_name), K(ret));
        LOG_USER_ERROR(OB_ERR_BAD_DATABASE, db_name.length(), db_name.ptr());
      } else {
        const int64_t db_coll = static_cast<int64_t>(db_schema->get_collation_type());
        if (OB_FAIL(update_sys_variable(SYS_VAR_CHARACTER_SET_DATABASE, db_coll))) {
          LOG_WARN("failed to update sys variable", K(ret));
        } else if (OB_FAIL(update_sys_variable(SYS_VAR_COLLATION_DATABASE, db_coll))) {
          LOG_WARN("failed to update sys variable", K(ret));
        } else {}
      }
    }
  }

  return ret;
}

int ObBasicSessionInfo::update_max_packet_size()
{
  int ret = OB_SUCCESS;
  int64_t max_allowed_pkt = 0;
  int64_t net_buffer_len = 0;
  if (OB_FAIL(get_max_allowed_packet(max_allowed_pkt))) {
    LOG_WARN("fail to get_max_allowed_packet", K(ret));
  } else if (OB_FAIL(get_net_buffer_length(net_buffer_len))) {
    LOG_WARN("fail to get_net_buffer_length", K(ret));
  } else {
    thread_data_.max_packet_size_ = std::max(max_allowed_pkt, net_buffer_len);
  }
  return ret;
}

const ObString ObBasicSessionInfo::get_database_name() const
{
  ObString str_ret;
  str_ret.assign_ptr(const_cast<char*>(thread_data_.database_name_),
                 static_cast<int32_t>(strlen(thread_data_.database_name_)));
  return str_ret;
}

//// FIXME: xiyu
//int ObBasicSessionInfo::get_database_id(
//    ObSchemaGetterGuard *schema_guard,
//    uint64_t &db_id) const
//{
//  int ret = OB_SUCCESS;
//  db_id = OB_INVALID_ID;
//  if (get_database_name().empty()) {
//    //do nothing
//  } else if (OB_UNLIKELY(NULL == schema_guard)) {
//    ret = OB_INVALID_ARGUMENT;
//    LOG_WARN("Schema guard should not be NULL", K(ret));
//  } else if (OB_FAIL(schema_guard->get_database_id(get_effective_tenant_id(), get_database_name(),
//                                                     db_id))) {
//    db_id = OB_INVALID_ID;
//    LOG_WARN("failed to get database id", K(db_id), K(ret));
//  } else { }//do nothing
//  return ret;
//}

////////////////////////////////////////////////////////////////
int ObBasicSessionInfo::get_global_sys_variable(const ObBasicSessionInfo *session,
                                                ObIAllocator &calc_buf,
                                                const ObString &var_name,
                                                ObObj &val)
{
  int ret = OB_SUCCESS;
  if (OB_ISNULL(session)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("session is NULL", K(ret), K(var_name));
  } else {
    //const ObDataTypeCastParams dtc_params(session->get_timezone_info(),
    //                                      session->get_local_nls_formats(),
    //                                      session->get_nls_collation(),
    //                                      session->get_nls_collation_nation());
    ObDataTypeCastParams dtc_params = session->get_dtc_params();
    if (OB_FAIL(get_global_sys_variable(session->get_effective_tenant_id(),
                                        calc_buf, dtc_params, var_name, val))) {
      LOG_WARN("fail to get global sys variable", K(ret), K(var_name));
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_global_sys_variable(const uint64_t actual_tenant_id, // 为了处理租户已经切掉的情况
                                                ObIAllocator &calc_buf,
                                                const ObDataTypeCastParams &dtc_params,
                                                const ObString &var_name,
                                                ObObj &val)
{
  int ret = OB_SUCCESS;
  ObSchemaGetterGuard schema_guard;
  const ObTenantSchema *tenant_schema = NULL;
  const ObSysVarSchema *sysvar_schema = NULL;
  const ObSysVariableSchema *sys_variable_schema = NULL;
  if (OB_UNLIKELY(!is_valid_tenant_id(actual_tenant_id))) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid tenant id", K(actual_tenant_id), K(ret));
  } else if (OB_ISNULL(GCTX.schema_service_)) {
    ret = OB_INVALID_ARGUMENT;
    OB_LOG(WARN,"invalid argument", K(GCTX.schema_service_));
  } else if (OB_FAIL(GCTX.schema_service_->get_tenant_schema_guard(
              actual_tenant_id,
              schema_guard))) {
    ret = OB_SCHEMA_ERROR;
    OB_LOG(WARN,"fail get schema guard", K(ret));
  } else if (OB_FAIL(schema_guard.get_tenant_info(actual_tenant_id, tenant_schema))) {
    LOG_WARN("get tenant info failed", K(ret), K(actual_tenant_id));
  } else if (OB_ISNULL(tenant_schema)) {
    ret = OB_SCHEMA_ERROR;
    LOG_WARN("tenant_schema is NULL", K(ret));
  } else if (OB_FAIL(schema_guard.get_sys_variable_schema(actual_tenant_id, sys_variable_schema))) {
    LOG_WARN("get sys variable schema failed", K(ret));
  } else if (OB_ISNULL(sys_variable_schema)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("sys variable schema is null", K(ret));
  } else if (OB_FAIL(sys_variable_schema->get_sysvar_schema(var_name, sysvar_schema))) {
    ret = OB_ERR_SYS_VARIABLE_UNKNOWN;
    LOG_WARN("failed to get sysvar", K(ret), K(var_name));
  } else if (OB_ISNULL(sysvar_schema)) {
    ret = OB_SCHEMA_ERROR;
    LOG_WARN("tenant_schema is NULL", K(ret));
  } else if (OB_FAIL(sysvar_schema->get_value(&calc_buf, dtc_params, val))) {
    LOG_WARN("failed to get value", K(ret), K(var_name));
  } else if (OB_FAIL(ObBasicSessionInfo::change_value_for_special_sys_var(
                         var_name, val, val))) {
    LOG_ERROR("fail to change value for special sys var", K(ret), K(var_name), K(val));
  } else {
    LOG_DEBUG("get global sysvar", K(var_name), K(val));
  }
  return ret;
}

const ObBasicSysVar *ObBasicSessionInfo::get_sys_var(const int64_t idx) const
{
  const ObBasicSysVar *var = NULL;
  if (idx >= 0 && idx < ObSysVarFactory::ALL_SYS_VARS_COUNT) {
    var = sys_vars_[idx];
  }
  return var;
}

int ObBasicSessionInfo::init_system_variables(const bool print_info_log, const bool is_sys_tenant)
{
  int ret = OB_SUCCESS;
  ObString name;
  ObObj type;
  ObObj value;
  ObObj min_val;
  ObObj max_val;
  ObObjType var_type = ObNullType;
  int64_t var_flag = ObSysVarFlag::NONE;
  int64_t var_amount = ObSysVariables::get_amount();
  ObObj casted_value;
  ObArenaAllocator calc_buf(ObModIds::OB_SQL_SESSION);
  ObCastCtx cast_ctx(&calc_buf, NULL, CM_NONE, ObCharset::get_system_collation());
  for (int64_t i = 0; OB_SUCC(ret) && i < var_amount; ++i) {
    name.assign_ptr(const_cast<char*>(ObSysVariables::get_name(i).ptr()),
                    static_cast<ObString::obstr_size_t>(strlen(ObSysVariables::get_name(i).ptr())));
    bool is_exist = false;
    if (OB_FAIL(sys_variable_exists(name, is_exist))) {
      LOG_WARN("failed to check if sys variable exists", K(name), K(ret));
    } else if (!is_exist) {
      // Note: 如果已经初始化过 base value，则下面的流程不会执行
      var_type = ObSysVariables::get_type(i);
      var_flag = ObSysVariables::get_flags(i);
      value.set_varchar(ObSysVariables::get_value(i));
      value.set_collation_type(ObCharset::get_system_collation());
      min_val.set_varchar(ObSysVariables::get_min(i));
      min_val.set_collation_type(ObCharset::get_system_collation());
      max_val.set_varchar(ObSysVariables::get_max(i));
      max_val.set_collation_type(ObCharset::get_system_collation());
      type.set_type(var_type);
      if(is_sys_tenant) {
        if (OB_FAIL(process_variable_for_tenant(name, value))) {
          LOG_WARN("process system variable for tenant error",  K(name), K(value), K(ret));
        }
      }
      if (OB_SUCC(ret)) {
        if (OB_FAIL(load_sys_variable(calc_buf, name, type, value, min_val, max_val, var_flag, false))) {
          LOG_WARN("fail to load default system variable", K(name), K(ret));
        } else if (OB_NOT_NULL(sys_vars_[i]) &&
                   sys_vars_[i]->is_influence_plan() &&
                   OB_FAIL(influence_plan_var_indexs_.push_back(i))) {
          LOG_WARN("fail to add influence plan sys var", K(name), K(ret));
        } else if(print_info_log) {
          LOG_INFO("load default system variable", name.ptr(), value.get_string().ptr());
        }
      }
    }
  }  // end for
  release_to_pool_ = OB_SUCC(ret);

  if (OB_SUCC(ret)) {
    if (OB_FAIL(gen_sys_var_in_pc_str())) { //将影响plan的系统变量序列化并缓存
      LOG_INFO("fail to generate system variables in pc str");
    } else if (OB_FAIL(gen_configs_in_pc_str())) {
      LOG_INFO("fail to generate system config in pc str");
    } else {
      global_vars_version_ = 0;
    }
  }
  return ret;
}

int ObBasicSessionInfo::update_query_sensitive_system_variable(ObSchemaGetterGuard &schema_guard)
{
  int ret = OB_SUCCESS;
  const ObSysVarSchema *sysvar = NULL;
  int64_t schema_version = -1;
  const ObSimpleSysVariableSchema *sys_variable_schema = NULL;
  const uint64_t tenant_id = get_effective_tenant_id();
  int64_t refreshed_schema_version = OB_INVALID_VERSION;
  if (!check_sys_variable_) {
    // 为了避免获取租户系统变量的SQL触发update_query_sensitive_system_variable形成循环依赖，这里直接跳过
  } else if (OB_FAIL(schema_guard.get_schema_version(tenant_id, refreshed_schema_version))) {
    LOG_WARN("fail to get tenant schema version", K(ret), K(tenant_id));
  } else if (OB_CORE_SCHEMA_VERSION >= refreshed_schema_version) {
    // 建租户过程 or 建租户失败 or 本地schema未刷新出来的场景，大概率获取不到系统变量，此时跳过
  } else if (OB_FAIL(schema_guard.get_sys_variable_schema(tenant_id, sys_variable_schema))) {
    LOG_WARN("get tenant schema version failed", K(ret), K(tenant_id));
  } else if (OB_ISNULL(sys_variable_schema)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("sys variable schema should not be null", K(ret), K(tenant_id));
  } else if (FALSE_IT(schema_version = sys_variable_schema->get_schema_version())) {
    ret = OB_ERR_UNEXPECTED;
  } else if (schema_version > get_global_vars_version()
             && schema_version > OB_CORE_SCHEMA_VERSION) { //系统变量schema_version有效才更新
    const ObTenantSchema *tenant_info = NULL;
    bool need_update_version = false;
    const ObSysVariableSchema *sys_variable_schema = NULL;
    if (OB_FAIL(schema_guard.get_tenant_info(get_effective_tenant_id(), tenant_info))) {
      LOG_WARN("get tenant info from schema guard failed", K(ret));
    } else if (OB_FAIL(schema_guard.get_sys_variable_schema(get_effective_tenant_id(), sys_variable_schema))) {
      if (OB_TENANT_NOT_EXIST == ret) {
        // 新建租户过程可能获取不到sys_variable_schema，此时先暂时忽略
        LOG_INFO("tenant maybe creating, just skip", K(ret), K(ret));
        ret = OB_SUCCESS;
      } else {
        LOG_WARN("get sys variable schema failed", K(ret));
      }
    } else if (OB_ISNULL(sys_variable_schema)) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("sys variable schema is null", K(ret));
    } else {
      for (int64_t i = 0; OB_SUCC(ret) && i < sys_variable_schema->get_sysvar_count(); ++i) {
        sysvar = sys_variable_schema->get_sysvar_schema(i);
        if (sysvar != NULL && sysvar->is_query_sensitive()) {
          if (OB_FAIL(update_sys_variable(sysvar->get_name(), sysvar->get_value()))) {
            if (OB_ERR_SYS_VARIABLE_UNKNOWN == ret) {
              //刷出来的variable可能是来自于一个更高的版本，本地没有，忽略掉
              ret = OB_SUCCESS;
            } else {
              LOG_WARN("update system variable failed", K(ret), K(*sysvar));
            }
          } else {
            need_update_version = true;
          }
        }
      }
      if (OB_SUCC(ret) && need_update_version) {
        set_global_vars_version(schema_version);
      }
    }
  }
  return ret;
}

int ObBasicSessionInfo::load_default_sys_variable(const bool print_info_log, const bool is_sys_tenant)
{
  int ret = OB_SUCCESS;
  if (OB_FAIL(sys_var_fac_.create_all_sys_vars())) {
    LOG_WARN("fail create all sys variables", K(ret));
  } else if (OB_FAIL(init_system_variables(print_info_log, is_sys_tenant))) {
    LOG_WARN("Init system variables failed !", K(ret));
  } else {
    variables_last_modify_time_ = ObTimeUtility::current_time();
  }
  return ret;
}

//这个函数使用时机: 在升级期间从低版本session发至高版本后, 可能会补充某个系统变量值.
//用于session反序列化
int ObBasicSessionInfo::load_default_sys_variable(ObIAllocator &calc_buf, int64_t var_idx)
{
  int ret = OB_SUCCESS;
  ObString name;
  ObObj type;
  ObObj value;
  ObObj min_val;
  ObObj max_val;
  ObObjType var_type = ObNullType;
  int64_t var_flag = ObSysVarFlag::NONE;
  if (var_idx < 0 || var_idx >= ObSysVarFactory::ALL_SYS_VARS_COUNT) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("the value of var_idx is unexpected", K(ret));
  } else {
    name.assign_ptr(const_cast<char*>(ObSysVariables::get_name(var_idx).ptr()),
                    static_cast<ObString::obstr_size_t>(strlen(ObSysVariables::get_name(var_idx).ptr())));
    var_type = ObSysVariables::get_type(var_idx);
    var_flag = ObSysVariables::get_flags(var_idx);
    value.set_varchar(ObSysVariables::get_value(var_idx));
    value.set_collation_type(ObCharset::get_system_collation());
    min_val.set_varchar(ObSysVariables::get_min(var_idx));
    min_val.set_collation_type(ObCharset::get_system_collation());
    max_val.set_varchar(ObSysVariables::get_max(var_idx));
    max_val.set_collation_type(ObCharset::get_system_collation());
    type.set_type(var_type);
    if (OB_FAIL(load_sys_variable(calc_buf, name, type, value, min_val, max_val, var_flag, false))) {
      LOG_WARN("fail to load default system variable", K(name), K(ret));
    }
  }
  return ret;
}

// Time to use this function:
//        pre calculation for empty session
int ObBasicSessionInfo::load_default_configs_in_pc()
{
  int ret = OB_SUCCESS;
  inf_pc_configs_.pushdown_storage_level_ = ObConfigInfoInPC::DEFAULT_PUSHDOWN_STORAGE_LEVEL;
  return ret;
}

int ObBasicSessionInfo::process_variable_for_tenant(const ObString &var, ObObj &val)
{
  int ret = OB_SUCCESS;
  if(0 == var.compare(OB_SV_LOWER_CASE_TABLE_NAMES)) {
    val.set_varchar("2");
    val.set_collation_type(ObCharset::get_system_collation());
  }
  return ret;
}

int ObBasicSessionInfo::create_sys_var(ObSysVarClassType sys_var_id,
                                       int64_t store_idx, ObBasicSysVar *&sys_var)
{
  int ret = OB_SUCCESS;
  OV (0 <= store_idx && store_idx < ObSysVarFactory::ALL_SYS_VARS_COUNT,
      OB_ERR_UNEXPECTED, sys_var_id, store_idx);
  if (OB_NOT_NULL(sys_vars_[store_idx])) {
    OV (sys_vars_[store_idx]->get_type() == sys_var_id,
        OB_ERR_UNEXPECTED, sys_var_id, store_idx, sys_vars_[store_idx]->get_type());
    OX (sys_var = sys_vars_[store_idx]);
  } else {
    OZ (sys_var_fac_.create_sys_var(sys_var_id, sys_var), sys_var_id);
    OV (OB_NOT_NULL(sys_var), OB_ERR_UNEXPECTED, sys_var_id, store_idx);
    OX (sys_vars_[store_idx] = sys_var);
  }
  return ret;
}

int ObBasicSessionInfo::inner_get_sys_var(const ObString &sys_var_name,
                                          int64_t &store_idx,
                                          ObBasicSysVar *&sys_var) const
{
  int ret = OB_SUCCESS;
  ObSysVarClassType sys_var_id = SYS_VAR_INVALID;
  if (OB_UNLIKELY(SYS_VAR_INVALID == (
              sys_var_id = ObSysVarFactory::find_sys_var_id_by_name(sys_var_name)))) {
    ret = OB_ERR_SYS_VARIABLE_UNKNOWN;
    LOG_WARN("fail to find sys var id by name", K(ret), K(sys_var_name), K(lbt()));
  } else if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(sys_var_id, store_idx))) {
    LOG_WARN("fail to calc sys var store idx", K(ret), K(sys_var_id), K(sys_var_name), K(lbt()));
  } else if (OB_UNLIKELY(store_idx < 0) ||
             OB_UNLIKELY(store_idx >= ObSysVarFactory::ALL_SYS_VARS_COUNT)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("got store_idx is invalid", K(ret), K(store_idx));
  } else if (OB_ISNULL(sys_vars_[store_idx])) {
    ret = OB_ENTRY_NOT_EXIST;
    LOG_WARN("sys var is NULL", K(ret), K(store_idx), K(sys_var_name));
  } else {
    sys_var = sys_vars_[store_idx];
  }
  return ret;
}

int ObBasicSessionInfo::inner_get_sys_var(const ObSysVarClassType sys_var_id,
                                          int64_t &store_idx,
                                          ObBasicSysVar *&sys_var) const
{
  int ret = OB_SUCCESS;
  if (OB_UNLIKELY(SYS_VAR_INVALID == sys_var_id)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_ERROR("invalid sys var id", K(ret), K(sys_var_id), K(lbt()));
  } else if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(sys_var_id, store_idx))) {
    LOG_WARN("fail to calc sys var store idx", K(ret), K(sys_var_id), K(lbt()));
  } else if (OB_UNLIKELY(store_idx < 0) ||
             OB_UNLIKELY(store_idx >= ObSysVarFactory::ALL_SYS_VARS_COUNT)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("got store_idx is invalid", K(ret), K(store_idx));
  } else if (OB_ISNULL(sys_vars_[store_idx])) {
    ret = OB_ENTRY_NOT_EXIST;
    LOG_WARN("sys var is NULL", K(ret), K(store_idx));
  } else {
    sys_var = sys_vars_[store_idx];
  }
  return ret;
}

int ObBasicSessionInfo::change_value_for_special_sys_var(const ObString &sys_var_name,
                                                         const ObObj &ori_val,
                                                         ObObj &new_val)
{
  int ret = OB_SUCCESS;
  ObSysVarClassType sys_var_id = ObSysVarFactory::find_sys_var_id_by_name(sys_var_name);
  if (OB_UNLIKELY(SYS_VAR_INVALID == sys_var_id)) {
    LOG_WARN("fail to find sys var id by name", K(ret), K(sys_var_name));
  } else if (OB_FAIL(ObBasicSessionInfo::change_value_for_special_sys_var(
              sys_var_id, ori_val, new_val))) {
    LOG_WARN("fail to change value for special sys var", K(ret),
             K(sys_var_name), K(sys_var_id), K(ori_val));
  }
  return ret;
}

int ObBasicSessionInfo::change_value_for_special_sys_var(const ObSysVarClassType sys_var_id,
                                                         const ObObj &ori_val,
                                                         ObObj &new_val)
{
  int ret = OB_SUCCESS;
  int64_t sys_var_store_idx = -1;
  if (SYS_VAR_VERSION_COMMENT == sys_var_id
      || (SYS_VAR_VERSION == sys_var_id && 0 == ori_val.val_len_) //version not changed by user
      || SYS_VAR_SYSTEM_TIME_ZONE == sys_var_id) {
    if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(sys_var_id, sys_var_store_idx))) {
      LOG_WARN("fail to calc sys var store idx", K(ret), K(sys_var_id));
    } else if (SYS_VAR_VERSION == sys_var_id && 0 == ori_val.val_len_) {
      new_val.set_varchar(ObSpecialSysVarValues::version_);
      new_val.set_collation_type(CS_TYPE_UTF8MB4_GENERAL_CI);
      new_val.set_collation_level(CS_LEVEL_SYSCONST);
    } else {
      new_val = ObSysVariables::get_default_value(sys_var_store_idx);
    }
  } else {
    new_val = ori_val;
  }
  return ret;
}


// 此函数中会调用ObBasicSessionInfo::change_value_for_special_sys_var改变一些值，
// 仅用于ObMPBase::load_system_variables中，
// 其他地方慎用
int ObBasicSessionInfo::load_sys_variable(ObIAllocator &calc_buf,
                                          const ObString &name,
                                          const ObObj &type,
                                          const ObObj &value,
                                          const ObObj &min_val,
                                          const ObObj &max_val,
                                          const int64_t flags,
                                          bool is_from_sys_table)
{
  int ret = OB_SUCCESS;
  ObObj casted_cell;
  ObBasicSysVar *sys_var = NULL;
  ObSysVarClassType var_id = SYS_VAR_INVALID;
  ObObj real_val;
  ObObj val_ptr;
  ObObj min_ptr;
  ObObj max_ptr;
  ObObj val_type;
  ObObj tmp_type;
  int64_t store_idx = -1;
  if (SYS_VAR_INVALID == (var_id = ObSysVarFactory::find_sys_var_id_by_name(name, is_from_sys_table))) {
    if (is_from_sys_table) {
      ret = OB_SUCCESS;
    } else {
      ret = OB_ERR_SYS_VARIABLE_UNKNOWN;
      LOG_ERROR("failed to find system variable", K(ret), K(name));
    }
  } else if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(var_id, store_idx))) {
    LOG_WARN("fail to calc sys var store idx", K(ret), K(var_id));
  } else if (OB_FAIL(cast_sys_variable(calc_buf, false, var_id, type, value, flags, val_type, val_ptr))) {
    LOG_WARN("fail to cast system variable", K(var_id), K(type), K(value), K(flags),K(val_ptr), K(ret));
  } else if (OB_FAIL(cast_sys_variable(calc_buf, true, var_id, type, min_val, flags, tmp_type, min_ptr))) {
    LOG_WARN("fail to cast system variable", K(var_id), K(type), K(min_val), K(flags), K(min_val), K(min_ptr), K(ret));
  } else if (OB_FAIL(cast_sys_variable(calc_buf, true, var_id, type, max_val, flags, tmp_type, max_ptr))) {
    LOG_WARN("fail to cast system variable", K(var_id), K(type), K(max_val), K(flags), K(max_ptr), K(ret));
  } else if (OB_FAIL(create_sys_var(var_id, store_idx, sys_var))) {
    LOG_WARN("fail to create sys var", K(name), K(value), K(ret));
  } else if (OB_ISNULL(sys_var)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("sys var is NULL", K(name), K(value), K(ret));
  } else if (OB_FAIL(ObBasicSessionInfo::change_value_for_special_sys_var(
              var_id, val_ptr, real_val))) {
    LOG_WARN("fail to change value for special sys var", K(ret), K(var_id), K(val_ptr));
  } else if (OB_FAIL(sys_var->init(real_val, min_ptr, max_ptr, val_type.get_type(), flags))) {
    LOG_WARN("fail to init sys var", K(ret), K(sys_var->get_type()),
             K(real_val), K(name), K(value));
  } else if (OB_FAIL(process_session_variable(var_id, real_val,
                                              false /*check_timezone_valid*/,
                                              false /*is_update_sys_var*/))) {
    LOG_WARN("process system variable error",  K(name), K(type), K(real_val), K(value), K(ret));
  } else {
    variables_last_modify_time_ = ObTimeUtility::current_time();
  }
  return ret;
}

// 此函数中会调用ObBasicSessionInfo::change_value_for_special_sys_var改变一些值，
// 仅用于ObMPBase::load_system_variables中，
// 其他地方慎用
int ObBasicSessionInfo::load_sys_variable(ObIAllocator &calc_buf,
                                          const ObString &name,
                                          const int64_t dtype,
                                          const ObString &value_str,
                                          const ObString &min_val_str,
                                          const ObString &max_val_str,
                                          const int64_t flags,
                                          bool is_from_sys_table /*= false*/)
{
  int ret = OB_SUCCESS;
  ObObj value, min_val, max_val;
  ObObj otype;
  value.set_varchar(value_str);
  value.set_collation_type(ObCharset::get_system_collation());
  min_val.set_varchar(min_val_str);
  min_val.set_collation_type(ObCharset::get_system_collation());
  max_val.set_varchar(max_val_str);
  max_val.set_collation_type(ObCharset::get_system_collation());
  otype.set_type(static_cast<ObObjType>(dtype));
  if (OB_FAIL(load_sys_variable(calc_buf, name, otype, value, min_val, max_val,
                                flags, is_from_sys_table))) {
    LOG_WARN("fail to load system variable", K(name), K(otype), K(value),
             K(min_val), K(max_val), K(flags), K(is_from_sys_table), K(ret));
  }
  return ret;
}

int ObBasicSessionInfo::cast_sys_variable(ObIAllocator &calc_buf,
                                          bool is_range_value,
                                          const ObSysVarClassType sys_var_id,
                                          const ObObj &type,
                                          const ObObj &value,
                                          int64_t flags,
                                          ObObj &out_type,
                                          ObObj &out_value)
{
  UNUSED(sys_var_id);
  int ret = OB_SUCCESS;
  ObObj casted_cell;
  if (ObVarcharType != value.get_type()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid type", K(value), K(ret));
  } else {
    // 为max_val和min_val进行判断，variable的value值不会进入此判断
    if (is_range_value
        && value.get_varchar() == ObString::make_string(ObBasicSysVar::EMPTY_STRING)) {
      out_value.set_null();
    } else if (ObBasicSysVar::is_null_value(value.get_varchar(), flags)) {
      out_value.set_null();
    } else {
      ObDataTypeCastParams dtc_params = get_dtc_params();
      ObCastCtx cast_ctx(&calc_buf, &dtc_params, CM_NONE, ObCharset::get_system_collation());
      if (OB_FAIL(ObObjCaster::to_type(type.get_type(),
                                       ObCharset::get_system_collation(),
                                       cast_ctx,
                                       value,
                                       casted_cell))) {
        _LOG_WARN("failed to cast object, cell=%s from_type=%s to_type=%s ret=%d ",
                  to_cstring(value), ob_obj_type_str(value.get_type()),
                  ob_obj_type_str(type.get_type()), ret);
      } else if (OB_FAIL(base_sys_var_alloc_.write_obj(casted_cell, &out_value))) {
        LOG_WARN("fail to store variable value", K(casted_cell), K(value), K(ret));
      } else {
        if (ob_is_string_type(out_value.get_type())) {
          out_value.set_collation_level(CS_LEVEL_SYSCONST);
          if (CS_TYPE_INVALID == out_value.get_collation_type()) {
            out_value.set_collation_type(ObCharset::get_system_collation());
          }
        }
      }
    }
    if (OB_SUCC(ret)) {
      out_type.set_type(type.get_type());
    }
  }
  return ret;
}

bool sys_var_compare(const SysVarNameVal &left,const SysVarNameVal &right)
{
  return left.name_ < right.name_;
}

