fix memory leak when unit migrate or del tenant happens

src/observer/omt/ob_multi_tenant.cpp

@@ -415,6 +415,9 @@ int ObMultiTenant::add_tenant(const uint64_t tenant_id, const double min_cpu, co
                OB_FAIL(OTC_MGR.got_version(tenant_id, common::ObSystemConfig::INIT_VERSION))) {
       LOG_ERROR("failed to got version", K(tenant_id), K(ret));
 #endif
+    } else if (OB_FAIL(GCTX.sql_engine_->get_plan_cache_manager()->validate_plan_cache(tenant_id))) {
+      // do nothing
+      LOG_WARN("failed to active plan cache", K(ret), K(tenant_id));
     } else {
       LOG_INFO("activate tenant done", K(tenant_id), K(ret));
     }

src/observer/virtual_table/ob_all_plan_cache_stat.cpp

@@ -334,6 +334,8 @@ int ObAllPlanCacheStat::get_row_from_tenants()
       ObPlanCache* plan_cache = pcm_->get_plan_cache(tenant_id);
       if (OB_UNLIKELY(NULL == plan_cache)) {
         SERVER_LOG(WARN, "invalid plan cache", K(ret), K(tenant_id));
+      } else if (!plan_cache->is_valid()) {
+        // do nothing
       } else {
         if (OB_FAIL(fill_cells(*plan_cache))) {
           SERVER_LOG(WARN, "fail to fill cells", K(ret), K(cur_row_));

src/sql/ob_sql.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.

src/sql/plan_cache/ob_cache_object_factory.cpp

@@ -106,7 +106,9 @@ int ObCacheObjectFactory::alloc(
        * then the atomicity of hashmap can ensure that only one thread does the removal action, and
        * only this thread gets the CacheObject pointer to do subsequent destructuring
        */
-      if (OB_FAIL(plan_cache->get_deleted_map().set_refactored(cache_obj_id, cache_obj))) {
+      if (!plan_cache->is_valid()) {
+        // do nothing
+      } else if (OB_FAIL(plan_cache->get_deleted_map().set_refactored(cache_obj_id, cache_obj))) {
         LOG_WARN("failed to add element to hashmap", K(ret));
         inner_free(cache_obj);
         cache_obj = NULL;

src/sql/plan_cache/ob_plan_cache.cpp

@@ -1080,7 +1080,9 @@ void ObPlanCache::dec_ref_count()
   if (ref_count > 0) {
   } else if (0 == ref_count) {
     // delete
-    this->~ObPlanCache();
+    this->set_valid(false);
+    destroy();
+    // this->~ObPlanCache();
   } else if (ref_count < 0) {
     BACKTRACE(ERROR, true, "Plan Cache %p ref count < 0, ref_count = %ld", this, ref_count);
   }

src/sql/plan_cache/ob_plan_cache_manager.cpp

@@ -109,6 +109,20 @@ ObPsCache* ObPlanCacheManager::get_ps_cache(const uint64_t tenant_id)
   return ps_cache;
 }
 
+int ObPlanCacheManager::validate_plan_cache(const uint64_t& tenant_id)
+{
+  int ret = OB_SUCCESS;
+
+  ObPlanCache* plan_cache = get_plan_cache(tenant_id);
+  if (OB_ISNULL(plan_cache)) {
+    // do nothing, and others will create this later.
+  } else {
+    plan_cache->set_valid(true);
+  }
+
+  return ret;
+}
+
 //  maybe get plan_cache = NULL;
 //    this thread                    other thread
 //
@@ -251,7 +265,7 @@ int ObPlanCacheManager::revert_plan_cache(const uint64_t& tenant_id)
   int ret = OB_SUCCESS;
   ObPlanCache* ppc = NULL;
   observer::ObReqTimeGuard req_timeinfo_guard;
-  int tmp_ret = pcm_.erase_refactored(tenant_id, &ppc);
+  int tmp_ret = pcm_.get_refactored(tenant_id, ppc);
   if (OB_SUCCESS == tmp_ret && NULL != ppc) {
     SQL_PC_LOG(INFO, "plan_cache_manager revert plan cache", "pc ref_count", ppc->get_ref_count(), K(tenant_id));
     // cancel scheduled task

src/sql/plan_cache/ob_plan_cache_manager.h

@@ -82,6 +82,7 @@ public:
   ObPlanCache* get_or_create_plan_cache(uint64_t tenant_id, const ObPCMemPctConf& pc_mem_conf);
   ObPsCache* get_or_create_ps_cache(const uint64_t tenant_id, const ObPCMemPctConf& pc_mem_conf);
 
+  int validate_plan_cache(const uint64_t& tenant_id);
   int revert_plan_cache(const uint64_t& tenant_id);
   int revert_ps_cache(const uint64_t& tenant_id);
   int flush_all_plan_cache();

src/sql/session/ob_sql_session_info.cpp

@@ -611,7 +611,7 @@ void ObSQLSessionInfo::get_session_priv_info(share::schema::ObSessionPrivInfo& s
 ObPlanCache* ObSQLSessionInfo::get_plan_cache()
 {
   if (OB_LIKELY(NULL != plan_cache_manager_)) {
-    if (OB_NOT_NULL(plan_cache_) && plan_cache_->is_valid()) {
+    if (OB_NOT_NULL(plan_cache_)) {
       // do nothing
     } else {
       // release old plancache and get new