/*
 *获取影响physical plan的系统变量,以下系统变量会影响plan cache正确命中plan，需要在plan cache中进行处理
 *read_only:
    ObSql中在resolver之后，生成逻辑计划之前用来判断db和table是否为只读，其变化会影响plan cache正确命中。
 *ob_enable_transformation
    ObSql中在resolver之后，生成逻辑计划前判断是否进行改写，会影响生成plan的结构。
 *binlog_row_image
    在resolver中会使用,对生成的plan有影响。
 *collation_connection
    在resolver中使用，对plan有影响。
 * sql_auto_is_null
    在resolver中使用，对plan有影响。
 *div_precision_increment
    expr的类型推导中会使用，暂时未将该变量传进去，使用的是hard coding, bug:1043693;
 *ob_enable_aggregation_pushdown
    在优化器中使用，会影响生成的plan。
 *ob_enable_index_direct_select
    在resolver中使用，判断是否可以使用索引表，影响plan cache正确命中。
 *sql_mode
    在resolver中有使用，会影响生成的plan。
 *ob_route_policy
    影响副本的类型的选项，进而影响决定是local还是remote的计划。plan cache当一次执行成功的local 语句，这次默认仍旧按照local执行
    并不会去判断location，如果期间更改了ob_route_policy，则会导致无法从新选择副本。
 *ob_read_consistency
    会影响replica的选择，进行影响plan
 */
//内部连接与外部连接获取到的sys_val顺序不一致，内部连接与外部连接执行同一sql不能命中同一plan,
//暂不影响线上的plan cache命中率
int ObBasicSessionInfo::get_influence_plan_sys_var(ObSysVarInPC &sys_vars) const
{
  int ret = OB_SUCCESS;
  //get influence_plan_sys_var from sys_var_val_map
  int64_t index = 0;
  for (int64_t i = 0; OB_SUCC(ret) && i < get_influence_plan_var_count(); ++i) {
    index = influence_plan_var_indexs_.at(i);
    if (index >= ObSysVarFactory::ALL_SYS_VARS_COUNT) {
      ret = OB_ERR_UNEXPECTED;
      LOG_ERROR("influence plan system var indexs out of range", K(i), K(ret));
    } else if (NULL == sys_vars_[index]) {
      ret = OB_ERR_UNEXPECTED;
      LOG_ERROR("influence plan system var is NULL", K(i), K(ret));
    } else if (OB_FAIL(sys_vars.push_back(sys_vars_[index]->get_value()))) {
      LOG_WARN("influence plan system variables push failed", K(ret));
    }
  }
  return ret;
}

/*
 **内部session与用户session对应的影响plan的系统变量的顺序
 *
 *    inner_session                                           user_session
 *
 * 45,4194304,2,4,1,0,0,32,1,0,1,1,0,10485760,1            2,45,4,1,10485760,1,0,1,0,1,32,1,0,0,4194304
 *
 *1  collation_connection,                                   binlog_row_image,
 *2  sql_mode,                                               collation_connection,
 *3  binlog_row_image,                                       div_precision_increment,
 *4  div_precision_increment,                                explicit_defaults_for_timestamp,
 *5  explicit_defaults_for_timestamp,                        ob_bnl_join_cache_size,
 *6  read_only,                                              ob_enable_aggregation_pushdown,
 *7  ql_auto_is_null,                                        ob_enable_blk_nestedloop_join,
 *8  ,                                                       ob_enable_hash_group_by,
 *9  ob_enable_transformation,                               ob_enable_index_direct_select,
 *10 ob_enable_index_direct_select,                          b_enable_transformation,
 *11 ob_enable_aggregation_pushdown,                         ,
 *12 ob_enable_hash_group_by,                                ,
 *13 ob_enable_blk_nestedloop_join,                          read_only,
 *14 ob_bnl_join_cache_size,                                 sql_auto_is_null,
 *15 ,                                                       sql_mode,
*/
int ObBasicSessionInfo::gen_sys_var_in_pc_str()
{
  int ret = OB_SUCCESS;
  const int64_t MAX_SYS_VARS_STR_SIZE = 1024;
  ObSysVarInPC sys_vars;
  char *buf = NULL;
  int64_t pos = 0;
  if (is_first_gen_) {
    //如果是第一次则需要分配内存
    if (NULL == (buf = (char *)name_pool_.alloc(MAX_SYS_VARS_STR_SIZE))) {
      ret = OB_ALLOCATE_MEMORY_FAILED;
      LOG_WARN("fail to allocator memory", K(ret), K(MAX_SYS_VARS_STR_SIZE));
    } else {
      set_sys_vars_encode_max_size(MAX_SYS_VARS_STR_SIZE);
      is_first_gen_ = false;
    }
  } else {
    buf = sys_var_in_pc_str_.ptr();
    MEMSET(buf, 0, sys_var_in_pc_str_.length());
    sys_var_in_pc_str_.reset();
  }
  int64_t sys_var_encode_max_size = get_sys_vars_encode_max_size();
  if (OB_FAIL(ret)) {
  } else if (OB_FAIL(get_influence_plan_sys_var(sys_vars))) {
    LOG_WARN("fail to get influence plan system variables", K(ret));
  } else if (OB_FAIL(sys_vars.serialize_sys_vars(buf, sys_var_encode_max_size, pos))) {
    if (OB_BUF_NOT_ENOUGH == ret || OB_SIZE_OVERFLOW ==ret) {
      ret = OB_SUCCESS;
      // expand MAX_SYS_VARS_STR_SIZE 3 times.
      for (int64_t i = 0; OB_SUCC(ret) && i < 3; ++i) {
        sys_var_encode_max_size = 2 * sys_var_encode_max_size;
        if (NULL == (buf = (char *)name_pool_.alloc(sys_var_encode_max_size))) {
          ret = OB_ALLOCATE_MEMORY_FAILED;
          LOG_WARN("fail to allocator memory", K(ret), K(sys_var_encode_max_size));
        } else if (OB_FAIL(sys_vars.serialize_sys_vars(buf, sys_var_encode_max_size, pos))) {
          if (i != 2 && (OB_BUF_NOT_ENOUGH == ret || OB_SIZE_OVERFLOW ==ret)) {
            ret = OB_SUCCESS;
          } else {
            LOG_WARN("fail to serialize system vars", K(ret));
          }
        } else {
          break;
        }
      }
    } else {
      LOG_WARN("fail to serialize system vars", K(ret));
    }
    if (OB_SUCC(ret)) {
      set_sys_vars_encode_max_size(sys_var_encode_max_size);
      (void)sys_var_in_pc_str_.assign(buf, int32_t(pos));
    }
  } else {
    (void)sys_var_in_pc_str_.assign(buf, int32_t(pos));
  }

  return ret;
}

int ObBasicSessionInfo::update_sys_variable_by_name(const ObString &var, const ObObj &val)
{
  int ret = OB_SUCCESS;
  ObSysVarClassType var_id = SYS_VAR_INVALID;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(val), K(ret));
  } else if (SYS_VAR_INVALID == (var_id = ObSysVarFactory::find_sys_var_id_by_name(var))) {
    ret = OB_ERR_SYS_VARIABLE_UNKNOWN;
    LOG_WARN("unknown variable", K(var), K(val), K(ret));
  } else if (OB_FAIL(update_sys_variable(var_id, val))) {
    LOG_WARN("failed to update sys variable", K(var), K(val), K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::update_sys_variable_by_name(const common::ObString &var, int64_t val)
{
  ObObj obj;
  obj.set_int(val);
  return update_sys_variable_by_name(var, obj);
}

int ObBasicSessionInfo::update_sys_variable(const ObSysVarClassType sys_var_id, const ObString &val)
{
  ObObj obj;
  obj.set_varchar(val);
  obj.set_collation_type(ObCharset::get_system_collation());
  return update_sys_variable(sys_var_id, obj);
}

int ObBasicSessionInfo::update_sys_variable(const ObSysVarClassType sys_var_id, const int64_t val)
{
  ObObj obj;
  obj.set_int(val);
  return update_sys_variable(sys_var_id, obj);
}

int ObBasicSessionInfo::update_sys_variable(const ObString &var, const ObString &val)
{
  int ret = OB_SUCCESS;
  ObSysVarClassType sys_var_id = SYS_VAR_INVALID;
  ObBasicSysVar *sys_var = NULL;
  if (OB_UNLIKELY(SYS_VAR_INVALID == (sys_var_id = ObSysVarFactory::find_sys_var_id_by_name(var)))) {
    ret = OB_ERR_SYS_VARIABLE_UNKNOWN;
    LOG_WARN("unknown variable", K(var), K(val), K(ret));
  } else if (OB_FAIL(inner_get_sys_var(sys_var_id, sys_var))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(var), K(val));
  } else if (OB_ISNULL(sys_var)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(var));
  } else {
    // trim quotation marks
    ObString tmp_val;
    if (val.length() > 1 && (('\'' == val[0]
        && '\'' == val[val.length() - 1])
        || ('\"' == val[0]
        && '\"' == val[val.length() - 1]))) {
      tmp_val.assign_ptr(val.ptr() + 1, val.length() - 2);
    } else {
      tmp_val.assign_ptr(val.ptr(), val.length());
    }
    // 将varchar类型转换为实际类型
    ObObj in_obj;
    in_obj.set_varchar(tmp_val);
    in_obj.set_collation_type(ObCharset::get_system_collation());
    const ObObj *out_obj = NULL;
    ObObj buf_obj;
    ObArenaAllocator calc_buf(ObModIds::OB_SQL_SESSION);
    ObDataTypeCastParams dtc_params = get_dtc_params();
    ObCastCtx cast_ctx(&calc_buf, &dtc_params, CM_NONE, ObCharset::get_system_collation());
    if (OB_FAIL(ObObjCaster::to_type(sys_var->get_data_type(), cast_ctx, in_obj, buf_obj, out_obj))) {
      LOG_WARN("failed to cast obj", "expected type", sys_var->get_meta_type(),
               K(ret), K(var), K(in_obj));
    } else if (OB_ISNULL(out_obj)) {
      ret = OB_ERR_UNEXPECTED;
      LOG_ERROR("casted success, but out_obj is NULL", K(in_obj), K(ret));
    } else if (OB_FAIL(update_sys_variable(sys_var_id, *out_obj))) {
      LOG_WARN("fail to update sys variable", K(ret), K(var), K(*out_obj));
    }
  }
  return ret;
}

int ObBasicSessionInfo::update_sys_variable(const ObSysVarClassType sys_var_id, const ObObj &val)
{
  int ret = OB_SUCCESS;
  ObObj obj;
  ObBasicSysVar *sys_var = NULL;
  int64_t sys_var_idx = 0;
  // 首先track变量的修改, 这样如果变量修改失败, 也不会造成客户端与服务端不一致的情况
  if (SYS_VAR_INVALID == sys_var_id) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid sys_var_id", K(sys_var_id), K(ret));
  } else if (OB_FAIL(inner_get_sys_var(sys_var_id, sys_var_idx, sys_var))) {
    LOG_WARN("failed to inner get sys var", K(ret), K(sys_var_id), K(val));
  } else if (OB_ISNULL(sys_var)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("failed to inner get sys var, sys var is null", K(ret), K(sys_var_id), K(val));
  } else if (is_track_session_info()) {
    if (OB_FAIL(track_sys_var(sys_var_id, sys_var->get_value()))) {
      LOG_WARN("failed to track sys var", K(ret), K(sys_var_id), K(val));
    } else {
      variables_last_modify_time_ = ObTimeUtility::current_time();
      LOG_DEBUG("succ to track system variable",
                K(ret), K(sys_var_id), K(val), K(sys_var->get_value()));
    }
  }
  // 更新变量
  if (OB_SUCC(ret)) {
    if (OB_FAIL(process_session_variable(sys_var_id, val, false /*check_timezone_valid*/,
                                        true /*is_update_sys_var*/))) {
      LOG_WARN("process system variable error",  K(sys_var_id), K(val), K(ret));
    } else if (OB_FAIL(sys_var_inc_info_.add_sys_var_id(sys_var_id))) {
      LOG_WARN("add sys var id error",  K(sys_var_id), K(ret));
    } else {
      // 如果设置的time_zone是一个offset而不是时区，那么对其做formalize，固定格式为 +/-HH:MM
      if (OB_UNLIKELY(SYS_VAR_TIME_ZONE == sys_var_id && ! tz_info_wrap_.is_position_class())) {
        const int64_t buf_len = 16;
        char tmp_buf[buf_len] = {0};
        int64_t pos = 0;
        ObObj tmp_obj = val;
        if (OB_ISNULL(tz_info_wrap_.get_time_zone_info())) {
          ret = OB_ERR_UNEXPECTED;
          LOG_WARN("time zone info is null", K(ret));
        } else if (OB_FAIL(tz_info_wrap_.get_time_zone_info()->timezone_to_str(
                                              tmp_buf, buf_len, pos))) {
          LOG_WARN("timezone to str failed", K(ret));
        } else {
          tmp_obj.set_common_value(ObString(pos, tmp_buf));
          if (OB_FAIL(deep_copy_sys_variable(*sys_var, sys_var_id, tmp_obj))) {
            LOG_WARN("deep copy sys var failed", K(ret));
          }
        }
      } else {
        if (ob_is_string_type(val.get_type())) {
          if (OB_FAIL(deep_copy_sys_variable(*sys_var, sys_var_id, val))) {
            LOG_WARN("fail to update system variable", K(sys_var_id), K(val), K(ret));
          }
        } else if (ob_is_number_tc(val.get_type())) {
          if (OB_FAIL(deep_copy_sys_variable(*sys_var, sys_var_id, val))) {
            LOG_WARN("fail to update system variable", K(sys_var_id), K(val), K(ret));
          }
        } else {
          // int, bool, enum, uint do not need to do deep copy
          sys_var->set_value(val);
        }
      }
    }
  }
  // 处理PLAN_CHACHE相关的变量
  if (OB_SUCC(ret)
			&& !is_deserialized_
      && sys_var->is_influence_plan()
      && OB_FAIL(gen_sys_var_in_pc_str())) {
    LOG_ERROR("fail to gen sys var in pc str", K(ret));
  }
  return ret;
}

int ObBasicSessionInfo::gen_configs_in_pc_str()
{
  int ret = OB_SUCCESS;
  const int64_t MAX_CONFIG_STR_SIZE = 512;
  char *buf = NULL;
  int64_t pos = 0;
  if (!GCONF.is_valid()) {
    // do nothing
  } else {
    int64_t cluster_config_version = GCONF.get_current_version();
    int64_t tenant_config_version = (::oceanbase::omt::ObTenantConfigMgr::get_instance()).get_tenant_config_version(tenant_id_);

    if (!config_in_pc_str_.empty() &&
          !inf_pc_configs_.is_out_of_date(cluster_config_version, tenant_config_version)) {
      // unupdated configs do nothing
    } else {
      // update out-dated cached configs
      // first time to generate configuaration strings, init allocator
      if (is_first_gen_config_) {
        inf_pc_configs_.init(tenant_id_);
        if (NULL == (buf = (char *)name_pool_.alloc(MAX_CONFIG_STR_SIZE))) {
          ret = OB_ALLOCATE_MEMORY_FAILED;
          LOG_WARN("fail to allocate memory", K(ret), K(MAX_CONFIG_STR_SIZE));
        }
        is_first_gen_config_ = false;
      } else {
        // reuse memory
        buf = config_in_pc_str_.ptr();
        MEMSET(buf, 0, config_in_pc_str_.length());
        config_in_pc_str_.reset();
      }

      // update configs
      if (OB_FAIL(ret)) {
      } else if (OB_FAIL(inf_pc_configs_.load_influence_plan_config())) {
        LOG_WARN("failed to load configurations that will influence executions plan.", K(ret));
      } else if (OB_FAIL(inf_pc_configs_.serialize_configs(buf, MAX_CONFIG_STR_SIZE, pos))) {
        LOG_WARN("failed to serialize configs", K(ret));
      } else {
        (void)config_in_pc_str_.assign(buf, int32_t(pos));
        inf_pc_configs_.update_version(cluster_config_version, tenant_config_version);
      }
    }
  }
  return ret;
}

int ObBasicSessionInfo::deep_copy_trace_id_var(const ObObj &src_val,
                                               ObObj *dest_val_ptr)
{
  int ret = OB_SUCCESS;
  if (OB_ISNULL(dest_val_ptr)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("dest val ptr is NULL", K(ret));
  } else {
    *dest_val_ptr = src_val;
    ObString new_str;
    ObString src_str;
    const int64_t STR_BUFF_LEN = sizeof(trace_id_buff_);
    int64_t src_str_len = 0;
    if (OB_FAIL(src_val.get_varchar(src_str))) {
      LOG_WARN("fail to get varchar", K(src_val), K(ret));
    } else if (OB_UNLIKELY((src_str_len = src_str.length()) == 0)) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("invalid string", K(src_str), K(ret));
    } else if (STR_BUFF_LEN <= src_str_len) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("invalid src str len", K(src_str_len), K(ret));
    } else {
      MEMCPY(trace_id_buff_, src_str.ptr(), src_str_len);
      trace_id_buff_[src_str_len] = '\0';
      new_str.assign_ptr(trace_id_buff_, static_cast<ObString::obstr_size_t>(src_str_len));
      dest_val_ptr->set_varchar(new_str);
    }
  }
  return ret;
}

//该接口中使用的name_pool_是一个只申请不释放的内存，暂时仅对会频繁更新的trace_id做优化
int ObBasicSessionInfo::deep_copy_sys_variable(ObBasicSysVar &sys_var,
                                               const ObSysVarClassType sys_var_id,
                                               const ObObj &src_val)
{
  int ret = OB_SUCCESS;
  ObObj dest_val;
  if (OB_UNLIKELY(sys_var_id == SYS_VAR_OB_STATEMENT_TRACE_ID)) {
    if (OB_FAIL(deep_copy_trace_id_var(src_val, &dest_val))) {
      LOG_WARN("fail to deep copy trace id", K(ret));
    } else {
      sys_var.set_value(dest_val);
    }
  } else {
    if (OB_FAIL(inc_sys_var_alloc_.write_obj(src_val, &dest_val))) {
      LOG_WARN("fail to write obj", K(src_val), K(ret));
    } else {
      if (ob_is_string_type(src_val.get_type())) {
        dest_val.set_collation_level(CS_LEVEL_SYSCONST);
        if (CS_TYPE_INVALID == src_val.get_collation_type()) {
          dest_val.set_collation_type(ObCharset::get_default_collation(ObCharset::get_default_charset()));
        }
      }
      sys_var.set_value(dest_val);
    }

    // defragment.
    // https://work.aone.alibaba-inc.com/issue/39958139
    if (OB_SUCC(ret)) {
      if (inc_sys_var_alloc_.used() > next_frag_mem_point_) {
        // Note: this defrag impl. algrothim is not efficient.
        // howerver, considering it is not the common path, we don't expect to be here very often.
        // for an efficient impl. please refer https://yuque.antfin-inc.com/xiaochu.yh/doc/oa9az6
        common::ObStringBuf tmp_buf(ObModIds::OB_SQL_SESSION, OB_MALLOC_NORMAL_BLOCK_SIZE);
        if (OB_FAIL(defragment_sys_variable_to(tmp_buf))) {
          LOG_WARN("fail to defrag sys variable memory to temp alloc", K(ret));
        } else {
          LOG_INFO("Too much memory used for system variable values. do defragment",
                    "before", inc_sys_var_alloc_.used(), "after", tmp_buf.used());
          inc_sys_var_alloc_.reset();
          if (OB_FAIL(defragment_sys_variable_to(inc_sys_var_alloc_))) {
            LOG_WARN("fail to defrag sys variable memory to base sys var alloc", K(ret));
          } else {
            next_frag_mem_point_ = std::max(2 * inc_sys_var_alloc_.used(), OB_MALLOC_NORMAL_BLOCK_SIZE);
          }
        }
      }
    }
  }
  return ret;
}

int ObBasicSessionInfo::defragment_sys_variable_to(common::ObStringBuf &allocator)
{
  int ret = OB_SUCCESS;
  const SysVarIds &all_sys_var_ids = sys_var_inc_info_.get_all_sys_var_ids();
  for (int i = 0; i < all_sys_var_ids.count(); i++) {
    int64_t store_idx = -1;
    ObSysVarClassType sys_var_id = all_sys_var_ids.at(i);
    OZ (ObSysVarFactory::calc_sys_var_store_idx(sys_var_id, store_idx));
    OV (0 <= store_idx && store_idx < ObSysVarFactory::ALL_SYS_VARS_COUNT);
    OV (OB_NOT_NULL(sys_vars_[store_idx]));
    if (OB_SUCC(ret)) {
      const ObObj &src_val = sys_vars_[store_idx]->get_value();
      if (ob_is_string_type(src_val.get_type()) || ob_is_number_tc(src_val.get_type())) {
        ObObj dest_val;
        if (OB_FAIL(allocator.write_obj(src_val, &dest_val))) {
          LOG_WARN("fail to write obj", K(src_val), K(ret));
        } else {
          sys_vars_[store_idx]->set_value(dest_val);
        }
      }
    }
  }
  return ret;
}

int ObBasicSessionInfo::update_session_sys_variable(ObExecContext &ctx,
                                                    const ObString &var,
                                                    const ObObj &val)
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *sys_var = NULL;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(ret), K(var));
  } else if (OB_FAIL(inner_get_sys_var(var, sys_var))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(var), K(val));
  } else if (OB_ISNULL(sys_var)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(var), K(val));
  } else {
    ObMySQLProxy sql_proxy;
    ObSetVar set_var(var, ObSetVar::SET_SCOPE_SESSION, false, OB_INVALID_ID, ctx.get_allocator(), sql_proxy);
    if (OB_FAIL(sys_var->session_update(ctx, set_var, val))) {
      LOG_WARN("session update system variable failed", K(ret), K(set_var));
    } else if (OB_FAIL(sys_var->update(ctx, set_var, val))) {
      LOG_WARN("fail to update sys var", K(ret), K(var), K(val));
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_sys_variable_by_name(const ObString &var, ObBasicSysVar *&val) const
{
  int ret = OB_SUCCESS;
  if (OB_UNLIKELY(var.empty())) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
  } else if (OB_FAIL(inner_get_sys_var(var, val))) {
    LOG_WARN("fail to inner get sys var", K(var), K(ret));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(var));
  } else {}
  return ret;
}

int ObBasicSessionInfo::get_sys_variable_by_name(const ObString &var, ObObj &val) const
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *sys_var = NULL;
  if (OB_UNLIKELY(var.empty())) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
  } else if (OB_FAIL(inner_get_sys_var(var, sys_var))) {
    LOG_WARN("fail to get sys var", K(ret), K(var));
  } else if (OB_ISNULL(sys_var)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to get sys var, but sys var is NULL", K(ret), K(var));
  } else {
    val = sys_var->get_value();
  }
  return ret;
}

int ObBasicSessionInfo::get_sys_variable_by_name(const common::ObString &var, int64_t &val) const
{
  int ret = OB_SUCCESS;
  ObObj obj;
  if (OB_FAIL(get_sys_variable_by_name(var, obj))) {
  } else if (OB_FAIL(obj.get_int(val))) {
    LOG_WARN("wrong obj type for system variable", K(var), K(obj), K(ret), K(obj.get_meta().is_int()), K(obj.get_meta().get_type()));
  } else {}
  return ret;
}

int ObBasicSessionInfo::get_sys_variable(const ObSysVarClassType sys_var_id,
                                         common::ObObj &val) const
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *var = NULL;
  if (OB_UNLIKELY(SYS_VAR_INVALID == sys_var_id)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid sys_var_id", K(ret), K(sys_var_id));
  } else if (OB_FAIL(inner_get_sys_var(sys_var_id, var))) {
    LOG_WARN("fail to get sys var", K(ret), K(var));
  } else if (OB_ISNULL(var)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to get sys var, but sys var is NULL", K(ret), K(var));
  } else {
    val = var->get_value();
  }
  return ret;
}

int ObBasicSessionInfo::get_sys_variable(const ObSysVarClassType sys_var_id,
                                         common::ObString &val) const
{
  int ret = OB_SUCCESS;
  ObObj obj;
  if (SYS_VAR_INVALID == sys_var_id) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid sys_var_id", K(sys_var_id), K(ret));
  } else if (OB_FAIL(get_sys_variable(sys_var_id, obj))) {
    LOG_WARN("failed to get system variable", K(sys_var_id), K(ret));
  } else if (OB_FAIL(obj.get_varchar(val))) { //这里不用考虑sql_mode兼容转换，因为sql_mode取值不通过这里，而是通过sql_mode_manager_
    LOG_WARN("wrong obj type for system variable", K(sys_var_id), K(obj), K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::get_sys_variable(const ObSysVarClassType sys_var_id, int64_t &val) const
{
  int ret = OB_SUCCESS;
  ObObj obj;
  if (OB_FAIL(get_sys_variable(sys_var_id, obj))) {
    LOG_WARN("failed to get system variable", K(sys_var_id), K(obj), K(ret));
  } else if (OB_FAIL(obj.get_int(val))) {
    LOG_WARN("wrong obj type for system variable", K(sys_var_id), K(obj), K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::get_sys_variable(const ObSysVarClassType sys_var_id, uint64_t &val) const
{
  int ret = OB_SUCCESS;
  ObObj obj;
  if (OB_FAIL(get_sys_variable(sys_var_id, obj))) {
    LOG_WARN("failed to get system variable", K(sys_var_id), K(obj), K(ret));
  } else if (OB_FAIL(obj.get_uint64(val))) {
    LOG_WARN("wrong obj type for system variable", K(ret), K(sys_var_id), K(obj));
  } else {}
  return ret;
}

int ObBasicSessionInfo::sys_variable_exists(const ObString &var, bool &is_exists) const
{
  int ret = OB_SUCCESS;
  is_exists = false;
  ObSysVarClassType sys_var_id = SYS_VAR_INVALID;
  int64_t store_idx = -1;
  if (SYS_VAR_INVALID == (sys_var_id = ObSysVarFactory::find_sys_var_id_by_name(var))) {
    LOG_DEBUG("sys var is not exist", K(var), K(ret));
  } else if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(sys_var_id, store_idx))) {
    LOG_WARN("fail to calc sys var store idx", K(sys_var_id), K(var), K(ret));
  } else if (store_idx < 0 || store_idx >= ObSysVarFactory::ALL_SYS_VARS_COUNT) {
    ret = OB_ERR_UNEXPECTED;
    LOG_ERROR("got store_idx is invalid", K(store_idx), K(ret));
  } else {
    is_exists = (NULL != sys_vars_[store_idx]);
  }
  return ret;
}

// for query and DML
int ObBasicSessionInfo::set_cur_phy_plan(ObPhysicalPlan *cur_phy_plan)
{
  int ret = OB_SUCCESS;
  if (OB_ISNULL(cur_phy_plan)) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("current physical plan is NULL", K(lbt()), K(ret));
  } else {
    cur_phy_plan_ = cur_phy_plan;
    plan_id_ = cur_phy_plan->get_plan_id();
    int64_t len = cur_phy_plan->stat_.sql_id_.length();
    MEMCPY(sql_id_, cur_phy_plan->stat_.sql_id_.ptr(), len);
    sql_id_[len] = '\0';
  }
  return ret;
}

// for cmd only
void ObBasicSessionInfo::set_cur_sql_id(char *sql_id)
{
  if (nullptr == sql_id) {
    sql_id_[0] = '\0';
  } else {
    MEMCPY(sql_id_, sql_id, common::OB_MAX_SQL_ID_LENGTH + 1);
  }
}

void ObBasicSessionInfo::get_cur_sql_id(char *sql_id_buf, int64_t sql_id_buf_size) const
{
  if (common::OB_MAX_SQL_ID_LENGTH + 1 <= sql_id_buf_size) {
    MEMCPY(sql_id_buf, sql_id_, common::OB_MAX_SQL_ID_LENGTH + 1);
  } else {
    sql_id_buf[0] = '\0';
  }
}

int ObBasicSessionInfo::set_flt_trace_id(ObString trace_id)
{
  int ret = OB_SUCCESS;
  MEMSET(flt_trace_id_, 0x00, common::OB_MAX_UUID_LENGTH + 1);
  flt_trace_id_[0] = 0xFF;
  MEMCPY(flt_trace_id_+1, trace_id.ptr(), common::OB_MAX_UUID_LENGTH);
  return ret;
}

int ObBasicSessionInfo::set_flt_span_id(ObString span_id)
{
  int ret = OB_SUCCESS;
  MEMSET(flt_span_id_, 0x00, common::OB_MAX_UUID_LENGTH + 1);
  flt_span_id_[0] = 0xFF;
  MEMCPY(flt_span_id_+1, span_id.ptr(), common::OB_MAX_UUID_LENGTH);
  return ret;
}

void ObBasicSessionInfo::get_flt_trace_id(ObString &trace_id) const
{
  if (flt_trace_id_[0] == '\0') {
    trace_id.reset();
  } else {
    trace_id.assign(const_cast<char *>(&flt_trace_id_[1]), common::OB_MAX_UUID_LENGTH);
  }
}

void ObBasicSessionInfo::get_flt_span_id(ObString &span_id) const
{
  if (flt_span_id_[0] == '\0') {
    span_id.reset();
  } else {
    span_id.assign(const_cast<char *>(&flt_span_id_[1]), common::OB_MAX_UUID_LENGTH);
  }
}

ObObjType ObBasicSessionInfo::get_sys_variable_type(const ObString &var_name) const
{
  int ret = OB_SUCCESS;
  ObObjType obj_type = ObMaxType;
  ObBasicSysVar *val = NULL;
  if (OB_FAIL(inner_get_sys_var(var_name, val))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(var_name));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(var_name));
  } else {
    obj_type = val->get_data_type();
  }
  return obj_type;
}

// select @@XXX的时候meta data中的type
ObObjType ObBasicSessionInfo::get_sys_variable_meta_type(const ObString &var_name) const
{
  int ret = OB_SUCCESS;
  ObObjType obj_type = ObMaxType;
  ObBasicSysVar *val = NULL;
  if (OB_FAIL(inner_get_sys_var(var_name, val))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(var_name));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(var_name));
  } else {
    obj_type = val->get_meta_type();
  }
  return obj_type;
}

#define PROCESS_SESSION_INT_VARIABLE(sys_var)                                             \
    do {                                                                                  \
      ObArenaAllocator allocator(ObModIds::OB_SQL_SESSION);                             \
      int64_t val_int = 0;                                                                    \
      ObCastCtx cast_ctx(&allocator, NULL, CM_NONE, CS_TYPE_INVALID);                   \
      EXPR_GET_INT64_V2(val, val_int);                                                    \
      if (OB_SUCC(ret)) {                                                            \
        sys_var = val_int;                                                                \
      }                                                                                   \
    } while(0)

OB_INLINE int ObBasicSessionInfo::process_session_variable(ObSysVarClassType var, const ObObj &val,
    const bool check_timezone_valid/*true*/, const bool is_update_sys_var/*false*/)
{
  int ret = OB_SUCCESS;
  switch (var) {
    case SYS_VAR_OB_LOG_LEVEL: {
      OZ (process_session_log_level(val), val);
      break;
    }
    case SYS_VAR_OB_COMPATIBILITY_MODE: {
      OZ (process_session_compatibility_mode_value(val), val);
      break;
    }
    case SYS_VAR_SQL_MODE: {
      OZ (process_session_sql_mode_value(val), val);
      break;
    }
    case SYS_VAR_TIME_ZONE: {
      OZ (process_session_time_zone_value(val, check_timezone_valid));
      break;
    }
    case SYS_VAR_ERROR_ON_OVERLAP_TIME: {
      OZ (process_session_overlap_time_value(val));
      break;
    }
    case SYS_VAR_WAIT_TIMEOUT: {
      LockGuard lock_guard(thread_data_mutex_);
      PROCESS_SESSION_INT_VARIABLE(thread_data_.wait_timeout_);
      break;
    }
    case SYS_VAR_DEBUG_SYNC: {
      const bool is_global = false;
      ret = process_session_debug_sync(val, is_global, is_update_sys_var);
      break;
    }
    case SYS_VAR_OB_GLOBAL_DEBUG_SYNC: {
      const bool is_global = true;
      ret = process_session_debug_sync(val, is_global, is_update_sys_var);
      break;
    }
    case SYS_VAR_OB_READ_CONSISTENCY: {
      int64_t consistency = 0;
      PROCESS_SESSION_INT_VARIABLE(consistency);
      if (OB_SUCC(ret)) {
        consistency_level_ = static_cast<ObConsistencyLevel>(consistency);
      }
      break;
    }
    case SYS_VAR_AUTO_INCREMENT_INCREMENT: {
      uint64_t uint_val = 0;
      OZ (val.get_uint64(uint_val), val);
      OX (sys_vars_cache_.set_auto_increment_increment(uint_val));
      break;
    }
    case SYS_VAR_SQL_THROTTLE_CURRENT_PRIORITY: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_sql_throttle_current_priority(int_val));
      break;
    }
    case SYS_VAR_OB_LAST_SCHEMA_VERSION: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_last_schema_version(int_val));
      break;
    }
    case SYS_VAR_SQL_SELECT_LIMIT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_sql_select_limit(int_val));
      break;
    }
    case SYS_VAR_AUTO_INCREMENT_OFFSET: {
      uint64_t uint_val = 0;
      OZ (val.get_uint64(uint_val), val);
      OX (sys_vars_cache_.set_auto_increment_offset(uint_val));
      break;
    }
    case SYS_VAR_LAST_INSERT_ID: {
      uint64_t uint_val = 0;
      OZ (val.get_uint64(uint_val), val);
      OX (sys_vars_cache_.set_last_insert_id(uint_val));
      break;
    }
    case SYS_VAR_BINLOG_ROW_IMAGE: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_binlog_row_image(int_val));
      break;
    }
    case SYS_VAR_FOREIGN_KEY_CHECKS: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_foreign_key_checks(int_val));
      break;
    }
    case SYS_VAR_DEFAULT_PASSWORD_LIFETIME: {
      uint64_t uint_val = 0;
      OZ (val.get_uint64(uint_val), val);
      OX (sys_vars_cache_.set_default_password_lifetime(uint_val));
      break;
    }
    case SYS_VAR_TX_ISOLATION : {
      ObString str_val;
      ObTxIsolationLevel isolation = ObTxIsolationLevel::INVALID;
      OZ (val.get_string(str_val));
      OX (isolation = tx_isolation_from_str(str_val));
      OV (isolation != ObTxIsolationLevel::INVALID, OB_ERR_UNEXPECTED,
          str_val, isolation);
      OX (sys_vars_cache_.set_tx_isolation(isolation));
      break;
    }
    case SYS_VAR_TX_READ_ONLY: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_tx_read_only(int_val != 0));
      break;
    }
    case SYS_VAR_OB_ENABLE_PLAN_CACHE: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_enable_plan_cache(int_val != 0));
      break;
    }
    case SYS_VAR_OPTIMIZER_USE_SQL_PLAN_BASELINES: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_optimizer_use_sql_plan_baselines(int_val != 0));
      break;
    }
    case SYS_VAR_OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_optimizer_capture_sql_plan_baselines(int_val != 0));
      break;
    }
    case SYS_VAR_IS_RESULT_ACCURATE: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_is_result_accurate(int_val != 0));
      break;
    }
    case SYS_VAR_OB_ENABLE_TRANSMISSION_CHECKSUM: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_enable_transmission_checksum(int_val != 0));
      break;
    }
    case SYS_VAR_CHARACTER_SET_RESULTS: {
      int64_t coll_int64 = 0;
      // 无效的character type，用户获取过程中，也需要保证返回NULL
      if (val.is_null()) {
        OX (sys_vars_cache_.set_character_set_results(CHARSET_INVALID));
      } else if (OB_FAIL(val.get_int(coll_int64))) {
        LOG_WARN("fail to get int from value", K(val), K(ret));
      } else if (OB_UNLIKELY(false == ObCharset::is_valid_collation(coll_int64))) {
        // 这里不设置错误码
        LOG_WARN("invalid collation", K(coll_int64), K(val));
        OX (sys_vars_cache_.set_character_set_results(CHARSET_INVALID));
      } else {
        OX (sys_vars_cache_.set_character_set_results(
            ObCharset::charset_type_by_coll(static_cast<ObCollationType>(coll_int64))));
      }
      break;
    }
    case SYS_VAR_CHARACTER_SET_CONNECTION: {
      int64_t coll_int64 = 0;
      // 无效的character type，用户获取过程中，也需要保证返回NULL
      if (val.is_null()) {
        OX (sys_vars_cache_.set_character_set_connection(CHARSET_INVALID));
      } else if (OB_FAIL(val.get_int(coll_int64))) {
        LOG_WARN("fail to get int from value", K(val), K(ret));
      } else if (OB_UNLIKELY(false == ObCharset::is_valid_collation(coll_int64))) {
        // 这里不设置错误码
        LOG_WARN("invalid collation", K(coll_int64), K(val));
        OX (sys_vars_cache_.set_character_set_connection(CHARSET_INVALID));
      } else {
        OX (sys_vars_cache_.set_character_set_connection(
            ObCharset::charset_type_by_coll(static_cast<ObCollationType>(coll_int64))));
      }
      break;
    }
    case SYS_VAR_OB_ENABLE_JIT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_enable_jit(static_cast<ObJITEnableMode>(int_val)));
      break;
    }
    case SYS_VAR_CURSOR_SHARING: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_cursor_sharing_mode(static_cast<ObCursorSharingMode>(int_val)));
      break;
    }
    case SYS_VAR_OB_ENABLE_SQL_AUDIT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_enable_sql_audit(int_val != 0));
      break;
    }
    case SYS_VAR_NLS_LENGTH_SEMANTICS: {
      ObString str_val;
      ObLengthSemantics nls_length_semantics = LS_BYTE;
      OZ (val.get_string(str_val));
      OX (nls_length_semantics = get_length_semantics(str_val));
      OV (nls_length_semantics != LS_INVALIED, OB_ERR_UNEXPECTED, nls_length_semantics);
      OX (sys_vars_cache_.set_nls_length_semantics(nls_length_semantics));
      break;
    }
    case SYS_VAR_AUTOCOMMIT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_autocommit(int_val != 0));
      break;
    }
    case SYS_VAR_OB_ENABLE_SHOW_TRACE: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_enable_trace_log(int_val != 0));
      break;
    }
    case SYS_VAR_OB_ORG_CLUSTER_ID: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_org_cluster_id(int_val));
      break;
    }
    case SYS_VAR_OB_QUERY_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_query_timeout(int_val));
      break;
    }
    case SYS_VAR_OB_PL_BLOCK_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_pl_block_timeout(int_val));
      break;
    }
    case SYS_VAR_PLSQL_CCFLAGS: {
      ObString plsql_ccflags;
      OZ (val.get_string(plsql_ccflags));
      OX (sys_vars_cache_.set_plsql_ccflags(plsql_ccflags));
      break;
    }
    case SYS_VAR_OB_TRX_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_trx_timeout(int_val));
      break;
    }
    case SYS_VAR_OB_TRX_IDLE_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_trx_idle_timeout(int_val));
      break;
    }
    case SYS_VAR_OB_TRX_LOCK_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_ob_trx_lock_timeout(int_val));
      break;
    }
    case SYS_VAR_COLLATION_CONNECTION: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache_.set_collation_connection(int_val));
      break;
    }
    case SYS_VAR_TIMESTAMP: {
      //系统变脸timestamp默认值为0，是number类型, 设置单位是s。
      //当该系统变量设置为非0后, 则内部now()等时间函数会使用设置的值。
      //由于设置的单位是s, 内部是用us为单位的int64描述, 如果是用设置的
      //timestamp, 会先将设置的量转为us并四舍五入
      if (val.get_number().is_zero()) {
        sys_vars_cache_.set_timestamp(0);
      } else {
        const ObObj *res_obj = NULL;
        ObArenaAllocator allocator(common::ObModIds::OB_SQL_EXPR_CALC);
        number::ObNumber value;
        number::ObNumber unit;
        if (OB_FAIL(unit.from(static_cast<int64_t>(USECS_PER_SEC * 10),
                              allocator))) {
          LOG_WARN("failed to get the number", K(ret));
        } else if (OB_FAIL(val.get_number().mul(unit, value, allocator))) {
          LOG_WARN("failed to get the result of timestamp to microsecond", K(ret));
        } else {
          ObObj param_obj;
          param_obj.set_number(value);
          ObCollationType cast_coll_type = static_cast<ObCollationType>(
                                           get_local_collation_connection());
          //const ObDataTypeCastParams dtc_params(TZ_INFO(this), GET_NLS_FORMATS(this), get_nls_collation(), get_nls_collation_nation());;
          ObDataTypeCastParams dtc_params = get_dtc_params();
          ObCastCtx cast_ctx(&allocator,
                             &dtc_params,
                             0, /*number_int 该变量无用*/
                             CM_NONE,
                             cast_coll_type,
                             NULL /* time zone info */);
          EXPR_CAST_OBJ_V2(ObIntType, param_obj, res_obj);
          if (OB_SUCC(ret)) {
            if (OB_ISNULL(res_obj)) {
              ret = OB_ERR_UNEXPECTED;
              LOG_WARN("result obj is null");
            } else {
              //处理四舍五入 int64_t 最大值为9,223,372,036,854,775,807
              //而9999-12-31到1970之间差值为2,469,899,520,000,000,000因此足够转换
              sys_vars_cache_.set_timestamp((res_obj->get_int() + 5) / 10);
            }
          } else {
            LOG_WARN("failed to convert the number to int", K(ret));
          }
        }
      }
      break;
    }
    case SYS_VAR_NLS_ISO_CURRENCY: {
      ObString country_str;
      ObString currency_str;
      if (OB_FAIL(val.get_string(country_str))) {
        LOG_WARN("fail to get iso_nls_currency str value", K(ret), K(var));
      } else if (OB_FAIL(IsoCurrencyUtils::get_currency_by_country_name(country_str,
                 currency_str))) {
        ret = OB_ERR_WRONG_VALUE_FOR_VAR;
        LOG_WARN("failed to get currency by country name", K(ret));
      } else {
        sys_vars_cache_.set_iso_nls_currency(currency_str);
      }
      break;
    }
    case SYS_VAR_NLS_DATE_FORMAT:
    case SYS_VAR_NLS_TIMESTAMP_FORMAT:
    case SYS_VAR_NLS_TIMESTAMP_TZ_FORMAT: {
      ObString format;
      if (OB_FAIL(val.get_string(format))) {
        LOG_WARN("fail to get nls_date_format str value", K(ret), K(var));
      } else {
        int64_t nls_enum = ObNLSFormatEnum::NLS_DATE;
        ObDTMode mode = DT_TYPE_DATETIME;
        if (SYS_VAR_NLS_TIMESTAMP_FORMAT == var) {
          mode |= DT_TYPE_ORACLE;
          nls_enum = ObNLSFormatEnum::NLS_TIMESTAMP;
        } else if (SYS_VAR_NLS_TIMESTAMP_TZ_FORMAT == var) {
          mode |= DT_TYPE_ORACLE;
          mode |= DT_TYPE_TIMEZONE;
          nls_enum = ObNLSFormatEnum::NLS_TIMESTAMP_TZ;
        }
        ObSEArray<ObDFMElem, ObDFMUtil::COMMON_ELEMENT_NUMBER> dfm_elems;
        ObFixedBitSet<OB_DEFAULT_BITSET_SIZE_FOR_DFM> elem_flags;
        //1. parse and check semantic of format string
        if (OB_FAIL(ObDFMUtil::parse_datetime_format_string(format, dfm_elems,
                                                            false/* support double-quotes */))) {
          LOG_WARN("fail to parse oracle datetime format string", K(ret), K(format));
        } else if (OB_FAIL(ObDFMUtil::check_semantic(dfm_elems, elem_flags, mode))) {
          LOG_WARN("check semantic of format string failed", K(ret), K(format));
        } else {
          switch (nls_enum) {
          case ObNLSFormatEnum::NLS_DATE:
            sys_vars_cache_.set_nls_date_format(format);
            break;
          case ObNLSFormatEnum::NLS_TIMESTAMP:
            sys_vars_cache_.set_nls_timestamp_format(format);
            break;
          case ObNLSFormatEnum::NLS_TIMESTAMP_TZ:
            sys_vars_cache_.set_nls_timestamp_tz_format(format);
            break;
          default:
            break;
          }
        }
        LOG_DEBUG("succ to set SYS_VAR_NLS_FORMAT", K(ret), K(var), K(nls_enum), K(format));
      }
      break;
    }
    case SYS_VAR_NLS_NCHAR_CHARACTERSET:
    case SYS_VAR_NLS_CHARACTERSET: {
      ObString str_val;
      ObCharsetType charset = CHARSET_INVALID;
      ObCollationType collation = CS_TYPE_INVALID;
      OZ (val.get_string(str_val), val);
      OX (charset = ObCharset::charset_type_by_name_oracle(str_val));
      OX (collation = ObCharset::get_default_collation_oracle(charset));
      OV (ObCharset::is_valid_charset(charset) && ObCharset::is_valid_collation(collation),
          OB_ERR_INVALID_CHARACTER_STRING, str_val, charset, collation);
      if (var == SYS_VAR_NLS_CHARACTERSET) {
        OX (sys_vars_cache_.set_nls_collation(collation));
      } else {
        OX (sys_vars_cache_.set_nls_nation_collation(collation));
      }
      break;
    }
    case SYS_VAR__OB_OLS_POLICY_SESSION_LABELS: {
      ObString serialized_data;
      if (OB_FAIL(val.get_string(serialized_data))) {
        LOG_WARN("fail to get str value", K(ret), K(var));
      } else if (OB_FAIL(ObLabelSeResolver::deserialize_session_labels(serialized_data,
                                                                       labels_))) {
        LOG_WARN("fail to deserialize_session_labels", K(ret), K(serialized_data));
      }
      break;
    }
    case SYS_VAR_OB_TRACE_INFO: {
      ObString trace_info;
      if (OB_FAIL(val.get_string(trace_info))) {
        LOG_WARN("fail to get str value", K(ret), K(var));
      } else {
        sys_vars_cache_.set_ob_trace_info(trace_info);
      }
      break;
    }
    default: {
      //do nothing
    }
  }
  return ret;
}

// for debug purpose, not used for now
int ObBasicSessionInfo::dump_all_sys_vars() const
{
  int ret = OB_SUCCESS;
  int64_t store_idx = OB_INVALID_INDEX_INT64;
  ObBasicSessionInfo::SysVarsCache sys_vars_cache;
  int64_t var_amount = ObSysVariables::get_amount();
  for (int64_t i = 0; OB_SUCC(ret) && i < var_amount; ++i) {
    store_idx = ObSysVarsToIdxMap::get_store_idx((int64_t)ObSysVariables::get_sys_var_id(i));
    OV (0 <= store_idx && store_idx < ObSysVarFactory::ALL_SYS_VARS_COUNT);
    OV (OB_NOT_NULL(sys_vars_[store_idx]));
    if (OB_SUCC(ret)) {
      LOG_INFO("DUMP sys vars", K(i), K(store_idx), KP(this), KP(sys_vars_[store_idx]), "info", *sys_vars_[store_idx]);
    }
  }
  return ret;
}

int ObBasicSessionInfo::init_sys_vars_cache_base_values()
{
  int ret = OB_SUCCESS;
  int64_t store_idx = OB_INVALID_INDEX_INT64;
  ObBasicSessionInfo::SysVarsCache sys_vars_cache;
  int64_t var_amount = ObSysVariables::get_amount();
  for (int64_t i = 0; OB_SUCC(ret) && i < var_amount; ++i) {
    store_idx = ObSysVarsToIdxMap::get_store_idx((int64_t)ObSysVariables::get_sys_var_id(i));
    OX (fill_sys_vars_cache_base_value(
            ObSysVariables::get_sys_var_id(i),
            sys_vars_cache,
            ObSysVariables::get_default_value(store_idx) ));
  }
  return ret;
}

int ObBasicSessionInfo::fill_sys_vars_cache_base_value(
    ObSysVarClassType var,
    ObBasicSessionInfo::SysVarsCache &sys_vars_cache,
    const ObObj &val)
{
  int ret = OB_SUCCESS;
  switch (var) {
    case SYS_VAR_SQL_MODE: {
      ObSQLMode sql_mode = static_cast<ObSQLMode>(val.get_uint64());
      ObSQLMode real_sql_mode = (sql_mode & (~ALL_SMO_COMPACT_MODE)) |
          (sys_vars_cache.get_sql_mode() & ALL_SMO_COMPACT_MODE);
      sys_vars_cache.set_base_sql_mode(real_sql_mode);
      break;
    }
    case SYS_VAR_OB_COMPATIBILITY_MODE: {
      uint64_t uint_val = 0;
      ObCompatibilityMode comp_mode = static_cast<ObCompatibilityMode>(val.get_uint64());
      ObSQLMode real_sql_mode = ob_compatibility_mode_to_sql_mode(comp_mode) |
          (sys_vars_cache.get_sql_mode() & ~ALL_SMO_COMPACT_MODE);
      sys_vars_cache.set_base_sql_mode(real_sql_mode);
      break;
    }
    case SYS_VAR_AUTO_INCREMENT_INCREMENT: {
      uint64_t uint_val = 0;
      OZ (val.get_uint64(uint_val), val);
      OX (sys_vars_cache.set_base_auto_increment_increment(uint_val));
      break;
    }
    case SYS_VAR_SQL_THROTTLE_CURRENT_PRIORITY: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_sql_throttle_current_priority(int_val));
      break;
    }
    case SYS_VAR_OB_LAST_SCHEMA_VERSION: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_last_schema_version(int_val));
      break;
    }
    case SYS_VAR_SQL_SELECT_LIMIT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_sql_select_limit(int_val));
      break;
    }
    case SYS_VAR_AUTO_INCREMENT_OFFSET: {
      uint64_t uint_val = 0;
      OZ (val.get_uint64(uint_val), val);
      OX (sys_vars_cache.set_base_auto_increment_offset(uint_val));
      break;
    }
    case SYS_VAR_LAST_INSERT_ID: {
      uint64_t uint_val = 0;
      OZ (val.get_uint64(uint_val), val);
      OX (sys_vars_cache.set_base_last_insert_id(uint_val));
      break;
    }
    case SYS_VAR_BINLOG_ROW_IMAGE: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_binlog_row_image(int_val));
      break;
    }
    case SYS_VAR_FOREIGN_KEY_CHECKS: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_foreign_key_checks(int_val));
      break;
    }
    case SYS_VAR_DEFAULT_PASSWORD_LIFETIME: {
      uint64_t uint_val = 0;
      OZ (val.get_uint64(uint_val), val);
      OX (sys_vars_cache.set_base_default_password_lifetime(uint_val));
      break;
    }
    case SYS_VAR_TX_ISOLATION : {
      ObString str_val;
      ObTxIsolationLevel isolation = ObTxIsolationLevel::INVALID;
      OZ (val.get_string(str_val));
      OX (isolation = tx_isolation_from_str(str_val));
      OV (isolation != ObTxIsolationLevel::INVALID, OB_ERR_UNEXPECTED,
          str_val, isolation);
      OX (sys_vars_cache.set_base_tx_isolation(isolation));
      break;
    }
    case SYS_VAR_TX_READ_ONLY: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_tx_read_only(int_val != 0));
      break;
    }
    case SYS_VAR_OB_ENABLE_PLAN_CACHE: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_enable_plan_cache(int_val != 0));
      break;
    }
    case SYS_VAR_OPTIMIZER_USE_SQL_PLAN_BASELINES: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_optimizer_use_sql_plan_baselines(int_val != 0));
      break;
    }
    case SYS_VAR_OPTIMIZER_CAPTURE_SQL_PLAN_BASELINES: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_optimizer_capture_sql_plan_baselines(int_val != 0));
      break;
    }
    case SYS_VAR_IS_RESULT_ACCURATE: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_is_result_accurate(int_val != 0));
      break;
    }
    case SYS_VAR_OB_ENABLE_TRANSMISSION_CHECKSUM: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_enable_transmission_checksum(int_val != 0));
      break;
    }
    case SYS_VAR_CHARACTER_SET_RESULTS: {
      int64_t coll_int64 = 0;
      // 无效的character type，用户获取过程中，也需要保证返回NULL
      if (val.is_null()) {
        OX (sys_vars_cache.set_base_character_set_results(CHARSET_INVALID));
      } else if (OB_FAIL(val.get_int(coll_int64))) {
        LOG_WARN("fail to get int from value", K(val), K(ret));
      } else if (OB_UNLIKELY(false == ObCharset::is_valid_collation(coll_int64))) {
        // 这里不设置错误码
        LOG_WARN("invalid collation", K(coll_int64), K(val));
        OX (sys_vars_cache.set_base_character_set_results(CHARSET_INVALID));
      } else {
        OX (sys_vars_cache.set_base_character_set_results(
            ObCharset::charset_type_by_coll(static_cast<ObCollationType>(coll_int64))));
      }
      break;
    }
    case SYS_VAR_CHARACTER_SET_CONNECTION: {
      int64_t coll_int64 = 0;
      // 无效的character type，用户获取过程中，也需要保证返回NULL
      if (val.is_null()) {
        OX (sys_vars_cache.set_base_character_set_connection(CHARSET_INVALID));
      } else if (OB_FAIL(val.get_int(coll_int64))) {
        LOG_WARN("fail to get int from value", K(val), K(ret));
      } else if (OB_UNLIKELY(false == ObCharset::is_valid_collation(coll_int64))) {
        // 这里不设置错误码
        LOG_WARN("invalid collation", K(coll_int64), K(val));
        OX (sys_vars_cache.set_base_character_set_connection(CHARSET_INVALID));
      } else {
        OX (sys_vars_cache.set_base_character_set_connection(
            ObCharset::charset_type_by_coll(static_cast<ObCollationType>(coll_int64))));
      }
      break;
    }
    case SYS_VAR_OB_ENABLE_JIT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_enable_jit(static_cast<ObJITEnableMode>(int_val)));
      break;
    }
    case SYS_VAR_CURSOR_SHARING: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_cursor_sharing_mode(static_cast<ObCursorSharingMode>(int_val)));
      break;
    }
    case SYS_VAR_OB_ENABLE_SQL_AUDIT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_enable_sql_audit(int_val != 0));
      break;
    }
    case SYS_VAR_NLS_LENGTH_SEMANTICS: {
      ObString str_val;
      ObLengthSemantics nls_length_semantics = LS_BYTE;
      OZ (val.get_string(str_val));
      OX (nls_length_semantics = get_length_semantics(str_val));
      OV (nls_length_semantics != LS_INVALIED, OB_ERR_UNEXPECTED, nls_length_semantics);
      OX (sys_vars_cache.set_base_nls_length_semantics(nls_length_semantics));
      break;
    }
    case SYS_VAR_AUTOCOMMIT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_autocommit(int_val != 0));
      break;
    }
    case SYS_VAR_OB_ENABLE_SHOW_TRACE: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_enable_trace_log(int_val != 0));
      break;
    }
    case SYS_VAR_OB_ORG_CLUSTER_ID: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_org_cluster_id(int_val));
      break;
    }
    case SYS_VAR_OB_QUERY_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_query_timeout(int_val));
      break;
    }
    case SYS_VAR_OB_PL_BLOCK_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_pl_block_timeout(int_val));
      break;
    }
    case SYS_VAR_PLSQL_CCFLAGS: {
      ObString plsql_ccflags;
      OZ (val.get_string(plsql_ccflags));
      OX (sys_vars_cache.set_base_plsql_ccflags(plsql_ccflags));
      break;
    }
    case SYS_VAR_OB_TRX_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_trx_timeout(int_val));
      break;
    }
    case SYS_VAR_OB_TRX_IDLE_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_trx_idle_timeout(int_val));
      break;
    }
    case SYS_VAR_OB_TRX_LOCK_TIMEOUT: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_ob_trx_lock_timeout(int_val));
      break;
    }
    case SYS_VAR_COLLATION_CONNECTION: {
      int64_t int_val = 0;
      OZ (val.get_int(int_val), val);
      OX (sys_vars_cache.set_base_collation_connection(int_val));
      break;
    }
    case SYS_VAR_TIMESTAMP: {
      //系统变脸timestamp默认值为0，是number类型, 设置单位是s。
      //当该系统变量设置为非0后, 则内部now()等时间函数会使用设置的值。
      //由于设置的单位是s, 内部是用us为单位的int64描述, 如果是用设置的
      //timestamp, 会先将设置的量转为us并四舍五入
      if (val.get_number().is_zero()) {
        sys_vars_cache.set_base_timestamp(0);
      } else {
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("unexpected default timestamp value. must be zero", K(ret), K(val));
      }
      break;
    }
    case SYS_VAR_NLS_ISO_CURRENCY: {
      ObString country_str;
      ObString currency_str;
      if (OB_FAIL(val.get_string(country_str))) {
        LOG_WARN("fail to get iso_nls_currency str value", K(ret), K(var));
      } else if (OB_FAIL(IsoCurrencyUtils::get_currency_by_country_name(country_str,
                 currency_str))) {
        ret = OB_ERR_WRONG_VALUE_FOR_VAR;
        LOG_WARN("failed to get currency by country name", K(ret));
      } else {
        sys_vars_cache.set_base_iso_nls_currency(currency_str);
      }
      break;
    }
    case SYS_VAR_NLS_DATE_FORMAT:
    case SYS_VAR_NLS_TIMESTAMP_FORMAT:
    case SYS_VAR_NLS_TIMESTAMP_TZ_FORMAT: {
      ObString format;
      if (OB_FAIL(val.get_string(format))) {
        LOG_WARN("fail to get nls_date_format str value", K(ret), K(var));
      } else {
        int64_t nls_enum = ObNLSFormatEnum::NLS_DATE;
        ObDTMode mode = DT_TYPE_DATETIME;
        if (SYS_VAR_NLS_TIMESTAMP_FORMAT == var) {
          mode |= DT_TYPE_ORACLE;
          nls_enum = ObNLSFormatEnum::NLS_TIMESTAMP;
        } else if (SYS_VAR_NLS_TIMESTAMP_TZ_FORMAT == var) {
          mode |= DT_TYPE_ORACLE;
          mode |= DT_TYPE_TIMEZONE;
          nls_enum = ObNLSFormatEnum::NLS_TIMESTAMP_TZ;
        }
        ObSEArray<ObDFMElem, ObDFMUtil::COMMON_ELEMENT_NUMBER> dfm_elems;
        ObFixedBitSet<OB_DEFAULT_BITSET_SIZE_FOR_DFM> elem_flags;
        //1. parse and check semantic of format string
        if (OB_FAIL(ObDFMUtil::parse_datetime_format_string(format, dfm_elems,
                                                            false/* support double-quotes */))) {
          LOG_WARN("fail to parse oracle datetime format string", K(ret), K(format));
        } else if (OB_FAIL(ObDFMUtil::check_semantic(dfm_elems, elem_flags, mode))) {
          LOG_WARN("check semantic of format string failed", K(ret), K(format));
        } else {
          switch (nls_enum) {
          case ObNLSFormatEnum::NLS_DATE:
            sys_vars_cache.set_base_nls_date_format(format);
            break;
          case ObNLSFormatEnum::NLS_TIMESTAMP:
            sys_vars_cache.set_base_nls_timestamp_format(format);
            break;
          case ObNLSFormatEnum::NLS_TIMESTAMP_TZ:
            sys_vars_cache.set_base_nls_timestamp_tz_format(format);
            break;
          default:
            break;
          }
        }
        LOG_DEBUG("succ to set SYS_VAR_NLS_FORMAT", K(ret), K(var), K(nls_enum), K(format));
      }
      break;
    }
    case SYS_VAR_NLS_NCHAR_CHARACTERSET:
    case SYS_VAR_NLS_CHARACTERSET: {
      ObString str_val;
      ObCharsetType charset = CHARSET_INVALID;
      ObCollationType collation = CS_TYPE_INVALID;
      OZ (val.get_string(str_val), val);
      OX (charset = ObCharset::charset_type_by_name_oracle(str_val));
      OX (collation = ObCharset::get_default_collation_oracle(charset));
      OV (ObCharset::is_valid_charset(charset) && ObCharset::is_valid_collation(collation),
          OB_ERR_INVALID_CHARACTER_STRING, str_val, charset, collation);
      if (var == SYS_VAR_NLS_CHARACTERSET) {
        OX (sys_vars_cache.set_base_nls_collation(collation));
      } else {
        OX (sys_vars_cache.set_base_nls_nation_collation(collation));
      }
      break;
    }
    case SYS_VAR_OB_TRACE_INFO: {
      ObString trace_info;
      if (OB_FAIL(val.get_string(trace_info))) {
        LOG_WARN("fail to get str value", K(ret), K(var));
      } else {
        sys_vars_cache.set_base_ob_trace_info(trace_info);
      }
      break;
    }
    default: {
      //do nothing
    }
  }
  return ret;
}


int ObBasicSessionInfo::process_session_variable_fast()
{
  int ret = OB_SUCCESS;
  int64_t store_idx = -1;
  // SYS_VAR_OB_LOG_LEVEL
  OZ (ObSysVarFactory::calc_sys_var_store_idx(SYS_VAR_OB_LOG_LEVEL, store_idx));
  OV (ObSysVarFactory::is_valid_sys_var_store_idx(store_idx));
  OZ (process_session_log_level(sys_vars_[store_idx]->get_value()));
  // SYS_VAR_DEBUG_SYNC
  OZ (ObSysVarFactory::calc_sys_var_store_idx(SYS_VAR_DEBUG_SYNC, store_idx));
  OV (ObSysVarFactory::is_valid_sys_var_store_idx(store_idx));
  OZ (process_session_debug_sync(sys_vars_[store_idx]->get_value(), false, false));
  // SYS_VAR_OB_GLOBAL_DEBUG_SYNC
  OZ (ObSysVarFactory::calc_sys_var_store_idx(SYS_VAR_OB_GLOBAL_DEBUG_SYNC, store_idx));
  OV (ObSysVarFactory::is_valid_sys_var_store_idx(store_idx));
  OZ (process_session_debug_sync(sys_vars_[store_idx]->get_value(), true, false));
  // SYS_VAR_OB_READ_CONSISTENCY
  // 这个系统变量对应consistency_level_，该属性只能通过常规途径修改，所以适合加入sys_vars_cache_，
  // 但这样涉及到的相关修改比较大，稳妥起见保留现有的序列化操作，只在本接口里执行，保证主线程正确初始化。
  OZ (ObSysVarFactory::calc_sys_var_store_idx(SYS_VAR_OB_READ_CONSISTENCY, store_idx));
  OV (ObSysVarFactory::is_valid_sys_var_store_idx(store_idx));
  if (OB_SUCC(ret)) {
    const ObObj &val = sys_vars_[store_idx]->get_value();
    int64_t consistency = 0;
    PROCESS_SESSION_INT_VARIABLE(consistency);
    OX (consistency_level_ = static_cast<ObConsistencyLevel>(consistency));
  }
  // SYS_VAR_WAIT_TIMEOUT
  {
    LockGuard lock_guard(thread_data_mutex_);
    get_int64_sys_var(SYS_VAR_WAIT_TIMEOUT, thread_data_.wait_timeout_);
  }

  // SYS_VAR_TIME_ZONE / SYS_VAR_ERROR_ON_OVERLAP_TIME
  // 这两个系统变量对应tz_info_wrap_，但该属性还有非系统变量方式的修改途径(update_timezone_info接口)，
  // 所以tz_info_wrap_不适合加入sys_vars_cache_，但需要序列化。
  // 主线程申请session时，会在process_single_stmt接口中调用update_timezone_info接口，所以也能得到恰当的初始化。
  OZ (reset_timezone());
  return ret;
}

int ObBasicSessionInfo::process_session_sql_mode_value(const ObObj &value)
{
  int ret = OB_SUCCESS;
  ObSQLMode sql_mode = 0;
  if (value.is_string_type()) {
    const ObString &sql_mode_str = value.get_string();
    if (OB_FAIL(ob_str_to_sql_mode(sql_mode_str, sql_mode))) {
      LOG_WARN("failed to get sql mode", K(sql_mode_str), K(value), K(ret));
    }
  } else if (ObUInt64Type == value.get_type()) {
    sql_mode = value.get_uint64();
  } else if (ObIntType == value.get_type()) {
    sql_mode = static_cast<ObSQLMode>(value.get_int());
  } else {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("invalid sql mode val type", K(value.get_type()), K(value), K(ret));
  }
  if (OB_FAIL(ret)) {
  } else if (!is_sql_mode_supported(sql_mode)) {
    ret = OB_NOT_SUPPORTED;
    LOG_USER_ERROR(OB_NOT_SUPPORTED, "Value for sql_mode");
    LOG_WARN("invalid sql mode val", K(value.get_type()), K(value), K(ret));
  } else {
    set_sql_mode(sql_mode);
  }
  return ret;
}

// 检查使用is_oracle_mode与compatibility_mode是否一致，如果不一致，则说明此处不能直接用is_oracle_mode替代
int ObBasicSessionInfo::check_compatibility_mode() const {
  int ret = OB_SUCCESS;
  ObCompatibilityMode mode = get_compatibility_mode();
  if (ORACLE_MODE == mode && is_oracle_mode()) {
  } else if (MYSQL_MODE == mode && is_mysql_mode()) {
  } else {
    // 有时mode还没有赋值，是OCEANBASE_MODE，所以这里暂时不强一致认为一定一样，但至少需要保证oracle一致
    if (ORACLE_MODE == mode && !is_oracle_mode()) {
      ret = OB_ERR_UNEXPECTED;
      LOG_ERROR("compatibility mode is not match", K(mode), K(is_oracle_mode()), K(lbt()), K(ret));
    }
  }
  return ret;
}

int ObBasicSessionInfo::process_session_compatibility_mode_value(const ObObj &value)
{
  int ret = OB_SUCCESS;
  ObCompatibilityMode comp_mode = ObCompatibilityMode::OCEANBASE_MODE;
  if (value.is_string_type()) {
    const ObString &comp_mode_str = value.get_string();
    if (comp_mode_str.case_compare("ORACLE")) {
      comp_mode = ObCompatibilityMode::ORACLE_MODE;
    } else if (comp_mode_str.case_compare("MYSQL")) {
      comp_mode = ObCompatibilityMode::MYSQL_MODE;
    } else {
      ret = OB_NOT_SUPPORTED;
      LOG_USER_ERROR(OB_NOT_SUPPORTED, "compatibility mode");
      LOG_WARN("not supported sql mode", K(ret), K(value), K(comp_mode_str));
    }
  } else if (ObUInt64Type == value.get_type()) {
    comp_mode = static_cast<ObCompatibilityMode>(value.get_uint64());
  } else if (ObIntType == value.get_type()) {
    comp_mode = static_cast<ObCompatibilityMode>(value.get_int());
  } else {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("invalid sql mode val type", K(value.get_type()), K(value), K(ret));
  }

  if (OB_SUCC(ret)) {
    set_compatibility_mode(comp_mode);
    LOG_DEBUG("set compatibility mode", K(ret), K(comp_mode), K(value), K(get_compatibility_mode()), K(lbt()));
  }
  return ret;
}

int ObBasicSessionInfo::process_session_time_zone_value(const ObObj &value,
                                                        const bool check_timezone_valid)
{
  int ret = OB_SUCCESS;
  ObString str_val;
  const bool is_oralce_mode = is_oracle_compatible();
  if (OB_FAIL(value.get_string(str_val))) {
    LOG_WARN("fail to get string value", K(value), K(ret));
  } else if (OB_FAIL(set_time_zone(str_val, is_oralce_mode, check_timezone_valid))) {
    LOG_WARN("failed to set time zone", K(str_val), K(is_oralce_mode), "is_oracle_compatible", is_oracle_compatible(), K(ret));
  }
  return ret;
}

int ObBasicSessionInfo::process_session_overlap_time_value(const ObObj &value)
{
  int ret = OB_SUCCESS;
  if (OB_FAIL(tz_info_wrap_.set_error_on_overlap_time(value.get_bool()))) {
    LOG_WARN("fail to set error on overlap time", K(value), K(ret));
  }
  return ret;
}

int ObBasicSessionInfo::process_session_log_level(const ObObj &val)
{
  int ret = OB_SUCCESS;
  int32_t valid_length = 0;
  ObString val_str;
  if (OB_SUCC(val.get_varchar(val_str))) {
    if (0 == val_str.case_compare("disabled")) {
      log_id_level_map_valid_ = false;
      log_id_level_map_.reset_level();
    } else if (OB_FAIL(OB_LOGGER.parse_set(val_str.ptr(), val_str.length(), valid_length,
                                           log_id_level_map_))) {
      LOG_WARN("Failed to parse set log_level", K(ret), "log_level", val_str);
    } else {
      log_id_level_map_valid_ = true;
    }
  }
  return ret;
}

int ObBasicSessionInfo::process_session_debug_sync(const ObObj &val,
                                                   const bool is_global,
                                                   const bool is_update_sys_var)
{
  int ret = OB_SUCCESS;
  if (OB_SYS_TENANT_ID == tenant_id_ && GCONF.is_debug_sync_enabled()) {
    ObString debug_sync;
    if (OB_FAIL(val.get_varchar(debug_sync))) {
      LOG_WARN("varchar expected", K(ret));
    } else {
      if (!debug_sync.empty()) {
        if (OB_FAIL(GDS.add_debug_sync(debug_sync, is_global, debug_sync_actions_))) {
          LOG_WARN("set debug sync string failed", K(debug_sync), K(ret));
        }
      }
    }
  } else {
    if (is_update_sys_var) {
      ret = OB_NOT_SUPPORTED;
      LOG_USER_ERROR(OB_NOT_SUPPORTED,
                    "Non-system tenant or debug_sync is turned off, set debug_sync is");
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_int64_sys_var(const ObSysVarClassType sys_var_id,
                                          int64_t &int64_val) const
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *val = NULL;
  if (OB_FAIL(inner_get_sys_var(sys_var_id, val))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(sys_var_id));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(sys_var_id));
  } else {
    int64_t int_val = 0;
    if (OB_FAIL(val->get_value().get_int(int_val))) {
      LOG_WARN("fail to get int from value", K(*val), K(ret));
    } else {
      int64_val = int_val;
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_uint64_sys_var(const ObSysVarClassType sys_var_id,
                                           uint64_t &uint64_val) const
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *val = NULL;
  if (OB_FAIL(inner_get_sys_var(sys_var_id, val))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(sys_var_id));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(sys_var_id));
  } else {
    uint64_t uint_val = 0;
    if (OB_FAIL(val->get_value().get_uint64(uint_val))) {
      LOG_ERROR("fail to get uint64 from value", K(*val), K(ret));
    } else {
      uint64_val = uint_val;
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_bool_sys_var(const ObSysVarClassType sys_var_id,
                                         bool &bool_val) const
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *val = NULL;
  if (OB_FAIL(inner_get_sys_var(sys_var_id, val))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(sys_var_id));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(sys_var_id));
  } else {
    int64_t int_val = 0;
    if (OB_SUCCESS != (ret = val->get_value().get_int(int_val))) {
      LOG_ERROR("fail to get int from value", K(*val), K(ret));
    } else {
      bool_val = (0 != int_val);
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_charset_sys_var(const ObSysVarClassType sys_var_id,
                                            ObCharsetType &cs_type) const
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *val = NULL;
  if (OB_FAIL(inner_get_sys_var(sys_var_id, val))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(sys_var_id));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret), K(sys_var_id));
  } else {
    int64_t coll_int64 = 0;
    if (val->get_value().is_null()) {
      cs_type = CHARSET_INVALID;
    } else if (OB_FAIL(val->get_value().get_int(coll_int64))) {
      LOG_ERROR("fail to get int from value", K(*val), K(ret));
    } else if (OB_UNLIKELY(false == ObCharset::is_valid_collation(coll_int64))) {
      LOG_ERROR("invalid collation", K(sys_var_id), K(coll_int64), K(*val));
    } else {
      cs_type = ObCharset::charset_type_by_coll(static_cast<ObCollationType>(coll_int64));
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_collation_sys_var(ObSysVarClassType sys_var_id,
                                              ObCollationType &coll_type) const
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *val = NULL;
  if (OB_FAIL(inner_get_sys_var(sys_var_id, val))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(sys_var_id));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get sys var, but sys var is NULL", K(ret));
  } else {
    int64_t coll_int64 = 0;
    if (OB_FAIL(val->get_value().get_int(coll_int64))) {
      LOG_ERROR("fail to get int from value", K(ret), K(*val));
    } else if (OB_UNLIKELY(false == ObCharset::is_valid_collation(coll_int64))) {
      LOG_ERROR("invalid collation", K(sys_var_id), K(coll_int64), K(*val));
    } else {
      coll_type = static_cast<ObCollationType>(coll_int64);
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_string_sys_var(ObSysVarClassType sys_var_id,
                                            ObString &str) const
{
  int ret = OB_SUCCESS;
  ObBasicSysVar *val = NULL;
  if (OB_FAIL(inner_get_sys_var(sys_var_id, val))) {
    LOG_WARN("fail to inner get sys var", K(ret), K(sys_var_id));
  } else if (OB_ISNULL(val)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("succ to inner get says var, but sys var is NULL", K(ret));
  } else {
    if (OB_FAIL(val->get_value().get_string(str))) {
      LOG_ERROR("fail to get int from value", K(ret), K(*val));
    }
  }
  return ret;
}

int ObBasicSessionInfo::if_aggr_pushdown_allowed(bool &aggr_pushdown_allowed) const
{
  return get_bool_sys_var(SYS_VAR_OB_ENABLE_AGGREGATION_PUSHDOWN, aggr_pushdown_allowed);
}

int ObBasicSessionInfo::is_use_transmission_checksum(bool &use_transmission_checksum) const
{
  use_transmission_checksum = sys_vars_cache_.get_ob_enable_transmission_checksum();
  return OB_SUCCESS;
}

int ObBasicSessionInfo::get_name_case_mode(ObNameCaseMode &case_mode) const
{
  int ret = OB_SUCCESS;
  int64_t int64_val = -1;
  if (OB_FAIL(get_sys_variable(SYS_VAR_LOWER_CASE_TABLE_NAMES, int64_val))) {
    LOG_WARN("failed to load sys param", "var_name", OB_SV_LOWER_CASE_TABLE_NAMES, K(ret));
  } else {
    int32_t value = static_cast<int32_t>(int64_val);
    if (value <= OB_NAME_CASE_INVALID || value >= OB_NAME_CASE_MAX) {
      ret = OB_ERR_UNEXPECTED;
      LOG_ERROR("invalid value", "var_name", OB_SV_LOWER_CASE_TABLE_NAMES, K(value), K(ret));
    } else {
      case_mode = static_cast<ObNameCaseMode>(value);
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_init_connect(ObString &str) const
{
  return get_string_sys_var(SYS_VAR_INIT_CONNECT, str);
}

int ObBasicSessionInfo::is_transformation_enabled(bool &transformation_enabled) const
{
  return get_bool_sys_var(SYS_VAR_OB_ENABLE_TRANSFORMATION, transformation_enabled);
}

int ObBasicSessionInfo::is_select_index_enabled(bool &select_index_enabled) const
{
  return get_bool_sys_var(SYS_VAR_OB_ENABLE_INDEX_DIRECT_SELECT, select_index_enabled);
}

void ObBasicSessionInfo::set_autocommit(bool autocommit)
{
  sys_vars_cache_.set_autocommit(autocommit);
}

int ObBasicSessionInfo::get_explicit_defaults_for_timestamp(
    bool &explicit_defaults_for_timestamp) const
{
  return get_bool_sys_var(SYS_VAR_EXPLICIT_DEFAULTS_FOR_TIMESTAMP,
                          explicit_defaults_for_timestamp);
}

int ObBasicSessionInfo::get_sql_auto_is_null(bool &sql_auto_is_null) const
{
  return get_bool_sys_var(SYS_VAR_SQL_AUTO_IS_NULL, sql_auto_is_null);
}

int ObBasicSessionInfo::get_div_precision_increment(int64_t &div_precision_increment) const
{
  int ret = get_int64_sys_var(SYS_VAR_DIV_PRECISION_INCREMENT, div_precision_increment);
  return ret;
}

int64_t ObBasicSessionInfo::get_query_timeout_ts() const
{
  return sys_vars_cache_.get_ob_query_timeout() + get_query_start_time();
}

int ObBasicSessionInfo::get_pl_block_timeout(int64_t &pl_block_timeout) const
{
  pl_block_timeout = sys_vars_cache_.get_ob_pl_block_timeout();
  return OB_SUCCESS;
}

int ObBasicSessionInfo::get_ob_read_consistency(int64_t &ob_read_consistency) const
{
  return get_int64_sys_var(SYS_VAR_OB_READ_CONSISTENCY, ob_read_consistency);
}

int ObBasicSessionInfo::get_group_concat_max_len(uint64_t &group_concat_max_len) const
{
  return get_uint64_sys_var(SYS_VAR_GROUP_CONCAT_MAX_LEN, group_concat_max_len);
}

int ObBasicSessionInfo::get_ob_interm_result_mem_limit(int64_t &ob_interm_result_mem_limit) const
{
  return get_int64_sys_var(SYS_VAR_OB_INTERM_RESULT_MEM_LIMIT, ob_interm_result_mem_limit);
}

// 参数max_allowed_pkt和net_buffer_len的命名之所以不为max_allowed_packet和net_buffer_length，
// 是为了规避lib/regex/include/mysql.h中的命名重复，使得编译能通过
int ObBasicSessionInfo::get_max_allowed_packet(int64_t &max_allowed_pkt) const
{
  return get_int64_sys_var(SYS_VAR_MAX_ALLOWED_PACKET, max_allowed_pkt);
}

int ObBasicSessionInfo::get_net_buffer_length(int64_t &net_buffer_len) const
{
  return get_int64_sys_var(SYS_VAR_NET_BUFFER_LENGTH, net_buffer_len);
}

////////////////////////////////////////////////////////////////
int ObBasicSessionInfo::replace_user_variables(const ObSessionValMap &user_var_map)
{
  int ret = OB_SUCCESS;
  if (user_var_map.size() > 0) {
    const sql::ObSessionValMap::VarNameValMap &new_map = user_var_map.get_val_map();
    for (sql::ObSessionValMap::VarNameValMap::const_iterator iter = new_map.begin();
         OB_SUCC(ret) && iter != new_map.end(); iter++) {
      const common::ObString &key = iter->first;
      const sql::ObSessionVariable &value = iter->second;
      if (OB_FAIL(replace_user_variable(key, value))) {
        LOG_WARN("fail to replace user var", K(ret), K(key), K(value));
      }
    }
  }
  return ret;
}

int ObBasicSessionInfo::replace_user_variable(const ObString &var, const ObSessionVariable &val)
{
  int ret = OB_SUCCESS;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid var name", K(var), K(ret));
  } else if (OB_FAIL(user_var_val_map_.set_refactored(var, val))) {
    LOG_ERROR("fail to add variable", K(var), K(ret));
  } else {
    if (is_track_session_info()) {
      if (OB_FAIL(track_user_var(var))) {
        LOG_WARN("fail to track user var", K(var), K(ret));
      }
    }
    if (OB_SUCC(ret)) {
      variables_last_modify_time_ = ObTimeUtility::current_time();
    }
  }
  return ret;
}

int ObBasicSessionInfo::remove_user_variable(const ObString &var)
{
  int ret = OB_SUCCESS;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
  } else if (OB_SUCCESS != user_var_val_map_.erase_refactored(var)) {
    ret = OB_ERR_USER_VARIABLE_UNKNOWN;
    LOG_WARN("unknown variable", K(var), K(ret));
  } else {
    variables_last_modify_time_ = ObTimeUtility::current_time();
  }
  return ret;
}

int ObBasicSessionInfo::get_user_variable(const ObString &var, ObSessionVariable &val) const
{
  int ret = OB_SUCCESS;
  if (var.empty()) {
   /* bugfix:https://work.aone.alibaba-inc.com/issue/37171897
    * select @; return NULL;
    * select @""; select @''; select @``; return NULL;
    */
   if (lib::is_oracle_mode()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
   }
  } else if (OB_SUCCESS != user_var_val_map_.get_refactored(var, val)) {
    ret = OB_ERR_USER_VARIABLE_UNKNOWN;
    LOG_WARN("unknown user variable", K(var), K(ret));
  } else {
  }
  return ret;
}

int ObBasicSessionInfo::get_user_variable_value(const ObString &var, common::ObObj &val) const
{
  int ret = OB_SUCCESS;
  ObSessionVariable sess_var;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
  } else if (OB_SUCCESS != user_var_val_map_.get_refactored(var, sess_var)) {
    ret = OB_ERR_USER_VARIABLE_UNKNOWN;
    LOG_WARN("unknown user variable", K(var), K(ret));
  } else {
    val = sess_var.value_;
  }
  return ret;
}

int ObBasicSessionInfo::get_user_variable_meta(const ObString &var, ObObjMeta &meta) const
{
  int ret = OB_SUCCESS;
  ObSessionVariable val;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
  } else if (OB_SUCCESS != user_var_val_map_.get_refactored(var, val)) {
    ret = OB_ERR_USER_VARIABLE_UNKNOWN;
    LOG_WARN("unknown user variable", K(var), K(ret));
  } else {
    meta = val.meta_;
  }
  return ret;
}

bool ObBasicSessionInfo::user_variable_exists(const ObString &var) const
{
  ObSessionVariable val;
  bool exist = false;
  int ret = OB_SUCCESS;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
  } else {
    exist = (OB_SUCCESS == user_var_val_map_.get_refactored(var, val));
  }
  return exist;
}

const ObSessionVariable *ObBasicSessionInfo::get_user_variable(const common::ObString &var) const
{
  const ObSessionVariable *sess_var = NULL;
  int ret = OB_SUCCESS;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
  } else {
    sess_var = user_var_val_map_.get(var);
  }
  return sess_var;
}

const common::ObObj *ObBasicSessionInfo::get_user_variable_value(const ObString &var) const
{
  const ObObj *val_obj = NULL;
  const ObSessionVariable *sess_var = NULL;
  int ret = OB_SUCCESS;
  if (var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid variable name", K(var), K(ret));
  } else if (NULL != (sess_var = user_var_val_map_.get(var))) {
    val_obj = &(sess_var->value_);
  } else {}//just return NULL
  return val_obj;
}

int ObBasicSessionInfo::get_session_label(uint64_t policy_id, ObLabelSeSessionLabel &session_label) const
{
  int ret = OB_ENTRY_NOT_EXIST;
  for (int64_t i = 0; ret != OB_SUCCESS && i < labels_.count(); ++i) {
    if (labels_[i].get_policy_id() == policy_id) {
      ret = OB_SUCCESS;
      session_label = labels_[i];
    }
  }
  return ret;
}

int ObBasicSessionInfo::replace_new_session_label(uint64_t policy_id, const ObLabelSeSessionLabel &new_session_label)
{
  int ret = OB_SUCCESS;
  ObArenaAllocator allocator;
  ObString serialized_data;
  bool found = false;
  for (int64_t i = 0; !found && i < labels_.count(); ++i) {
    if (labels_[i].get_policy_id() == policy_id) {
      found = true;
      labels_.at(i) = new_session_label;
    }
  }
  if (OB_SUCC(ret) && !found) {
    OZ (labels_.push_back(new_session_label));
  }
  OZ (ObLabelSeResolver::serialize_session_labels(labels_, allocator, serialized_data));
  OZ (update_sys_variable(SYS_VAR__OB_OLS_POLICY_SESSION_LABELS, serialized_data));
  return ret;
}

////////////////////////////////////////////////////////////////
int64_t ObBasicSessionInfo::to_string(char *buf, const int64_t buf_len) const
{
  int64_t pos = 0;
  J_OBJ_START();
  J_KV(KP(this), "id", sessid_,
       N_TENANT, get_tenant_name(), "tenant_id", tenant_id_,
       N_EFFECTIVE_TENANT, get_effective_tenant_name(), "effective_tenant_id", effective_tenant_id_,
       N_DATABASE, get_database_name(),
       N_USER, (lib::is_oracle_mode() ? get_user_name() : get_user_at_host()),
       "consistency_level", consistency_level_,
       "session_state", thread_data_.state_,
       "tx", OB_P(tx_desc_));
  J_OBJ_END();
  return pos;
}

int ObBasicSessionInfo::calc_need_serialize_vars(ObIArray<ObSysVarClassType> &sys_var_ids,
                                                 ObIArray<ObString> &user_var_names) const
{
  int ret = OB_SUCCESS;
  sys_var_ids.reset();
  user_var_names.reset();
  // 默认需要序列化的系统变量
  // 普通租户，序列化和 hardcode 不一致的变量
  const ObIArray<ObSysVarClassType> &ids = sys_var_inc_info_.get_all_sys_var_ids();
  for (int64_t i = 0; OB_SUCC(ret) && i < ids.count(); ++i) {
    int64_t sys_var_idx = -1;
    if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(ids.at(i), sys_var_idx))) {
      LOG_WARN("fail to calc sys var store idx", K(i), K(sys_var_idx), K(ids.at(i)), K(ret));
    } else if ((ObSysVariables::get_flags(sys_var_idx) &
                (ObSysVarFlag::SESSION_SCOPE | // "delta compare algorithm"
                 ObSysVarFlag::NEED_SERIALIZE |
                 ObSysVarFlag::QUERY_SENSITIVE))) {
      if (OB_FAIL(sys_var_ids.push_back(ids.at(i)))) {
        LOG_WARN("fail to push back sys var id", K(i), K(ids.at(i)), K(sys_var_ids), K(ret));
      }
    }
  }

  if (OB_SUCC(ret) && cur_phy_plan_ != nullptr) {
    // 处理该语句用到的需要序列化的用户变量和系统变量
    const ObIArray<ObVarInfo> &extra_serialize_vars = cur_phy_plan_->get_vars();
    for (int64_t i = 0; OB_SUCC(ret) && i < extra_serialize_vars.count(); ++i) {
      const ObVarInfo &var_info = extra_serialize_vars.at(i);
      if (USER_VAR == var_info.type_) {
        // 用户变量
        if (OB_FAIL(user_var_names.push_back(var_info.name_))) {
          LOG_WARN("fail to push user var name", K(var_info), K(user_var_names), K(ret));
        }
      } else if (SYS_VAR == var_info.type_) {
        // 系统变量
        ObSysVarClassType sys_var_id = ObSysVarFactory::find_sys_var_id_by_name(var_info.name_);
        if (SYS_VAR_INVALID == sys_var_id) {
          ret = OB_ERR_UNEXPECTED;
          LOG_WARN("invalid sys var id", K(sys_var_id), K(var_info), K(ret));
        } else {
          // 去重
          bool sys_var_exist = false;
          for (int64_t j = 0; OB_SUCC(ret) && !sys_var_exist && j < sys_var_ids.count(); ++j) {
            if (sys_var_id == sys_var_ids.at(j)) {
              sys_var_exist = true;
            }
          }
          if (OB_SUCCESS == ret && !sys_var_exist) {
            if (OB_FAIL(sys_var_ids.push_back(sys_var_id))) {
              LOG_WARN("fail to push back sys var id", K(sys_var_id), K(var_info), K(sys_var_ids),
                       K(ret));
            }
          }
        }
      } else {
        ret = OB_ERR_UNEXPECTED;
        LOG_ERROR("invalid var info type", K(var_info.type_), K(var_info), K(ret));
      }
    }
  }
  return ret;
}

OB_SERIALIZE_MEMBER(ObBasicSessionInfo::TableStmtType, table_id_, stmt_type_);

OB_DEF_SERIALIZE(ObBasicSessionInfo::SysVarsCacheData)
{
  int ret = OB_SUCCESS;
  LST_DO_CODE(OB_UNIS_ENCODE,
              autocommit_,
              ob_enable_trace_log_,
              ob_org_cluster_id_,
              ob_query_timeout_,
              ob_trx_timeout_,
              collation_connection_,
              sql_mode_,
              ob_trx_idle_timeout_,
              nls_collation_,
              nls_nation_collation_,
              ob_enable_sql_audit_,
              nls_length_semantics_,
              nls_formats_[NLS_DATE],
              nls_formats_[NLS_TIMESTAMP],
              nls_formats_[NLS_TIMESTAMP_TZ],
              ob_trx_lock_timeout_,
              ob_trace_info_,
              ob_plsql_ccflags_);
  return ret;
}

OB_DEF_DESERIALIZE(ObBasicSessionInfo::SysVarsCacheData)
{
  int ret = OB_SUCCESS;
  LST_DO_CODE(OB_UNIS_DECODE,
              autocommit_,
              ob_enable_trace_log_,
              ob_org_cluster_id_,
              ob_query_timeout_,
              ob_trx_timeout_,
              collation_connection_,
              sql_mode_,
              ob_trx_idle_timeout_,
              nls_collation_,
              nls_nation_collation_,
              ob_enable_sql_audit_,
              nls_length_semantics_,
              nls_formats_[NLS_DATE],
              nls_formats_[NLS_TIMESTAMP],
              nls_formats_[NLS_TIMESTAMP_TZ],
              ob_trx_lock_timeout_,
              ob_trace_info_,
              ob_plsql_ccflags_);
  set_nls_date_format(nls_formats_[NLS_DATE]);
  set_nls_timestamp_format(nls_formats_[NLS_TIMESTAMP]);
  set_nls_timestamp_tz_format(nls_formats_[NLS_TIMESTAMP_TZ]);
  set_ob_trace_info(ob_trace_info_);
  set_plsql_ccflags(ob_plsql_ccflags_);
  return ret;
}

OB_DEF_SERIALIZE_SIZE(ObBasicSessionInfo::SysVarsCacheData)
{
  int64_t len = 0;
  LST_DO_CODE(OB_UNIS_ADD_LEN,
              autocommit_,
              ob_enable_trace_log_,
              ob_org_cluster_id_,
              ob_query_timeout_,
              ob_trx_timeout_,
              collation_connection_,
              sql_mode_,
              ob_trx_idle_timeout_,
              nls_collation_,
              nls_nation_collation_,
              ob_enable_sql_audit_,
              nls_length_semantics_,
              nls_formats_[NLS_DATE],
              nls_formats_[NLS_TIMESTAMP],
              nls_formats_[NLS_TIMESTAMP_TZ],
              ob_trx_lock_timeout_,
              ob_trace_info_,
              ob_plsql_ccflags_);
  return len;
}

OB_DEF_SERIALIZE(ObBasicSessionInfo)
{
  int ret = OB_SUCCESS;
  ObTimeZoneInfo tmp_tz_info;//为了兼容老版本，创建临时time zone info 占位
  // To be compatible with old version which store sql_mode and compatibility mode in ObSQLModeManager;
  int64_t compatibility_mode_index = 0;
  if (OB_FAIL(compatibility_mode2index(get_compatibility_mode(), compatibility_mode_index))) {
    LOG_WARN("convert compatibility mode to index failed", K(ret));
  }
  bool has_tx_desc = tx_desc_ != NULL;
  OB_UNIS_ENCODE(has_tx_desc);
  if (has_tx_desc) {
    OB_UNIS_ENCODE(*tx_desc_);
    LOG_TRACE("serialize txDesc", KPC_(tx_desc));
  }
  LST_DO_CODE(OB_UNIS_ENCODE,
              consistency_level_,
              compatibility_mode_index,
              tmp_tz_info,
              // NOTE: rpc_tenant_id may cause compatability problem,
              // But only in diagnose tenant, so keep the stupid hack as it is.
              tenant_id_ | (rpc_tenant_id_ << 32),
              effective_tenant_id_,
              is_changed_to_temp_tenant_,
              user_id_,
              is_master_session() ? sessid_ : master_sessid_,
              capability_.capability_,
              thread_data_.database_name_);
  // 序列化需要序列化的用户变量和系统变量
  ObSEArray<ObSysVarClassType, 64> sys_var_ids;
  ObSEArray<ObString, 32> user_var_names;
  if (OB_FAIL(ret)) {
  } else if (OB_FAIL(calc_need_serialize_vars(sys_var_ids, user_var_names))) {
    LOG_WARN("fail to calc need serialize vars", K(ret));
  } else {
    ObSEArray<std::pair<ObString, ObSessionVariable>, 32> actual_ser_user_vars;
    ObSessionVariable user_var_val;
    for (int64_t i = 0; OB_SUCC(ret) && i < user_var_names.count(); ++i) {
      user_var_val.reset();
      const ObString &user_var_name = user_var_names.at(i);
      ret = user_var_val_map_.get_refactored(user_var_name, user_var_val);
      if (OB_SUCCESS != ret && OB_HASH_NOT_EXIST != ret) {
        LOG_WARN("fail to get user var from session user var map", K(i), K(user_var_name),
                 K(user_var_val_map_.size()), K(ret));
      } else {
        if (OB_SUCCESS == ret
            && OB_FAIL(actual_ser_user_vars.push_back(std::make_pair(user_var_name, user_var_val)))) {
          LOG_WARN("fail to push back pair(user_var_name, user_var_val)", K(buf_len),
                   K(pos), K(user_var_name), K(user_var_val), K(ret));
        } else {
          ret = OB_SUCCESS;
        }
      }
    }

    if (OB_SUCC(ret)) {
      if (OB_FAIL(serialization::encode(buf, buf_len, pos, actual_ser_user_vars.count()))) {
        LOG_WARN("fail to serialize user var count", K(ret), K(buf_len), K(pos),
                 K(actual_ser_user_vars.count()));
      } else {
        for (int64_t i = 0; OB_SUCC(ret) && i < actual_ser_user_vars.count(); ++i) {
          const ObString &user_var_name = actual_ser_user_vars.at(i).first;
          const ObSessionVariable &user_var_val = actual_ser_user_vars.at(i).second;
          if (OB_FAIL(serialization::encode(buf, buf_len, pos, user_var_name))) {
            LOG_WARN("fail to serialize user var name", K(buf_len), K(pos), K(user_var_name),
                     K(ret));
          } else if (OB_FAIL(serialization::encode(buf, buf_len, pos, user_var_val.meta_))) {
            LOG_WARN("fail to serialize user var val meta", K(buf_len), K(pos),
                     K(user_var_val.meta_), K(ret));
          } else if (OB_FAIL(serialization::encode(buf, buf_len, pos, user_var_val.value_))) {
            LOG_WARN("fail to serialize user var val value", K(buf_len), K(pos),
                     K(user_var_val.value_), K(ret));
          } else {}
        }
      }
    }
  }

  // split function, make stack checker happy
  [&](){
  if (OB_SUCC(ret)) {
    if (OB_FAIL(serialization::encode(buf, buf_len, pos, sys_var_ids.count()))) {
      LOG_WARN("fail to serialize sys var count", K(buf_len), K(pos), K(sys_var_ids.count()), K(ret));
    }
    for (int64_t i = 0; OB_SUCC(ret) && i < sys_var_ids.count(); ++i) {
      int64_t sys_var_idx = -1;
      if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(sys_var_ids.at(i), sys_var_idx))) {
        LOG_WARN("fail to calc sys var store idx", K(i), K(sys_var_idx), K(sys_var_ids.at(i)), K(ret));
      } else if (sys_var_idx < 0 || get_sys_var_count() <= sys_var_idx) {
        ret = OB_ERR_UNEXPECTED;
        LOG_ERROR("sys var idx is invalid", K(sys_var_idx), K(get_sys_var_count()), K(ret));
      } else if (OB_ISNULL(sys_vars_[sys_var_idx])) {
        ret = OB_ERR_UNEXPECTED;
        LOG_ERROR("sys var is NULL", K(ret), K(sys_var_idx), K(get_sys_var_count()));
      } else {
        int16_t sys_var_id = static_cast<int16_t>(sys_vars_[sys_var_idx]->get_type());
        if (OB_FAIL(serialization::encode(buf, buf_len, pos, sys_var_id))) {
          LOG_ERROR("fail to serialize sys var id", K(buf_len), K(pos), K(sys_var_id), K(ret));
        } else if (OB_FAIL(sys_vars_[sys_var_idx]->serialize(buf, buf_len, pos))) {
          LOG_ERROR("fail to serialize sys var", K(buf_len), K(pos), K(i), K(sys_var_idx),
                    K(*sys_vars_[sys_var_idx]), K(ret));
        } else {
          LOG_DEBUG("serialize sys vars", K(sys_var_idx),
                    "name", ObSysVariables::get_name(sys_var_idx),
                    "val", sys_vars_[sys_var_idx]->get_value(),
                    "def", ObSysVariables::get_default_value(sys_var_idx));
        }
      }
    }
  }

  if (OB_FAIL(ret)) {
    LOG_WARN("fail to encode session info", K(ret));
  } else {
    bool tx_read_only = get_tx_read_only();
    if (OB_FAIL(serialization::encode_bool(buf, buf_len, pos, tx_read_only))) {
      LOG_WARN("fail to encode tx_read_only", K(ret));
    }
  }

  // 不再有意义字段，为了兼容性考虑
  bool unused_literal_query = false;
  int64_t unused_inner_safe_weak_read_snapshot = 0;
  int64_t unused_weak_read_snapshot_source = 0;
  int64_t unused_safe_weak_read_snapshot = 0;

  bool need_serial_exec = trans_flags_.need_serial_exec();
  uint64_t sql_scope_flags = sql_scope_flags_.get_flags();
  LST_DO_CODE(OB_UNIS_ENCODE,
              sys_vars_cache_.inc_data_,
              unused_safe_weak_read_snapshot,
              unused_inner_safe_weak_read_snapshot,
              unused_literal_query,
              tz_info_wrap_,
              app_trace_id_,
              proxy_capability_.capability_,
              client_mode_,
              proxy_sessid_,
              nested_count_,
              thread_data_.user_name_,
              next_tx_isolation_,
              read_snapshot_version_,
              check_sys_variable_,
              unused_weak_read_snapshot_source,
              database_id_,
              thread_data_.user_at_host_name_,
              thread_data_.user_at_client_ip_,
              current_execution_id_,
              labels_,
              total_stmt_tables_,
              cur_stmt_tables_,
              is_foreign_key_cascade_,
              sys_var_in_pc_str_,
              config_in_pc_str_,
              is_foreign_key_check_exist_,
              need_serial_exec,
              sql_scope_flags,
              stmt_type_,
              thread_data_.client_addr_,
              thread_data_.user_client_addr_,
              process_query_time_);
  }();
  return ret;
}

OB_DEF_DESERIALIZE(ObBasicSessionInfo)
{
  int ret = OB_SUCCESS;
  ObTimeZoneInfo tmp_tz_info;//为了兼容老版本，创建临时time zone info 占位
  int64_t compatibility_mode_index = 0;
  is_deserialized_ = true;
  bool has_tx_desc = 0;
  if (OB_FAIL(serialization::decode(buf, data_len, pos, has_tx_desc))) {
    LOG_WARN("fail to deserialize has_tx_desc_", K(data_len), K(pos), K(ret));
  } else if (has_tx_desc) {
    auto txs = MTL(transaction::ObTransService*);
    if (OB_FAIL(txs->acquire_tx(buf, data_len, pos, tx_desc_))) {
      LOG_WARN("acquire tx by deserialize fail", K(data_len), K(pos), K(ret));
    } else {
      LOG_TRACE("deserialize txDesc from session", KPC_(tx_desc));
    }
  } else {
    tx_desc_ = NULL;
  }
  LST_DO_CODE(OB_UNIS_DECODE,
              consistency_level_,
              compatibility_mode_index,
              tmp_tz_info,
              tenant_id_,
              effective_tenant_id_,
              is_changed_to_temp_tenant_,
              user_id_,
              master_sessid_,
              capability_.capability_,
              thread_data_.database_name_);
  rpc_tenant_id_ = (tenant_id_ >> 32);
  tenant_id_ = (tenant_id_ << 32 >> 32);
  // 反序列化需要序列化的用户变量和系统变量
  int64_t deserialize_user_var_count = 0;
  int64_t deserialize_sys_var_count = 0;

  if (OB_FAIL(ret)) {
  } else if (OB_FAIL(serialization::decode(buf, data_len, pos, deserialize_user_var_count))) {
    LOG_WARN("fail to deserialize user var count", K(data_len), K(pos), K(ret));
  } else {
    ObSessionVariable user_var_val;
    for (int64_t i = 0; OB_SUCC(ret) && i < deserialize_user_var_count; ++i) {
      ObString user_var_name;
      user_var_val.reset();
      if (OB_FAIL(serialization::decode(buf, data_len, pos, user_var_name))) {
        LOG_WARN("fail to deserialize user var name", K(i), K(data_len), K(pos), K(ret));
      } else if (OB_FAIL(name_pool_.write_string(user_var_name, &user_var_name))) {
        LOG_WARN("fail to write user_var_name to string_buf_", K(user_var_name), K(ret));
      } else if (OB_FAIL(serialization::decode(buf, data_len, pos, user_var_val.meta_))) {
        LOG_WARN("fail to deserialize user var val meta", K(i), K(data_len), K(pos), K(ret));
      } else if (OB_FAIL(serialization::decode(buf, data_len, pos, user_var_val.value_))) {
        LOG_WARN("fail to deserialize user var val value", K(i), K(data_len), K(pos), K(ret));
      } else {
        if (OB_FAIL(user_var_val_map_.set_refactored(user_var_name, user_var_val))) {
          LOG_WARN("Insert value into map failed", K(user_var_name), K(user_var_val), K(ret));
        } else {
          ret = OB_SUCCESS;
        }
      }
    }
  }

  sys_var_inc_info_.reset();
  // 当 sys_var_base_version_ == CACHED_SYS_VAR_VERSION 时说明有缓存，不需要 load 默认值
  // 否则说明没有缓存，需要 load 默认值，然后打补丁
  if (CACHED_SYS_VAR_VERSION != sys_var_base_version_) {
    OZ (load_all_sys_vars_default());
  } else {
    // cached already, skip load default vars
    OZ (process_session_variable_fast());
  }

  if (OB_SUCC(ret)) {
    ObTZMapWrap tz_map_wrap;
    if (OB_FAIL(OTTZ_MGR.get_tenant_tz(tenant_id_, tz_map_wrap))) {
      LOG_WARN("get tenant timezone map failed", K(ret));
    } else {
      tz_info_wrap_.set_tz_info_map(tz_map_wrap.get_tz_map());
    }
  }
  if (OB_SUCC(ret)) {
    if (OB_FAIL(serialization::decode(buf, data_len, pos, deserialize_sys_var_count))) {
      LOG_WARN("fail to deserialize sys var count", K(data_len), K(pos), K(ret));
    } else {
      LOG_DEBUG("total des sys vars", K(deserialize_sys_var_count));
      const bool check_timezone_valid = false;
      for (int64_t i = 0; OB_SUCC(ret) && i < deserialize_sys_var_count; ++i) {
        ObObj tmp_val;
        ObBasicSysVar *sys_var = NULL;
        ObSysVarClassType sys_var_id = SYS_VAR_INVALID;
        int16_t tmp_sys_var_id = -1;
        int64_t store_idx = -1;
        if (OB_FAIL(serialization::decode(buf, data_len, pos, tmp_sys_var_id))) {
          LOG_WARN("fail to deserialize sys var id", K(data_len), K(pos), K(ret));
        } else if (FALSE_IT(sys_var_id = static_cast<ObSysVarClassType>(tmp_sys_var_id))) {
        } else if (OB_FAIL(sys_var_inc_info_.add_sys_var_id(sys_var_id))) {
          LOG_WARN("fail to add sys var id", K(sys_var_id), K(ret));
        } else if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(sys_var_id, store_idx))) {
          if (OB_SYS_VARS_MAYBE_DIFF_VERSION == ret) {
            // 可能是版本不同，为了兼容，跳过这段数据，并继续循环
            ret = OB_SUCCESS;
            int64_t sys_var_version = 0;
            int64_t sys_var_len = 0;
            OB_UNIS_DECODEx(sys_var_version);
            OB_UNIS_DECODEx(sys_var_len);
            if (OB_SUCC(ret)) {
              pos += sys_var_len; // 跳过这段数据
              LOG_WARN("invalid sys var id, maybe version is different, skip it", K(sys_var_id));
            }
          } else {
            LOG_ERROR("invalid sys var id", K(sys_var_id), K(ret));
          }
        } else if (OB_FAIL(create_sys_var(sys_var_id, store_idx, sys_var))) {
          LOG_WARN("fail to create sys var", K(sys_var_id), K(ret));
        } else if (OB_ISNULL(sys_var)) {
          ret = OB_ERR_UNEXPECTED;
          LOG_WARN("create sys var is NULL", K(ret));
        } else if (OB_FAIL(sys_var->deserialize(buf, data_len, pos))) {
          LOG_WARN("fail to deserialize sys var", K(data_len), K(pos), K(sys_var_id), K(ret));
        } else if (OB_FAIL(deep_copy_sys_variable(*sys_var, sys_var_id, sys_var->get_value()))) {
          LOG_WARN("fail to update system variable", K(sys_var_id), K(sys_var->get_value()), K(ret));
        } else if (OB_FAIL(process_session_variable(sys_var_id, sys_var->get_value(),
                                                    check_timezone_valid,
                                                    false /*is_update_sys_var*/))) {
          LOG_WARN("process system variable error",  K(ret), K(*sys_var));
        }
      }
    }

    if (OB_SUCC(ret)) {
      bool tx_read_only = false;
      if (OB_FAIL(serialization::decode_bool(buf, data_len, pos, &tx_read_only))) {
        LOG_WARN("fail to decode tx_read_only", K(ret));
      } else {
        // direct assignment because in this case we won't track trans_specified_status
        next_tx_read_only_ = tx_read_only;
      }
    }
  }

  // split function, make stack checker happy
  [&]() {
  int64_t unused_inner_safe_weak_read_snapshot = 0;
  int64_t unused_weak_read_snapshot_source = 0;
  int64_t unused_safe_weak_read_snapshot = 0;
  bool unused_literal_query = false;
  bool need_serial_exec = false;
  uint64_t sql_scope_flags = 0;

  sys_var_in_pc_str_.reset(); //sys_var_in_pc_str_在反序列化系统变量阶段可能会被污染，需要reset掉
  config_in_pc_str_.reset();
  const ObTZInfoMap *tz_info_map = tz_info_wrap_.get_tz_info_offset().get_tz_info_map();
  LST_DO_CODE(OB_UNIS_DECODE,
              sys_vars_cache_.inc_data_,
              unused_safe_weak_read_snapshot,
              unused_inner_safe_weak_read_snapshot,
              unused_literal_query,
              tz_info_wrap_,
              app_trace_id_,
              proxy_capability_.capability_,
              client_mode_,
              proxy_sessid_,
              nested_count_,
              thread_data_.user_name_,
              next_tx_isolation_,
              read_snapshot_version_,
              check_sys_variable_,
              unused_weak_read_snapshot_source,
              database_id_,
              thread_data_.user_at_host_name_,
              thread_data_.user_at_client_ip_,
              current_execution_id_,
              labels_,
              total_stmt_tables_,
              cur_stmt_tables_,
              is_foreign_key_cascade_,
              sys_var_in_pc_str_,
              config_in_pc_str_,
              is_foreign_key_check_exist_,
              need_serial_exec,
              sql_scope_flags,
              stmt_type_,
              thread_data_.client_addr_,
              thread_data_.user_client_addr_,
              process_query_time_);
  // deep copy string.
  if (OB_SUCC(ret)) {
    if (OB_FAIL(name_pool_.write_string(app_trace_id_, &app_trace_id_))) {
      LOG_WARN("fail to write app_trace_id to string_buf_", K(app_trace_id_), K(ret));
    } else if (OB_FAIL(name_pool_.write_string(thread_data_.user_name_,
                                              &thread_data_.user_name_))) {
      LOG_WARN("fail to write username to string_buf_", K(thread_data_.user_name_), K(ret));
    } else if (OB_FAIL(name_pool_.write_string(thread_data_.user_at_host_name_,
                                              &thread_data_.user_at_host_name_))) {
      LOG_WARN("fail to write user_at_host_name to string_buf_",
                K(thread_data_.user_at_host_name_), K(ret));
    } else if (OB_FAIL(name_pool_.write_string(thread_data_.user_at_client_ip_,
                                              &thread_data_.user_at_client_ip_))) {
      LOG_WARN("fail to write user_at_client_ip to string_buf_",
                K(thread_data_.user_at_client_ip_), K(ret));
    } else if (OB_FAIL(name_pool_.write_string(sys_var_in_pc_str_, &sys_var_in_pc_str_))) {
      LOG_WARN("fail to write sys_var_in_pc_str to string_buf_", K(sys_var_in_pc_str_), K(ret));
    } else if (OB_FAIL(name_pool_.write_string(config_in_pc_str_, &config_in_pc_str_))) {
      LOG_WARN("fail to write config_in_pc_str_ to string_buf_", K(config_in_pc_str_), K(ret));
    }
  }
  trans_flags_.set_need_serial_exec(need_serial_exec);
  sql_scope_flags_.set_flags(sql_scope_flags);
  is_deserialized_ = true;
  tz_info_wrap_.set_tz_info_map(tz_info_map);

  //在升级过程中,由于版本差异,高版本server如果收到低版本server发来的session变量,需要兼容处理
  //反序列化完成后, 由于后面存在再次序列化给其他server的场景, 所以需要补齐需要序列化的系统变量
  //fix以下场景   A(2.1)->B(2.2)->C(2.2)-> ret = -4016
  if (OB_SUCC(ret) && GET_MIN_CLUSTER_VERSION() < CLUSTER_CURRENT_VERSION) {
    ObArenaAllocator calc_buf(ObModIds::OB_SQL_SESSION);
    for (int64_t i = 0; OB_SUCC(ret) && i < get_sys_var_count(); ++i) {
      if ((ObSysVariables::get_flags(i) & ObSysVarFlag::NEED_SERIALIZE)
          && OB_ISNULL(sys_vars_[i])) {
        if (OB_FAIL(load_default_sys_variable(calc_buf, i))) {
          LOG_WARN("fail to load default sys variable", K(ret), K(i));
        }
      }
    }
  }
  release_to_pool_ = OB_SUCC(ret);
  }();
  return ret;
}

OB_DEF_SERIALIZE(ObBasicSessionInfo::SysVarIncInfo)
{
  int ret = OB_SUCCESS;
  OB_UNIS_ENCODE(all_sys_var_ids_);
  return ret;
}

OB_DEF_DESERIALIZE(ObBasicSessionInfo::SysVarIncInfo)
{
  int ret = OB_SUCCESS;
  OB_UNIS_DECODE(all_sys_var_ids_);
  return ret;
}

OB_DEF_SERIALIZE_SIZE(ObBasicSessionInfo::SysVarIncInfo)
{
  int64_t len = 0;
  OB_UNIS_ADD_LEN(all_sys_var_ids_);
  return len;
}

ObBasicSessionInfo::SysVarIncInfo::SysVarIncInfo()
  : all_sys_var_ids_()
{}

ObBasicSessionInfo::SysVarIncInfo::~SysVarIncInfo()
{}

int ObBasicSessionInfo::SysVarIncInfo::add_sys_var_id(ObSysVarClassType sys_var_id)
{
  int ret = OB_SUCCESS;
  OZ (add_var_to_array_no_dup(all_sys_var_ids_, sys_var_id), all_sys_var_ids_, sys_var_id);
  return ret;
}

int ObBasicSessionInfo::SysVarIncInfo::get_des_sys_var_id(int64_t idx,
                                                          ObSysVarClassType &sys_var_id) const
{
  int ret = OB_SUCCESS;
  OV (0 <= idx && idx < all_sys_var_ids_.count());
  OX (sys_var_id = all_sys_var_ids_.at(idx));
  return ret;
}

bool ObBasicSessionInfo::SysVarIncInfo::all_has_sys_var_id(ObSysVarClassType sys_var_id) const
{
  return has_exist_in_array(all_sys_var_ids_, sys_var_id);
}

int64_t ObBasicSessionInfo::SysVarIncInfo::all_count() const
{
  return all_sys_var_ids_.count();
}

const ObBasicSessionInfo::SysVarIds &ObBasicSessionInfo::SysVarIncInfo::get_all_sys_var_ids() const
{
  return all_sys_var_ids_;
}

int ObBasicSessionInfo::SysVarIncInfo::assign(const SysVarIncInfo &other)
{
  int ret = OB_SUCCESS;
  if (this != &other) {
    OZ (all_sys_var_ids_.assign(other.all_sys_var_ids_));
  }
  return ret;
}

int ObBasicSessionInfo::SysVarIncInfo::reset()
{
  int ret = OB_SUCCESS;
  OX (all_sys_var_ids_.reset());
  return ret;
}

int ObBasicSessionInfo::load_all_sys_vars_default()
{
  int ret = OB_SUCCESS;
  OZ (clean_all_sys_vars());
  OZ (load_default_sys_variable(false, false));
  return ret;
}

int ObBasicSessionInfo::clean_all_sys_vars()
{
  int ret = OB_SUCCESS;
  for (int64_t i = 0; OB_SUCC(ret) && i < get_sys_var_count(); ++i) {
    if (OB_NOT_NULL(sys_vars_[i])) {
      OX (sys_vars_[i]->clean_value());
    }
  }
  OX (base_sys_var_alloc_.reset());
  OX (inc_sys_var_alloc_.reset());
  return ret;
}

int ObBasicSessionInfo::load_all_sys_vars(ObSchemaGetterGuard &schema_guard)
{
  int ret = OB_SUCCESS;
  const ObSysVariableSchema *sys_var_schema = NULL;
  OZ (sys_var_fac_.create_all_sys_vars());
  OZ (schema_guard.get_sys_variable_schema(effective_tenant_id_, sys_var_schema));
  OV (OB_NOT_NULL(sys_var_schema));
  OZ (load_all_sys_vars(*sys_var_schema, true));
  return ret;
}

int ObBasicSessionInfo::load_all_sys_vars(const ObSysVariableSchema &sys_var_schema, bool sys_var_created)
{
  int ret = OB_SUCCESS;
  OZ (clean_all_sys_vars());
  if (!sys_var_created) {
    OZ (sys_var_fac_.create_all_sys_vars());
  }
  OX (influence_plan_var_indexs_.reset());
  ObArenaAllocator calc_buf(ObModIds::OB_SQL_SESSION);
  for (int64_t i = 0; OB_SUCC(ret) && i < get_sys_var_count(); i++) {
    ObSysVarClassType sys_var_id = ObSysVariables::get_sys_var_id(i);
    const ObSysVarSchema *sys_var = NULL;
    OZ (sys_var_schema.get_sysvar_schema(sys_var_id, sys_var), sys_var_id, i);
    OV (OB_NOT_NULL(sys_var));
    OZ (load_sys_variable(calc_buf, sys_var->get_name(), sys_var->get_data_type(),
                          sys_var->get_value(), sys_var->get_min_val(),
                          sys_var->get_max_val(), sys_var->get_flags(), true));
    if (OB_NOT_NULL(sys_vars_[i]) && OB_SUCC(ret)) {
      if (sys_vars_[i]->is_influence_plan()) {
        OZ (influence_plan_var_indexs_.push_back(i));
      }
      if (ObSysVariables::get_default_value(i) != sys_vars_[i]->get_value()) {
        OZ (sys_var_inc_info_.add_sys_var_id(sys_var_id));
        LOG_DEBUG("schema and def not identical", K(sys_var_id), "val", sys_vars_[i]->get_value(),
                  "def", ObSysVariables::get_default_value(i));
      }
    }
  }
  release_to_pool_ = OB_SUCC(ret);
  if (!is_deserialized_) {
    OZ (gen_sys_var_in_pc_str());
    OZ (gen_configs_in_pc_str());
  }
  return ret;
}

OB_DEF_SERIALIZE_SIZE(ObBasicSessionInfo)
{
  int64_t len = 0;
  ObTimeZoneInfo tmp_tz_info;//为了兼容老版本，创建临时time zone info 占位
  int ret = OB_SUCCESS;
  // To be compatible with old version which store sql_mode and compatibility mode in ObSQLModeManager;
  int64_t compatibility_mode_index = 0;
  if (OB_FAIL(compatibility_mode2index(get_compatibility_mode(), compatibility_mode_index))) {
    LOG_WARN("convert compatibility mode to index failed", K(ret));
  }
  char has_tx_desc = tx_desc_ != NULL ? 1 : 0;
  OB_UNIS_ADD_LEN(has_tx_desc);
  if (has_tx_desc) {
    OB_UNIS_ADD_LEN(*tx_desc_);
  }
  LST_DO_CODE(OB_UNIS_ADD_LEN,
              consistency_level_,
              compatibility_mode_index,
              tmp_tz_info,
              tenant_id_ | (rpc_tenant_id_<<32),
              effective_tenant_id_,
              is_changed_to_temp_tenant_,
              user_id_,
              is_master_session() ? sessid_ : master_sessid_,
              capability_.capability_,
              thread_data_.database_name_);

  // 计算需要序列化的用户变量和系统变量的序列化长度
  ObSEArray<ObSysVarClassType, 128> sys_var_ids;
  ObSEArray<ObString, 32> user_var_names;
  if (OB_FAIL(ret)) {
  } else if (OB_FAIL(calc_need_serialize_vars(sys_var_ids, user_var_names))) {
    LOG_WARN("fail to calc need serialize vars", K(ret));
  } else {
    int64_t actual_ser_user_var_count = 0;
    ObSessionVariable user_var_val;
    for (int64_t i = 0; OB_SUCC(ret) && i < user_var_names.count(); ++i) {
      user_var_val.reset();
      const ObString &user_var_name = user_var_names.at(i);
      ret = user_var_val_map_.get_refactored(user_var_name, user_var_val);
      if (OB_SUCCESS != ret && OB_HASH_NOT_EXIST != ret) {
        LOG_WARN("fail to get user var from session user var map", K(i), K(user_var_name),
                 K(user_var_val_map_.size()), K(ret));
      } else {
        if (OB_SUCCESS == ret) {
          actual_ser_user_var_count++;
          len += serialization::encoded_length(user_var_name);
          len += serialization::encoded_length(user_var_val.meta_);
          len += serialization::encoded_length(user_var_val.value_);
        }
        ret = OB_SUCCESS;
      }
    }
    len += serialization::encoded_length(actual_ser_user_var_count);
  }
  if (OB_SUCC(ret)) {
    len += serialization::encoded_length(sys_var_ids.count());
    for (int64_t i = 0; OB_SUCC(ret) && i < sys_var_ids.count(); ++i) {
      int64_t sys_var_idx = -1;
      ObSysVarClassType &type = sys_var_ids.at(i);
      if (OB_FAIL(ObSysVarFactory::calc_sys_var_store_idx(type, sys_var_idx))) {
        LOG_WARN("fail to calc sys var store idx", K(i), K(sys_var_idx), K(type), K(ret));
      } else if (sys_var_idx < 0 || get_sys_var_count() <= sys_var_idx) {
        ret = OB_ERR_UNEXPECTED;
        LOG_ERROR("sys var idx is invalid", K(sys_var_idx), K(get_sys_var_count()), K(ret));
      } else if (OB_ISNULL(sys_vars_[sys_var_idx])) {
        ret = OB_ERR_UNEXPECTED;
        LOG_ERROR("sys var is NULL", K(ret), K(sys_var_idx), K(get_sys_var_count()));
      } else {
        int16_t sys_var_id = static_cast<int16_t>(sys_vars_[sys_var_idx]->get_type());
        len += serialization::encoded_length(sys_var_id);
        len += sys_vars_[sys_var_idx]->get_serialize_size();
      }
    }
  }
  if (OB_SUCC(ret)) {
    bool tx_read_only = get_tx_read_only();
    len += serialization::encoded_length_bool(tx_read_only);
  }
  bool unused_literal_query = false;
  int64_t unused_inner_safe_weak_read_snapshot = 0;
  int64_t unused_weak_read_snapshot_source = 0;
  int64_t unused_safe_weak_read_snapshot = 0;
  bool need_serial_exec = trans_flags_.need_serial_exec();
  uint64_t sql_scope_flags = sql_scope_flags_.get_flags();

  LST_DO_CODE(OB_UNIS_ADD_LEN,
              sys_vars_cache_.inc_data_,
              unused_safe_weak_read_snapshot,
              unused_inner_safe_weak_read_snapshot,
              unused_literal_query,
              tz_info_wrap_,
              app_trace_id_,
              proxy_capability_.capability_,
              client_mode_,
              proxy_sessid_,
              nested_count_,
              thread_data_.user_name_,
              next_tx_isolation_,
              read_snapshot_version_,
              check_sys_variable_,
              unused_weak_read_snapshot_source,
              database_id_,
              thread_data_.user_at_host_name_,
              thread_data_.user_at_client_ip_,
              current_execution_id_,
              labels_,
              total_stmt_tables_,
              cur_stmt_tables_,
              is_foreign_key_cascade_,
              sys_var_in_pc_str_,
              config_in_pc_str_,
              is_foreign_key_check_exist_,
              need_serial_exec,
              sql_scope_flags,
              stmt_type_,
              thread_data_.client_addr_,
              thread_data_.user_client_addr_,
              process_query_time_);
  return len;
}

////////////////////////////////////////////////////////////////
void ObBasicSessionInfo::reset_session_changed_info()
{
  changed_sys_vars_.reset();
  changed_user_vars_.reset();
  is_database_changed_ = false;
  changed_var_pool_.reset();
  feedback_manager_.reset();
}

bool ObBasicSessionInfo::is_already_tracked(const ObSysVarClassType &sys_var_id,
                                            const ObIArray<ChangedVar> &array) const
{
  bool found = false;
  for (int64_t i = 0; !found && i < array.count(); ++i) {
    if (array.at(i).id_ == sys_var_id) {
      found = true;
      break;
    }
  }
  return found;
}

bool ObBasicSessionInfo::is_already_tracked(const ObString& name,
                                            const ObIArray<ObString> &array) const
{
  bool found = false;
  for (int64_t i = 0; !found && i < array.count(); ++i) {
    if (array.at(i) == name) {
      found = true;
      break;
    }
  }
  return found;
}

int ObBasicSessionInfo::add_changed_sys_var(const ObSysVarClassType &sys_var_id,
                                            const ObObj &old_val,
                                            ObIArray<ChangedVar> &array)
{
  int ret = OB_SUCCESS;
  ObObj val;
  if (SYS_VAR_INVALID == sys_var_id) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid input value", K(sys_var_id), K(old_val), K(ret));
  } else if (OB_FAIL(deep_copy_obj(changed_var_pool_, old_val, val))) {
    LOG_WARN("failed to deep copy system var old value", K(ret), K(old_val));
  } else if (OB_FAIL(array.push_back(ChangedVar(sys_var_id, val)))) {
    LOG_WARN("fail to push back", K(sys_var_id), K(old_val), K(ret));
  }
  return ret;
}

int ObBasicSessionInfo::add_changed_user_var(const ObString &name,
                                             common::ObIArray<common::ObString> &array)
{
  return array.push_back(name);
}

int ObBasicSessionInfo::track_sys_var(const ObSysVarClassType &sys_var_id,
                                      const ObObj& old_val)
{
  int ret = OB_SUCCESS;
  if (SYS_VAR_INVALID == sys_var_id) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid input value", K(sys_var_id), K(ret));
  } else if (!is_already_tracked(sys_var_id, changed_sys_vars_)) {
    if (OB_FAIL(add_changed_sys_var(sys_var_id, old_val, changed_sys_vars_))) {
      LOG_WARN("fail to add changed system var", K(sys_var_id), K(old_val), K(ret));
    } else {
      LOG_DEBUG("add changed var success", K(sys_var_id), K(old_val), K(changed_sys_vars_));
    }
  }
  return ret;
}

int ObBasicSessionInfo::track_user_var(const common::ObString &user_var)
{
  int ret = OB_SUCCESS;
  if (user_var.empty()) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid input value", K(user_var), K(ret));
  } else if (!is_already_tracked(user_var, changed_user_vars_)) {
    ObString name;
    if (OB_FAIL(ob_write_string(changed_var_pool_, user_var, name))) {
      LOG_WARN("fail to write string", K(user_var), K(ret));
    } else if (OB_FAIL(add_changed_user_var(name, changed_user_vars_))) {
      LOG_WARN("fail to add changed user var", K(name), K(ret));
    }
  }
  return ret;
}

int ObBasicSessionInfo::is_sys_var_actully_changed(const ObSysVarClassType &sys_var_id,
                                                   const ObObj &old_val,
                                                   ObObj &new_val,
                                                   bool &changed)
{
  int ret = OB_SUCCESS;
  // 部分系统变量除了设置标志位外还做了其他的工作
  // 因此这里仅CHECK只设置了标志位的系统变量
  // 变量的设置参考函数 process_session_variable
  changed = true;
  OZ (get_sys_variable(sys_var_id, new_val));
  if (OB_SUCC(ret)) {
    switch (sys_var_id) {
      case SYS_VAR_AUTO_INCREMENT_INCREMENT:
      case SYS_VAR_AUTO_INCREMENT_OFFSET:
      case SYS_VAR_LAST_INSERT_ID:
      case SYS_VAR_TX_READ_ONLY:
      case SYS_VAR_OB_ENABLE_PLAN_CACHE:
      case SYS_VAR_OB_ENABLE_SQL_AUDIT:
      case SYS_VAR_AUTOCOMMIT:
      case SYS_VAR_OB_ENABLE_SHOW_TRACE:
      case SYS_VAR_OB_ORG_CLUSTER_ID:
      case SYS_VAR_OB_QUERY_TIMEOUT:
      case SYS_VAR_OB_TRX_TIMEOUT:
      case SYS_VAR_OB_TRX_IDLE_TIMEOUT:
      case SYS_VAR_COLLATION_CONNECTION:
      case SYS_VAR_OB_PL_BLOCK_TIMEOUT:
      case SYS_VAR_OB_COMPATIBILITY_MODE:
      case SYS_VAR__OB_OLS_POLICY_SESSION_LABELS:
      case SYS_VAR__OB_PROXY_SESSION_TEMPORARY_TABLE_USED: {
       changed = old_val.get_meta() == new_val.get_meta() ? old_val != new_val : true;
      }
      break;
      default: {
        break;
      }
    }
  }
  LOG_DEBUG("is_sys_var_actully_changed", K(sys_var_id), K(changed), K(old_val), K(new_val));
  return ret;
}

int ObBasicSessionInfo::set_partition_hit(const bool is_hit)
{
  int ret = OB_SUCCESS;
  ObObj obj;
  obj.set_bool(is_hit);
  if (OB_FAIL(update_sys_variable(SYS_VAR_OB_PROXY_PARTITION_HIT, obj))) {
    LOG_WARN("fail to update_system_variable", K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::set_proxy_user_privilege(const int64_t user_priv_set)
{
  int ret = OB_SUCCESS;
  ObObj obj;
  obj.set_int(user_priv_set);
  if (OB_FAIL(update_sys_variable(SYS_VAR_OB_PROXY_USER_PRIVILEGE, obj))) {
    LOG_WARN("fail to update_system_variable", K(SYS_VAR_OB_PROXY_USER_PRIVILEGE), K(user_priv_set), K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::update_last_trace_id(const ObCurTraceId::TraceId &trace_id)
{
  int ret = OB_SUCCESS;
  const int64_t TEMP_STR_BUF_LEN = 128;
  // 128 is enough to tracd_id, or will be truncated
  char tmp_str_buf[TEMP_STR_BUF_LEN]; // no need init
  int64_t pos = trace_id.to_string(tmp_str_buf, TEMP_STR_BUF_LEN);
  ObString trace_id_str(static_cast<ObString::obstr_size_t>(pos), tmp_str_buf);

  ObObj obj;
  obj.set_string(ObVarcharType, trace_id_str);
  obj.set_collation_type(ObCharset::get_system_collation());
  if (OB_FAIL(update_sys_variable(SYS_VAR_OB_STATEMENT_TRACE_ID , obj))) {
    LOG_WARN("fail to update_system_variable", K(SYS_VAR_OB_STATEMENT_TRACE_ID), K(trace_id_str), K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::set_proxy_capability(const uint64_t cap)
{
  int ret = OB_SUCCESS;
  ObObj obj;
  obj.set_int(cap);
  if (OB_FAIL(update_sys_variable(SYS_VAR_OB_CAPABILITY_FLAG, obj))) {
    LOG_WARN("fail to update_system_variable", K(SYS_VAR_OB_CAPABILITY_FLAG), K(cap), K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::set_trans_specified(const bool is_spec)
{
  int ret = OB_SUCCESS;
  ObObj obj;
  obj.set_bool(is_spec);
  if (OB_FAIL(update_sys_variable(SYS_VAR_OB_PROXY_SET_TRX_EXECUTED, obj))) {
    LOG_WARN("fail to update_system_variable", K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::set_session_temp_table_used(const bool is_used)
{
  int ret = OB_SUCCESS;
  ObObj obj;
  obj.set_int(is_used);
  if (OB_FAIL(update_sys_variable(SYS_VAR__OB_PROXY_SESSION_TEMPORARY_TABLE_USED, obj))) {
    LOG_WARN("fail to update_system_variable", K(ret));
  }
  return ret;
}

int ObBasicSessionInfo::set_init_connect(const ObString &init_sql)
{
  int ret = OB_SUCCESS;
  ObObj obj;
  obj.set_string(ObVarcharType, init_sql);
  obj.set_collation_type(ObCharset::get_system_collation());
  if (OB_FAIL(update_sys_variable(SYS_VAR_INIT_CONNECT, obj))) {
    LOG_WARN("fail to update_system_variable", K(ret));
  } else {}
  return ret;
}

int ObBasicSessionInfo::save_trans_status()
{
  int ret = OB_SUCCESS;
  switch(trans_spec_status_) {
    case TRANS_SPEC_SET:
      ret = set_trans_specified(true);
      break;
    case TRANS_SPEC_COMMIT:
      ret = set_trans_specified(false);
      trans_spec_status_ = TRANS_SPEC_NOT_SET;
      break;
    case TRANS_SPEC_NOT_SET:
      // do nothing
      break;
    default:
      ret = OB_ERR_UNEXPECTED;
      LOG_ERROR("Unknown trans specified status", K(trans_spec_status_), K(ret));
      break;
  }
  return ret;
}

int ObBasicSessionInfo::get_character_set_client(ObCharsetType &character_set_client) const
{
  return get_charset_sys_var(SYS_VAR_CHARACTER_SET_CLIENT, character_set_client);
}

int ObBasicSessionInfo::get_character_set_connection(ObCharsetType &character_set_connection) const
{
  if (CHARSET_INVALID == (character_set_connection = sys_vars_cache_.get_character_set_connection())) {
    get_charset_sys_var(SYS_VAR_CHARACTER_SET_CONNECTION, character_set_connection);
  }
  return OB_SUCCESS;
}

int ObBasicSessionInfo::get_character_set_database(ObCharsetType &character_set_database) const
{
  return get_charset_sys_var(SYS_VAR_CHARACTER_SET_DATABASE, character_set_database);
}

int ObBasicSessionInfo::get_character_set_results(ObCharsetType &character_set_results) const
{
  if (CHARSET_INVALID == (character_set_results = sys_vars_cache_.get_character_set_results())) {
    get_charset_sys_var(SYS_VAR_CHARACTER_SET_RESULTS, character_set_results);
  }
  return OB_SUCCESS;
}

int ObBasicSessionInfo::get_character_set_server(ObCharsetType &character_set_server) const
{
  return get_charset_sys_var(SYS_VAR_CHARACTER_SET_SERVER, character_set_server);
}

int ObBasicSessionInfo::get_character_set_system(ObCharsetType &character_set_system) const
{
  return get_charset_sys_var(SYS_VAR_CHARACTER_SET_SYSTEM, character_set_system);
}

int ObBasicSessionInfo::get_character_set_filesystem(ObCharsetType &character_set_filesystem) const
{
  return get_charset_sys_var(SYS_VAR_CHARACTER_SET_FILESYSTEM, character_set_filesystem);
}

int ObBasicSessionInfo::get_collation_database(ObCollationType &collation_database) const
{
  return get_collation_sys_var(SYS_VAR_COLLATION_DATABASE, collation_database);
}

int ObBasicSessionInfo::get_collation_server(ObCollationType &collation_server) const
{
  return get_collation_sys_var(SYS_VAR_COLLATION_SERVER, collation_server);
}

int ObBasicSessionInfo::get_capture_plan_baseline(bool &v)  const
{
  v = sys_vars_cache_.get_optimizer_capture_sql_plan_baselines();
  return OB_SUCCESS;
}

int ObBasicSessionInfo::get_nlj_batching_enabled(bool &v) const
{
  return get_bool_sys_var(SYS_VAR__NLJ_BATCHING_ENABLED, v);
}

int ObBasicSessionInfo::get_auto_increment_cache_size(int64_t &auto_increment_cache_size)
{
  int ret = OB_SUCCESS;
  if (OB_FAIL(get_sys_variable(SYS_VAR_AUTO_INCREMENT_CACHE_SIZE, auto_increment_cache_size))) {
    LOG_WARN("fail to get variables", K(ret));
  }
  return ret;
}

int ObBasicSessionInfo::get_enable_parallel_dml(bool &v) const
{
  return get_bool_sys_var(SYS_VAR__ENABLE_PARALLEL_DML, v);
}

int ObBasicSessionInfo::get_enable_parallel_query(bool &v) const
{
  return get_bool_sys_var(SYS_VAR__ENABLE_PARALLEL_QUERY, v);
}

int ObBasicSessionInfo::get_enable_parallel_ddl(bool &v) const
{
  return get_bool_sys_var(SYS_VAR__ENABLE_PARALLEL_DDL, v);
}

int ObBasicSessionInfo::get_force_parallel_query_dop(uint64_t &v) const
{
  int ret = OB_SUCCESS;
  if (exec_min_cluster_version_ >= CLUSTER_VERSION_3100) {
    ret = get_uint64_sys_var(SYS_VAR__FORCE_PARALLEL_QUERY_DOP, v);
  } else {
    v = 1;
  }
  return ret;
}

int ObBasicSessionInfo::get_force_parallel_dml_dop(uint64_t &v) const
{
  int ret = OB_SUCCESS;
  if (exec_min_cluster_version_ >= CLUSTER_VERSION_3100) {
    ret = get_uint64_sys_var(SYS_VAR__FORCE_PARALLEL_DML_DOP, v);
  } else {
    v = 1;
  }
  return ret;
}

int ObBasicSessionInfo::get_force_parallel_ddl_dop(uint64_t &v) const
{
  int ret = OB_SUCCESS;
  if (exec_min_cluster_version_ >= CLUSTER_VERSION_3200) {
    ret = get_uint64_sys_var(SYS_VAR__FORCE_PARALLEL_DDL_DOP, v);
  } else {
    v = 1;
  }
  return ret;
}

int ObBasicSessionInfo::get_partial_rollup_pushdown(int64_t &partial_rollup) const
{
  int ret = OB_SUCCESS;
  ret = get_sys_variable(SYS_VAR__PX_PARTIAL_ROLLUP_PUSHDOWN, partial_rollup);
  return ret;
}

int ObBasicSessionInfo::get_distinct_agg_partial_rollup_pushdown(int64_t &partial_rollup) const
{
  int ret = OB_SUCCESS;
  ret = get_sys_variable(SYS_VAR__PX_DIST_AGG_PARTIAL_ROLLUP_PUSHDOWN, partial_rollup);
  return ret;
}

int ObBasicSessionInfo::get_px_shared_hash_join(bool &shared_hash_join) const
{
  int ret = OB_SUCCESS;
  ret = get_bool_sys_var(SYS_VAR__PX_SHARED_HASH_JOIN, shared_hash_join);
  return ret;
}

int ObBasicSessionInfo::get_sql_notes(bool &sql_notes) const
{
  int ret = OB_SUCCESS;
  ret = get_bool_sys_var(SYS_VAR_SQL_NOTES, sql_notes);
  return ret;
}

int ObBasicSessionInfo::get_secure_file_priv(ObString &v) const
{
  return get_string_sys_var(SYS_VAR_SECURE_FILE_PRIV, v);
}

int ObBasicSessionInfo::get_sql_safe_updates(bool &v) const
{
  return get_bool_sys_var(SYS_VAR_SQL_SAFE_UPDATES, v);
}

int ObBasicSessionInfo::get_session_temp_table_used(bool &is_used) const
{
  return get_bool_sys_var(SYS_VAR__OB_PROXY_SESSION_TEMPORARY_TABLE_USED, is_used);
}

int ObBasicSessionInfo::get_enable_optimizer_null_aware_antijoin(bool &is_enabled) const
{
  return get_bool_sys_var(SYS_VAR__OPTIMIZER_NULL_AWARE_ANTIJOIN, is_enabled);
}

// 重置事务相关变量
// 调用时机：end_trans阶段
//
// 注意：
// 1. 该函数需要保证幂等，可能在多处调用
// 2. trans_desc不能够在这里重置，end_trans过程中可能还会用到相关变量，
//    它由事务层在ObTransService::start_trans()中reset()
void ObBasicSessionInfo::reset_tx_variable()
{
  LOG_DEBUG("reset tx variable", K(lbt()));
  reset_tx_isolation();
  reset_tx_read_only();
  reset_trans_flags();
  clear_app_trace_id();
}

ObTxIsolationLevel ObBasicSessionInfo::get_tx_isolation() const
{
  ObTxIsolationLevel isolation;
  if (next_tx_isolation_ != ObTxIsolationLevel::INVALID) {
    isolation = next_tx_isolation_;
  } else {
    // 这里只会在本机调用，因此使用sys_vars_cache_data_的系统变量
    isolation = sys_vars_cache_.get_tx_isolation();
  }
  return isolation;
}

bool ObBasicSessionInfo::is_isolation_serializable() const
{
  return ObTxIsolationLevel::SERIAL == get_tx_isolation();
}

void ObBasicSessionInfo::set_tx_isolation(ObTxIsolationLevel isolation)
{
  if (isolation == ObTxIsolationLevel::INVALID) {
    LOG_ERROR("set invalid tx isolation", K(isolation), KPC(this));
  }
  next_tx_isolation_ = isolation;
  trans_spec_status_ = TRANS_SPEC_SET;
}

void ObBasicSessionInfo::reset_tx_isolation()
{
  next_tx_isolation_ = transaction::ObTxIsolationLevel::INVALID;
  if (TRANS_SPEC_SET == trans_spec_status_ ) {
    trans_spec_status_ = TRANS_SPEC_COMMIT;
  }
}

/*
 这里为什么每次都要设置next_tx_read_only？

 set session transaction read only;
 set transaction read write;
 start transaction;
 insert into tt values(5);
 insert into tt values(6);
 start transaction;        //隐式提交上面的事务，开启本事务，read_only=false;
 insert into tt values(8); //对于这种case，这条语句需要执行成功，与mysql保持兼容
 commit;

 为了保持上述行为跟mysql一致，不能做如下处理:
 if (last_tx_read_only != cur_tx_read_only) {
   next_tx_read_only_ = cur_tx_read_only;
   trans_spec_status_ = TRANS_SPEC_SET;
 }
 */
void ObBasicSessionInfo::set_tx_read_only(const bool last_tx_read_only, bool cur_tx_read_only)
{
  next_tx_read_only_ = cur_tx_read_only;
  if (last_tx_read_only != cur_tx_read_only) {
    trans_spec_status_ = TRANS_SPEC_SET;
  }
}

void ObBasicSessionInfo::reset_tx_read_only()
{
  next_tx_read_only_ = -1;
  if (TRANS_SPEC_SET == trans_spec_status_ ) {
    trans_spec_status_ = TRANS_SPEC_COMMIT;
  }
}


int ObBasicSessionInfo::check_tx_read_only_privilege(const ObSqlTraits &sql_traits)
{
  int ret = OB_SUCCESS;
  if (sql_traits.is_cause_implicit_commit_) {
    reset_tx_read_only();
  } else {}
  // pl call stmt and anonymous does not check here,
  // will be check in ObTransService::start_stmt_sanity_check_
  if (get_tx_read_only() && !sql_traits.is_readonly_stmt_
      && sql_traits.stmt_type_ != ObItemType::T_SP_CALL_STMT
      && sql_traits.stmt_type_ != ObItemType::T_SP_ANONYMOUS_BLOCK) {
    ret = OB_ERR_CANT_EXECUTE_IN_READ_ONLY_TRANSACTION;

  } else {}
  return ret;
}

int ObBasicSessionInfo::reset_tx_variable_if_remote_trans(const ObPhyPlanType& type)
{
  int ret = OB_SUCCESS;
  if (ObSqlTransUtil::is_remote_trans(get_local_autocommit(), is_in_transaction(), type)) {
    reset_tx_variable();
  } else {
    // nothing to do
  }
  return ret;
}

bool ObBasicSessionInfo::get_tx_read_only() const
{
  bool tx_read_only = false;
  const int32_t TX_NOT_SET = -1;
  if (next_tx_read_only_ != TX_NOT_SET) {
    tx_read_only = next_tx_read_only_;
  } else {
    // 这里只会在本机调用，因此使用sys_vars_cache_data_的系统变量
    tx_read_only = sys_vars_cache_.get_tx_read_only();
  }
  return tx_read_only;
}

int ObBasicSessionInfo::store_query_string(const ObString &stmt)
{
  LockGuard lock_guard(thread_data_mutex_);
  return store_query_string_(stmt);
}

int ObBasicSessionInfo::store_query_string_(const ObString &stmt)
{
  int ret = OB_SUCCESS;
  int64_t truncated_len = std::min(MAX_QUERY_STRING_LEN - 1,
                                   static_cast<int64_t>(stmt.length()));
  if (truncated_len < 0) {
    ret = OB_INVALID_ARGUMENT;
    LOG_WARN("invalid str length", K(ret), K(truncated_len));
  } else if (thread_data_.cur_query_buf_len_ - 1 < truncated_len) {
    if (thread_data_.cur_query_ != nullptr) {
      ob_free(thread_data_.cur_query_);
      thread_data_.cur_query_ = NULL;
      thread_data_.cur_query_buf_len_ = 0;
    }
    int64_t len = MAX(MIN_CUR_QUERY_LEN, truncated_len + 1);
     char *buf = reinterpret_cast<char*>(ob_malloc(len, ObModIds::OB_SQL_SESSION_QUERY_SQL));
    if (OB_ISNULL(buf)) {
      ret = OB_ALLOCATE_MEMORY_FAILED;
      LOG_WARN("alloc memory failed", K(ret));
    } else {
      thread_data_.cur_query_ = buf;
      thread_data_.cur_query_buf_len_ = len;
    }
  }
  if (OB_SUCC(ret)) {
    MEMCPY(thread_data_.cur_query_, stmt.ptr(), truncated_len);
    //char cur_query_[MAX_QUERY_STRING_LEN] 不存在越界风险,且不需要判空
    thread_data_.cur_query_[truncated_len] = '\0';
    thread_data_.cur_query_len_ = truncated_len;
  }
  return ret;
}

void ObBasicSessionInfo::reset_query_string()
{
  thread_data_.cur_query_[0] = '\0';
  thread_data_.cur_query_len_ = 0;
}

int ObBasicSessionInfo::update_session_timeout()
{
  int ret = OB_SUCCESS;
  ObObj val;
  if (thread_data_.is_interactive_) {
    val.set_int(thread_data_.interactive_timeout_);
    if (OB_FAIL(update_sys_variable(SYS_VAR_WAIT_TIMEOUT, val))) {
      LOG_WARN("failed to update session_timeout", K(ret));
    }
  }
  return ret;
}

const char *ObBasicSessionInfo::get_session_state_str()const
{
  const char *str_ret = NULL;
  switch (thread_data_.state_) {
    case SESSION_INIT:
      str_ret = "INIT";
      break;
    case SESSION_SLEEP:
      str_ret = "SLEEP";
      break;
    case QUERY_ACTIVE:
      str_ret = "ACTIVE";
      break;
    case QUERY_KILLED:
      str_ret = "QUERY_KILLED";
      break;
    case QUERY_DEADLOCKED:
      str_ret = "QUERY_DEADLOCKED";
      break;
    case SESSION_KILLED:
      str_ret = "SESSION_KILLED";
      break;
    default:
      str_ret = "INVALID SESSION STATE";
      break;
  }
  return str_ret;
}

int ObBasicSessionInfo::is_timeout(bool &is_timeout)
{
  int ret = OB_SUCCESS;
  int64_t timeout = 0;
  is_timeout = false;
  if (SESSION_SLEEP == thread_data_.state_) {
    timeout = thread_data_.is_interactive_ ?
        thread_data_.interactive_timeout_ : thread_data_.wait_timeout_;
    int64_t cur_time = ::oceanbase::common::ObTimeUtility::current_time();
    if (OB_UNLIKELY(timeout < 0)) {
      ret = OB_ERR_UNEXPECTED;
      LOG_ERROR("session timeout setting is invalid", K(ret), K(timeout));
    } else if (OB_UNLIKELY(timeout > INT64_MAX / 1000 / 1000)) {
      ret = OB_ERR_UNEXPECTED;
      LOG_ERROR("session timeout setting is too larger, skip check timeout", K(ret), K(timeout));
    } else if (0 == timeout) {
      // no timeout check for timeout == 0
    } else if (SESSION_SLEEP == thread_data_.state_
               && thread_data_.last_active_time_ + timeout * 1000 * 1000 < cur_time) {
      const ObString &user_name = get_user_name();
      char addr_buf[common::OB_IP_PORT_STR_BUFF];
      if (OB_FAIL(get_peer_addr().ip_port_to_string(addr_buf,
                                                    OB_IP_PORT_STR_BUFF))) {
        LOG_WARN("failed to get peer addr string", K(ret), K(get_peer_addr()), K(addr_buf));
      } else {
        _LOG_INFO("sessionkey %u, proxy_sessid %lu: %.*s from %s timeout: last active time=%s, cur=%s, timeout=%lds",
                  sessid_, proxy_sessid_, user_name.length(), user_name.ptr(), addr_buf,
                  time2str(thread_data_.last_active_time_), time2str(cur_time), timeout);
      }
      is_timeout = true;
    }
  }
  return ret;
}

// is_trx_commit_timeout - check txn committing reach either commit stmt's timeout or txn's timeout
//
// @callback: the callback supplied when call commit, it is canceled and return via this argument
// @retcode: timeout type, either OB_TRANS_STMT_TIMEOUT or OB_TRANS_TIMEOUT
int ObBasicSessionInfo::is_trx_commit_timeout(transaction::ObITxCallback *&callback, int &retcode)
{
  int ret = OB_SUCCESS;
  int64_t cur_time = ::oceanbase::common::ObTimeUtility::current_time();
  if (is_in_transaction() && tx_desc_->is_committing()) {
    if (tx_desc_->is_tx_timeout()) {
      callback = tx_desc_->cancel_commit_cb();
      retcode = OB_TRANS_TIMEOUT;
    } else if (tx_desc_->is_tx_commit_timeout()) {
      callback = tx_desc_->cancel_commit_cb();
      retcode = OB_TRANS_STMT_TIMEOUT;
    }
  }
  return ret;
}

// 检查事务内部的语句间隔超时
int ObBasicSessionInfo::is_trx_idle_timeout(bool &timeout)
{
  int ret = OB_SUCCESS;
  int64_t cur_time = ::oceanbase::common::ObTimeUtility::current_time();
  LOG_DEBUG("check trx_idle_timeout : ", K_(sessid),
            K(curr_trans_last_stmt_end_time_),
            K(cur_time), "start_time", get_query_start_time());
  if (get_query_start_time() < curr_trans_last_stmt_end_time_) {
    int64_t ob_trx_idle_timeout = sys_vars_cache_.get_ob_trx_idle_timeout() > 0
      ? sys_vars_cache_.get_ob_trx_idle_timeout() : 120 * 1000 * 1000;
    if (is_in_transaction() &&
        !tx_desc_->is_committing() &&
        curr_trans_last_stmt_end_time_ > 0 &&
        curr_trans_last_stmt_end_time_ + ob_trx_idle_timeout < cur_time) {
      LOG_WARN("ob_trx_idle_timeout happen", K_(sessid), K_(curr_trans_last_stmt_end_time), K(ob_trx_idle_timeout));
      curr_trans_last_stmt_end_time_ = 0; // flip
      timeout = true;
    }
  }
  return ret;
}

int ObBasicSessionInfo::get_pc_mem_conf(ObPCMemPctConf &pc_mem_conf)
{
  int ret = OB_SUCCESS;
  if (OB_FAIL(get_sys_variable(SYS_VAR_OB_PLAN_CACHE_PERCENTAGE, pc_mem_conf.limit_pct_))) {
    LOG_WARN("fail to get plan cache system variables",K(pc_mem_conf.limit_pct_), K(ret));
  } else if (OB_FAIL(get_sys_variable(SYS_VAR_OB_PLAN_CACHE_EVICT_HIGH_PERCENTAGE, pc_mem_conf.high_pct_))) {
    LOG_WARN("fail to get plan cache system variables",K(pc_mem_conf.high_pct_), K(ret));
  } else if (OB_FAIL(get_sys_variable(SYS_VAR_OB_PLAN_CACHE_EVICT_LOW_PERCENTAGE, pc_mem_conf.low_pct_))) {
    LOG_WARN("fail to get plan cache system variables",K(pc_mem_conf.low_pct_), K(ret));
  }
  return ret;
}

int ObBasicSessionInfo::get_sql_audit_mem_conf(int64_t &mem_pct)
{
  int ret = OB_SUCCESS;
  if (OB_FAIL(get_sys_variable(SYS_VAR_OB_SQL_AUDIT_PERCENTAGE, mem_pct))) {
    LOG_WARN("failed to get memory percentage for sql audit", K(ret));
  }
  return ret;
}

//session 当前的query处于非retry的packet处理时
//  1）如果thread_data_.state_ == SESSION_KILLED时，调用该接口直接返回OB_ERR_SESSION_INTERRUPTED错误；
//  2）如果thread_data_.state_ != SESSION_KILLED时，进行session state的设置

//session 当前的query处于retry的packet处理时
//  1）如果thread_data_.state_ == SESSION_KILLED时，调用该接口直接返回OB_ERR_SESSION_INTERRUPTED错误；
//  2）如果thread_data_.state_ != SESSION_KILLED时，则进一步判断
//     2.1)如果QUERY_KILLED == thread_data_.state_ && state != SESSION_KILLED, 则返回OB_ERR_QUERY_INTERRUPTED错误
//     2.2)如果QUERY_DEADLOCKED == thread_data_.state_ && state != SESSION_KILLED, 则返回OB_DEAD_LOCK错误
//     2.3)其他情况则进行session state的设置
int ObBasicSessionInfo::set_session_state(ObSQLSessionState state)
{
  LockGuard lock_guard(thread_data_mutex_);
  return set_session_state_(state);
}

int ObBasicSessionInfo::set_session_state_(ObSQLSessionState state)
{
  int ret = OB_SUCCESS;
  if (OB_UNLIKELY(SESSION_KILLED == thread_data_.state_)) {
    ret = OB_ERR_SESSION_INTERRUPTED;
    LOG_WARN("session is killed", K(ret), K(sessid_), K(proxy_sessid_), K(state));
  } else if (OB_UNLIKELY(SESS_NOT_IN_RETRY != thread_data_.is_in_retry_
                         && is_query_killed()
                         && SESSION_KILLED != state)) {
    if (QUERY_DEADLOCKED == thread_data_.state_) {
      ret = OB_DEAD_LOCK;
      LOG_WARN("query is deadlocked", K(ret), K(sessid_), K(proxy_sessid_), K(state));
    } else if (QUERY_KILLED == thread_data_.state_) {
      ret = OB_ERR_QUERY_INTERRUPTED;
      LOG_WARN("query is killed", K(ret), K(sessid_), K(proxy_sessid_), K(state));
    } else {
      ret = OB_ERR_UNEXPECTED;;
      LOG_WARN("session state is unknown", K(ret), K(sessid_), K(proxy_sessid_), K(state));
    }
  } else {
    thread_data_.state_ = state;
    thread_data_.cur_state_start_time_ = ::oceanbase::common::ObClockGenerator::getClock();
  }
  return ret;
}

// check the status of the session
// ATTENTION: the function only focus on the state
// will cause the query and session to be killed.
int ObBasicSessionInfo::check_session_status()
{
  int ret = OB_SUCCESS;

  if (OB_UNLIKELY(SESSION_KILLED == thread_data_.state_)) {
    ret = OB_ERR_SESSION_INTERRUPTED;
    LOG_WARN("session is killed", K(ret), K(sessid_), K(proxy_sessid_));
  } else if (OB_UNLIKELY(QUERY_KILLED == thread_data_.state_)) {
    ret = OB_ERR_QUERY_INTERRUPTED;
    LOG_WARN("query is killed", K(ret), K(sessid_), K(proxy_sessid_));
  } else if (OB_UNLIKELY(QUERY_DEADLOCKED == thread_data_.state_)) {
    ret = OB_DEAD_LOCK;
    LOG_WARN("query is deadlocked", K(ret), K(sessid_), K(proxy_sessid_));
  }

  return ret;
}

bool ObBasicSessionInfo::is_query_killed() const
{
  return QUERY_KILLED == get_session_state()
    || QUERY_DEADLOCKED == get_session_state();
}

int ObBasicSessionInfo::set_session_active(const ObString &sql,
                                           const int64_t query_receive_ts,
                                           const int64_t last_active_time_ts,
                                           obmysql::ObMySQLCmd cmd)
{
  int ret = OB_SUCCESS;
  LockGuard lock_guard(thread_data_mutex_);
  if (OB_FAIL(store_query_string_(sql))) {
    LOG_WARN("store query string fail", K(ret));
  } else if (OB_FAIL(set_session_state_(QUERY_ACTIVE))) {
    LOG_WARN("fail to set session state", K(ret));
  } else {
    thread_data_.cur_query_start_time_ = query_receive_ts;
    thread_data_.mysql_cmd_ = cmd;
    thread_data_.last_active_time_ = last_active_time_ts;
    ObActiveSessionGuard::setup_ash(ash_stat_);
  }
  return ret;
}

int ObBasicSessionInfo::set_session_active(const ObString &label,
                                           obmysql::ObMySQLCmd cmd)
{
  int ret = OB_SUCCESS;
  LockGuard lock_guard(thread_data_mutex_);
  if (OB_FAIL(store_query_string_(label))) {
    LOG_WARN("store query string fail", K(ret));
  } else if (OB_FAIL(set_session_state_(QUERY_ACTIVE))) {
    LOG_WARN("fail to set session state", K(ret));
  } else {
    thread_data_.mysql_cmd_ = cmd;
    ObActiveSessionGuard::setup_ash(ash_stat_);
  }
  return ret;
}

void ObBasicSessionInfo::set_session_sleep()
{
  LockGuard lock_guard(thread_data_mutex_);
  set_session_state_(SESSION_SLEEP);
  thread_data_.mysql_cmd_ = obmysql::COM_SLEEP;
  thread_id_ = 0;
}

int ObBasicSessionInfo::base_save_session(BaseSavedValue &saved_value, bool skip_cur_stmt_tables)
{
  int ret = OB_SUCCESS;
  OX (saved_value.cur_phy_plan_ = cur_phy_plan_);
  OX (cur_phy_plan_ = NULL);
  int len = MIN(thread_data_.cur_query_len_, static_cast<int64_t>(sizeof(saved_value.cur_query_) - 1));
  if (thread_data_.cur_query_ != nullptr) {
    OX (MEMCPY(&saved_value.cur_query_, thread_data_.cur_query_, len));
    OX (thread_data_.cur_query_[0] = 0);
  }
  OX (saved_value.cur_query_len_ = len);
  OX (thread_data_.cur_query_len_ = 0);
  OZ (saved_value.total_stmt_tables_.assign(total_stmt_tables_));
  if (!skip_cur_stmt_tables) {
    OZ (merge_stmt_tables(), total_stmt_tables_, cur_stmt_tables_);
  }
  OZ (saved_value.cur_stmt_tables_.assign(cur_stmt_tables_));
  OX (cur_stmt_tables_.reset());
  OX (sys_vars_cache_.get_autocommit_info(saved_value.inc_autocommit_));
  OX (sys_vars_cache_.set_autocommit_info(false));
  OX (saved_value.is_foreign_key_cascade_ = is_foreign_key_cascade_);
  OX (is_foreign_key_cascade_ = false);
  OX (saved_value.is_foreign_key_check_exist_ = is_foreign_key_check_exist_);
  OX (is_foreign_key_check_exist_ = false);
  OX (saved_value.need_serial_exec_ = trans_flags_.need_serial_exec());
  if (OB_NOT_NULL(saved_value.cur_phy_plan_) &&
      saved_value.cur_phy_plan_->get_need_serial_exec()) {
    OX (trans_flags_.set_need_serial_exec(true));
  }
  return ret;
}

int ObBasicSessionInfo::stmt_save_session(StmtSavedValue &saved_value, bool skip_cur_stmt_tables)
{
  int ret = OB_SUCCESS;
  OZ (base_save_session(saved_value, skip_cur_stmt_tables));
  OZ (saved_value.tx_result_.assign(tx_result_));
  OX (tx_result_.reset());
  OX (saved_value.cur_query_start_time_ = thread_data_.cur_query_start_time_);
  OX (thread_data_.cur_query_start_time_ = 0);
  OX (saved_value.stmt_type_ = stmt_type_);
  return ret;
}

int ObBasicSessionInfo::save_basic_session(StmtSavedValue &saved_value, bool skip_cur_stmt_tables)
{
  return stmt_save_session(saved_value, skip_cur_stmt_tables);
}

int ObBasicSessionInfo::begin_nested_session(StmtSavedValue &saved_value, bool skip_cur_stmt_tables)
{
  int ret = OB_SUCCESS;
  OZ (SMART_CALL(save_basic_session(saved_value, skip_cur_stmt_tables)));
  return ret;
}

int ObBasicSessionInfo::base_restore_session(BaseSavedValue &saved_value)
{
  int ret = OB_SUCCESS;
  OX (trans_flags_.set_need_serial_exec(saved_value.need_serial_exec_));
  OX (is_foreign_key_check_exist_ = saved_value.is_foreign_key_check_exist_);
  OX (is_foreign_key_cascade_ = saved_value.is_foreign_key_cascade_);
  OX (sys_vars_cache_.set_autocommit_info(saved_value.inc_autocommit_));
  OZ (cur_stmt_tables_.assign(saved_value.cur_stmt_tables_));
  OZ (total_stmt_tables_.assign(saved_value.total_stmt_tables_));
//OX (thread_data_.cur_query_start_time_ = saved_value.cur_query_start_time_);
  int64_t len = MIN(saved_value.cur_query_len_, thread_data_.cur_query_buf_len_ - 1);
  OX (thread_data_.cur_query_len_ = len);
  if (thread_data_.cur_query_ != nullptr) {
    OX (MEMCPY(thread_data_.cur_query_, saved_value.cur_query_, len));
    thread_data_.cur_query_[len] = '\0';
  }
  OX (cur_phy_plan_ = saved_value.cur_phy_plan_);
  return ret;
}

int ObBasicSessionInfo::stmt_restore_session(StmtSavedValue &saved_value)
{
  int ret = OB_SUCCESS;
  OX (thread_data_.cur_query_start_time_ = saved_value.cur_query_start_time_);
  OZ (tx_result_.merge_result(saved_value.tx_result_));
  OZ (base_restore_session(saved_value));
  OX (stmt_type_ = saved_value.stmt_type_);
  return ret;
}

int ObBasicSessionInfo::restore_basic_session(StmtSavedValue &saved_value)
{
  return stmt_restore_session(saved_value);
}

int ObBasicSessionInfo::end_nested_session(StmtSavedValue &saved_value)
{
  int ret = OB_SUCCESS;
  OZ (SMART_CALL(restore_basic_session(saved_value)));
  OX (saved_value.reset());
  return ret;
}

int ObBasicSessionInfo::trans_save_session(TransSavedValue &saved_value)
{
  int ret = OB_SUCCESS;
  OZ (base_save_session(saved_value, false));
  /*
   * save transaction context
   */
  OX (saved_value.tx_desc_ = tx_desc_);
  OX (tx_desc_ = NULL);
  OZ (saved_value.tx_result_.assign(tx_result_));
  OX (tx_result_.reset());
  OX (saved_value.trans_flags_ = trans_flags_);
  OX (trans_flags_.reset());
  OX (saved_value.nested_count_ = nested_count_);
  OX (nested_count_ = -1);
  return ret;
}

int ObBasicSessionInfo::trans_restore_session(TransSavedValue &saved_value)
{
  int ret = OB_SUCCESS;
  OX (nested_count_ = saved_value.nested_count_);
  OX (trans_flags_ = saved_value.trans_flags_);
  /*
   * restore means switch to saved transaction context, drop current one.
   */
  OZ (tx_result_.assign(saved_value.tx_result_));
  OX (tx_desc_ = saved_value.tx_desc_);
  OZ (base_restore_session(saved_value));
  return ret;
}

int ObBasicSessionInfo::begin_autonomous_session(TransSavedValue &saved_value)
{
  return trans_save_session(saved_value);
}

int ObBasicSessionInfo::end_autonomous_session(TransSavedValue &saved_value)
{
  return trans_restore_session(saved_value);
}

int ObBasicSessionInfo::set_start_stmt()
{
  int ret = OB_SUCCESS;
  OV (nested_count_ == -1, OB_ERR_UNEXPECTED, nested_count_);
  OX (nested_count_ = 0);
  return ret;
}

int ObBasicSessionInfo::set_end_stmt()
{
  int ret = OB_SUCCESS;
  OV (nested_count_ == 0, OB_ERR_UNEXPECTED, nested_count_);
  OX (nested_count_ = -1);
  return ret;
}

int ObBasicSessionInfo::init_stmt_tables()
{
  int ret = OB_SUCCESS;
  if (!is_nested_session() && !is_fast_select()) {
    // cur stmt is top stmt.
    total_stmt_tables_.reset();
    cur_stmt_tables_.reset();
  }
  return ret;
}

int ObBasicSessionInfo::check_stmt_table(uint64_t table_id, stmt::StmtType stmt_type)
{
  int ret = OB_SUCCESS;
  TableStmtType table_stmt_type(table_id, stmt_type);
  int64_t idx = -1;
  if (!is_nested_session() && !is_fast_select()) {
    // check nested stmt and fast select only, skip for top stmt.
    // fast select is used by cursor only NOW
  } else if (!is_foreign_key_cascade() && !is_foreign_key_check_exist()) {
    if (has_exist_in_array(total_stmt_tables_, table_stmt_type, &idx) &&
        0 <= idx && idx < total_stmt_tables_.count()) {
      if (total_stmt_tables_.at(idx).is_mutating()) {
        ObSchemaGetterGuard schema_guard;
        const ObTableSchema *table_schema = NULL;
        OZ (GCTX.schema_service_->get_tenant_schema_guard(
            effective_tenant_id_, schema_guard));
        OZ (schema_guard.get_table_schema(effective_tenant_id_, table_id, table_schema));
        CK (OB_NOT_NULL(table_schema));
        if (OB_SUCC(ret) && lib::is_mysql_mode()) {
          LOG_MYSQL_USER_ERROR(OB_ERR_MUTATING_TABLE_OPERATION, table_schema->get_table_name());
        }
        ret = OB_ERR_MUTATING_TABLE_OPERATION;
        LOG_WARN("table is mutating", K(table_stmt_type), K(ret));
      }
    }
  }
  if (!need_serial_exec()) {
    // skip those stmts which will NOT execute nested stmt.
    // ps: need_serial_exec flag is introduced for nested stmt rollback.
  } else if (has_exist_in_array(cur_stmt_tables_, table_stmt_type, &idx) &&
             0 <= idx && idx < cur_stmt_tables_.count()) {
    // in dml plan, dml op and table scan op have same table_id, and they will both
    // call check_stmt_table(), so we need rewrite stmt_type if current is SELECT.
    if (cur_stmt_tables_.at(idx).get_stmt_type() == stmt::T_SELECT) {
      OX (cur_stmt_tables_.at(idx).set_stmt_type(stmt_type));
    }
  } else {
    OZ (cur_stmt_tables_.push_back(table_stmt_type), table_id, stmt_type);
  }
  return ret;
}

int ObBasicSessionInfo::merge_stmt_tables()
{
  int ret = OB_SUCCESS;
  int64_t idx = -1;
  for (int i = 0; OB_SUCC(ret) && i < cur_stmt_tables_.count(); i++) {
    idx = -1;
    OZ (add_var_to_array_no_dup(total_stmt_tables_, cur_stmt_tables_.at(i), &idx));
    if (0 <= idx && idx < total_stmt_tables_.count()) {
      OX (total_stmt_tables_.at(idx).set_stmt_type(cur_stmt_tables_.at(i).get_stmt_type()));
    }
  }
  return ret;
}

int ObBasicSessionInfo::skip_mutating(uint64_t table_id, stmt::StmtType &saved_stmt_type)
{
  int ret = OB_SUCCESS;
  int64_t idx = -1;
  TableStmtType table_stmt_type(table_id);
  if (has_exist_in_array(cur_stmt_tables_, table_stmt_type, &idx) &&
      0 <= idx && idx < cur_stmt_tables_.count()) {
    OX (cur_stmt_tables_.at(idx).skip_mutating(saved_stmt_type));
  }
  return ret;
}

int ObBasicSessionInfo::restore_mutating(uint64_t table_id, stmt::StmtType saved_stmt_type)
{
  int ret = OB_SUCCESS;
  int64_t idx = -1;
  TableStmtType table_stmt_type(table_id);
  if (has_exist_in_array(cur_stmt_tables_, table_stmt_type, &idx) &&
      0 <= idx && idx < cur_stmt_tables_.count()) {
    OX (cur_stmt_tables_.at(idx).restore_mutating(saved_stmt_type));
  }
  return ret;
}

int ObBasicSessionInfo::set_time_zone(const ObString &str_val, const bool is_oralce_mode,
                                     const bool check_timezone_valid)
{
  int ret = OB_SUCCESS;
  int32_t offset = 0;
  int ret_more = OB_SUCCESS;

  if (OB_FAIL(ObTimeConverter::str_to_offset(str_val, offset, ret_more,
                                                    is_oralce_mode, check_timezone_valid))) {
    if (ret != OB_ERR_UNKNOWN_TIME_ZONE) {
      LOG_WARN("fail to convert time zone", K(str_val), K(ret));
    }
  } else {
    tz_info_wrap_.set_tz_info_offset(offset);
  }

  if (OB_ERR_UNKNOWN_TIME_ZONE == ret) {
    ObTZMapWrap tz_map_wrap;
    ObTimeZoneInfoManager *tz_info_mgr = NULL;
    if (OB_FAIL(OTTZ_MGR.get_tenant_timezone(tenant_id_, tz_map_wrap, tz_info_mgr))) {
      LOG_WARN("get tenant timezone with lock failed", K(ret));
    } else if (OB_ISNULL(tz_info_mgr)) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("tenant timezone mgr is null", K(tz_info_mgr));
    } else {//此处需要先更新version，这样可以保证find到的tz_info version >= cur_version
      const int64_t orig_version = tz_info_wrap_.get_cur_version();
      tz_info_wrap_.set_cur_version(tz_info_mgr->get_version());
      ObCollationType coll_type = ObCharset::get_default_collation(ObCharset::get_default_charset());
      int32_t no_sp_len = static_cast<int32_t>(ObCharset::strlen_byte_no_sp(coll_type,
                                                                            str_val.ptr(),
                                                                            str_val.length()));
      ObString val_no_sp(no_sp_len, str_val.ptr());
      if (is_oralce_mode) {
        val_no_sp = val_no_sp.trim();
      }
      //note:要先获取start service time；如果先find再获取start_service_time，start_service_time可能在这个时间窗口中被更改
      int64_t start_service_time = GCTX.start_service_time_;
      if (OB_FAIL(tz_info_mgr->find_time_zone_info(val_no_sp,
                                                   tz_info_wrap_.get_tz_info_pos()))) {
        LOG_WARN("fail to find time zone", K(str_val), K(val_no_sp), K(ret));
        tz_info_wrap_.set_cur_version(orig_version);
      } else {
        tz_info_wrap_.set_tz_info_position();
      }

      if (OB_ERR_UNKNOWN_TIME_ZONE == ret) {
        if (0 == start_service_time) {
          //代码执行到这里有两种情况：1）session的反序列化逻辑；2）系统租户的登陆流程
          //对于第二中情况，期待该session上的后续query会促使session更新timezone info，因此这里对timezone信息进行设置
          LOG_INFO("ignore unknow time zone, perhaps in remote/distribute task processer when server start_time is zero", K(str_val));
          offset = 0;
          if (OB_FAIL(ObTimeConverter::str_to_offset(ObString("+8:00"), offset, ret_more,
                                                    is_oralce_mode, check_timezone_valid))) {
            if (ret != OB_ERR_UNKNOWN_TIME_ZONE) {
              LOG_WARN("fail to convert time zone", K(str_val), K(ret));
            }
          } else {
            tz_info_wrap_.set_tz_info_offset(offset);
          }
        }
      }

    }
  }
  return ret;
}

int ObBasicSessionInfo::update_timezone_info()
{
  int ret = OB_SUCCESS;
  ObTZMapWrap tz_map_wrap;
  ObTimeZoneInfoManager *tz_info_mgr = NULL;
  if (OB_FAIL(OTTZ_MGR.get_tenant_timezone(tenant_id_, tz_map_wrap, tz_info_mgr))) {
    LOG_WARN("get tenant timezone with lock failed", K(ret));
  } else if (OB_ISNULL(tz_info_mgr)) {
    ret = OB_ERR_UNEXPECTED;
    LOG_WARN("tenant timezone mgr is null", K(tz_info_mgr));
  } else if (OB_UNLIKELY(tz_info_wrap_.is_position_class()
              && tz_info_mgr->get_version() > tz_info_wrap_.get_cur_version())) {
    ObString tz_name;
    if (OB_UNLIKELY(!tz_info_wrap_.get_tz_info_pos().is_valid())) {
      ret = OB_ERR_UNEXPECTED;
      LOG_WARN("time zone info is invalid", K(tz_info_wrap_.get_tz_info_pos()), K(ret));
    } else if (OB_FAIL(tz_info_wrap_.get_tz_info_pos().get_tz_name(tz_name))) {
      LOG_WARN("fal to get time zone name", K(tz_info_wrap_.get_tz_info_pos()), K(ret));
    } else {//此处需要先更新version，这样可以保证find到的tz_info version >= cur_version
      int64_t orig_version = tz_info_wrap_.get_cur_version();
      tz_info_wrap_.set_cur_version(tz_info_mgr->get_version());
      if (OB_FAIL(tz_info_mgr->find_time_zone_info(tz_name, tz_info_wrap_.get_tz_info_pos()))) {
        LOG_WARN("fail to find time zone info", K(tz_name), K(ret));
        tz_info_wrap_.set_cur_version(orig_version);
      } else {
        tz_info_wrap_.get_tz_info_pos().set_error_on_overlap_time(tz_info_wrap_.is_error_on_overlap_time());
      }
    }
  }
  return ret;
}

constexpr ObSysVarClassType ObExecEnv::ExecEnvMap[MAX_ENV + 1];

void ObExecEnv::reset()
{
  sql_mode_ = DEFAULT_OCEANBASE_MODE;
  charset_client_ = CS_TYPE_INVALID;
  collation_connection_ = CS_TYPE_INVALID;
  collation_database_ = CS_TYPE_INVALID;
  plsql_ccflags_.reset();
}

bool ObExecEnv::operator==(const ObExecEnv &other) const
{
  return sql_mode_ == other.sql_mode_
      && charset_client_ == other.charset_client_
      && collation_connection_ == other.collation_connection_
      && collation_database_ == other.collation_database_
      && plsql_ccflags_ == other.plsql_ccflags_;
}

bool ObExecEnv::operator!=(const ObExecEnv &other) const
{
  return !(*this == other);
}

int ObExecEnv::gen_exec_env(const ObBasicSessionInfo &session, char* buf, int64_t len, int64_t &pos)
{
  int ret = OB_SUCCESS;
  ObObj val;
  for (int64_t i = 0; OB_SUCC(ret) && i < MAX_ENV; ++i) {
    switch (i) {
      case PLSQL_CCFLAGS: {
        if (lib::is_oracle_mode()) { // plsql_ccflags only in oracle mode!
          int64_t size = 0;
          val.reset();
          OZ (session.get_sys_variable(ExecEnvMap[i], val));
          // note: plsql_ccflags max length is 256 bytes, buffer size is 2048 bytes.
          ObString plsql_ccflags = val.get_varchar();
          // print length of plsql_ccflags
          OZ (databuff_printf(
            buf + pos, len - pos, size, "%d", static_cast<int32_t>(plsql_ccflags.length())));
          OX (pos += size);
          CK (pos < len);
          OX (buf[pos++] = ',');
          // print content of plsql_ccflags
          OX (size = 0);
          OZ (databuff_printf(buf + pos, len - pos, size, "%.*s",
                              static_cast<int32_t>(plsql_ccflags.length()), plsql_ccflags.ptr()));
          OX (pos += size);
          CK (pos < len);
          OX (buf[pos++] = ',');
        }
      } break;
      case SQL_MODE:
      case CHARSET_CLIENT:
      case COLLATION_CONNECTION:
      case COLLATION_DATABASE: {
        int64_t size = 0;
        val.reset();
        OZ (session.get_sys_variable(ExecEnvMap[i], val));
        OZ (val.print_plain_str_literal(buf + pos, len - pos, size));
        //输出间隔符
        OX (pos += size);
        CK (pos < len);
        OX (buf[pos++] = ',');
      } break;
      default: {
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("unexpected evn type found!", K(ret), K(i));
      }
    }
  }
  return ret;
}

int ObExecEnv::gen_exec_env(const share::schema::ObSysVariableSchema &sys_variable,
                            char* buf,
                            int64_t len,
                            int64_t &pos)
{
  int ret = OB_SUCCESS;
  ObObj val;
  bool is_oracle_mode = false;
  if (OB_FAIL(sys_variable.get_oracle_mode(is_oracle_mode))) {
    LOG_WARN("failed to get oracle mode", K(ret));
  }
  for (int64_t i = 0; OB_SUCC(ret) && i < MAX_ENV; ++i) {
    const ObSysVarSchema *sysvar_schema = nullptr;
    switch (i) {
      case PLSQL_CCFLAGS: {
        if (is_oracle_mode) { // plsql_ccflags only in oracle mode!
          int64_t size = 0;
          if (OB_FAIL(sys_variable.get_sysvar_schema(ExecEnvMap[i], sysvar_schema))) {
            LOG_WARN("failed to get sysvar schema", K(ret));
          } else if (OB_ISNULL(sysvar_schema)) {
            ret = OB_ERR_UNEXPECTED;
            LOG_WARN("get unexpected null", K(ret), K(sysvar_schema));
          } else {
            ObString plsql_ccflags = sysvar_schema->get_value();
            // print length of plsql_ccflags
            OZ (databuff_printf(buf + pos, len - pos, size, "%d",
                                static_cast<int32_t>(plsql_ccflags.length())));
            OX (pos += size);
            CK (pos < len);
            OX (buf[pos++] = ',');
            // print content of plsql_ccflags
            OX (size = 0);
            OZ (databuff_printf(buf + pos, len - pos, size, "%.*s",
                                static_cast<int32_t>(plsql_ccflags.length()), plsql_ccflags.ptr()));
            OX (pos += size);
            CK (pos < len);
            OX (buf[pos++] = ',');
          }
        }
      } break;
      case SQL_MODE:
      case CHARSET_CLIENT:
      case COLLATION_CONNECTION:
      case COLLATION_DATABASE: {
        int64_t size = 0;
        if (OB_FAIL(sys_variable.get_sysvar_schema(ExecEnvMap[i], sysvar_schema))) {
          LOG_WARN("failed to get sysvar schema", K(ret));
        } else if (OB_ISNULL(sysvar_schema)) {
          ret = OB_ERR_UNEXPECTED;
          LOG_WARN("get unexpected null", K(ret), K(sysvar_schema));
        } else {
          ObString val = sysvar_schema->get_value();
          OZ (databuff_printf(buf + pos, len - pos, size, "%.*s",
                                                    static_cast<int32_t>(val.length()), val.ptr()));
          OX (pos += size);
          //输出间隔符
          CK (pos < len);
          OX (buf[pos++] = ',');
        }
      } break;
      default: {
        ret = OB_ERR_UNEXPECTED;
        LOG_WARN("unexpected evn type found!", K(ret), K(i));
      }
    }
  }
  return ret;
}

#define GET_ENV_VALUE(start, value)                                           \
  do {                                                                        \
    const char *end = NULL;                                                   \
    value_str.reset();                                                        \
    if (!start.empty()) {                                                     \
      OX (end = start.find(','));                                             \
      CK (end != NULL);                                                       \
      OX (value.assign(                                                       \
        start.ptr(), static_cast<ObString::obstr_size_t>(end - start.ptr())));\
      OX (start = start.after(','));                                          \
    }                                                                         \
  } while (0)

#define SET_ENV_VALUE(env, type)                                              \
  do {                                                                        \
    int64_t value = 0;                                                        \
    int64_t pos = 0;                                                          \
    if (OB_FAIL(ret)) {                                                       \
    } else if (OB_FAIL(extract_int(value_str, 0, pos, value))) {              \
      LOG_WARN("Failed to extract int", K(value_str), K(ret));                \
    } else {                                                                  \
      env = static_cast<type>(value);                                         \
    }                                                                         \
  } while (0)

int ObExecEnv::init(const ObString &exec_env)
{
  int ret = OB_SUCCESS;
  ObString value_str;
  ObString start = exec_env;
  for (int64_t i = 0; OB_SUCC(ret) && i < MAX_ENV; ++i) {
    GET_ENV_VALUE(start, value_str);
    if (OB_SUCC(ret)) {
      switch (i) {
      case SQL_MODE: {
        SET_ENV_VALUE(sql_mode_, ObSQLMode);
      }
      break;
      case CHARSET_CLIENT: {
        SET_ENV_VALUE(charset_client_, ObCollationType);
      }
      break;
      case COLLATION_CONNECTION: {
        SET_ENV_VALUE(collation_connection_, ObCollationType);
      }
      break;
      case COLLATION_DATABASE: {
        SET_ENV_VALUE(collation_database_, ObCollationType);
      }
      break;
      case PLSQL_CCFLAGS: {
        if (start.empty()) {
          // do nothing, old routine object version do not have plsql_ccflags.
        } else {
          int32_t plsql_ccflags_length = 0;
          SET_ENV_VALUE(plsql_ccflags_length, int32_t);
          if (OB_FAIL(ret)) {
          } else if (plsql_ccflags_length > 0) {
            plsql_ccflags_.assign(start.ptr(), plsql_ccflags_length);
            start += plsql_ccflags_length + 1;// 1 for ','
          }
        }
      }
      break;
      default: {
        ret = common::OB_ERR_UNEXPECTED;
        LOG_WARN("Invalid env type", K(exec_env), K(i), K(ret));
      }
      break;
      }
    }
  }
  return ret;
}

#undef SET_ENV_VALUE
#undef GET_ENV_VALUE

int ObExecEnv::load(ObBasicSessionInfo &session)
{
  int ret = OB_SUCCESS;
  ObObj val;
  for (int64_t i = 0; OB_SUCC(ret) && i < MAX_ENV; ++i) {
    val.reset();
    if (lib::is_mysql_mode() && PLSQL_CCFLAGS == i) {
      // do nothing ...
    } else if (OB_FAIL(session.get_sys_variable(ExecEnvMap[i], val))) {
      LOG_WARN("failed to get sys_variable", K(ExecEnvMap[i]), K(ret));
    } else {
      switch (i) {
      case SQL_MODE: {
        sql_mode_ = static_cast<ObSQLMode>(val.get_int());
      }
      break;
      case CHARSET_CLIENT: {
        charset_client_ = static_cast<ObCollationType>(val.get_int());
      }
      break;
      case COLLATION_CONNECTION: {
        collation_connection_ = static_cast<ObCollationType>(val.get_int());
      }
      break;
      case COLLATION_DATABASE: {
        collation_database_ = static_cast<ObCollationType>(val.get_int());
      }
      break;
      case PLSQL_CCFLAGS: {
        plsql_ccflags_ = val.get_varchar();
      }
      break;
      default: {
        ret = common::OB_ERR_UNEXPECTED;
        LOG_WARN("Invalid env type", K(i), K(ret));
      }
      break;
      }
    }
  }
  return ret;
}

int ObExecEnv::store(ObBasicSessionInfo &session)
{
  int ret = OB_SUCCESS;
  ObObj val;
  for (int64_t i = 0; OB_SUCC(ret) && i < MAX_ENV; ++i) {
    val.reset();
    switch (i) {
    case SQL_MODE: {
      val.set_uint64(sql_mode_);
    }
    break;
    case CHARSET_CLIENT: {
      val.set_int(charset_client_);
    }
    break;
    case COLLATION_CONNECTION: {
      val.set_int(collation_connection_);
    }
    break;
    case COLLATION_DATABASE: {
      val.set_int(collation_database_);
    }
    break;
    case PLSQL_CCFLAGS: {
      val.set_varchar(plsql_ccflags_);
      val.set_collation_type(ObCharset::get_system_collation());
    }
    break;
    default: {
      ret = common::OB_ERR_UNEXPECTED;
      LOG_WARN("Invalid env type", K(i), K(ret));
    }
    break;
    }
    if (OB_FAIL(ret)) {
    } else if (lib::is_mysql_mode() && PLSQL_CCFLAGS == i) {
      // do nothing ...
    } else if (OB_FAIL(session.update_sys_variable(ExecEnvMap[i], val))) {
      LOG_WARN("failed to get sys_variable", K(ExecEnvMap[i]), K(ret));
    }
  }
  return ret;
}

void ObBasicSessionInfo::on_get_session()
{
  const char *str = lbt();
  int len = STRLEN(str);
  if (sess_bt_buff_pos_ + len + 2 < MAX_SESS_BT_BUFF_SIZE) {
    MEMCPY(sess_bt_buff_ + sess_bt_buff_pos_, str, len);
    sess_bt_buff_pos_ += len;
    sess_bt_buff_[sess_bt_buff_pos_] = ';';
    sess_bt_buff_pos_ += 1;
    sess_bt_buff_[sess_bt_buff_pos_] = '\0';
  }
  (void)ATOMIC_AAF(&sess_ref_cnt_, 1);
  (void)ATOMIC_AAF(&sess_ref_seq_, 1);
  LOG_INFO("on get session", KP(this), K(sess_ref_cnt_), K(sess_ref_seq_),
                             K(sessid_), "backtrace", ObString(len, str));
}

void ObBasicSessionInfo::on_revert_session()
{
  int32_t v = ATOMIC_AAF(&sess_ref_cnt_, -1);
  if (v <= 0) {
    sess_bt_buff_pos_ = 0;
    sess_bt_buff_[0] = '\0';
  }
  LOG_INFO("on revert session", KP(this), K(sess_ref_cnt_), K(sess_ref_seq_),
                                K(sessid_), "backtrace", lbt());
}

}//end of namespace sql
}//end of namespace oceanbase