add _max_dblink_conn_per_observer cfg.

deps/oblib/src/lib/mysqlclient/ob_dblink_error_trans.cpp

@@ -44,6 +44,11 @@ bool __attribute__((weak)) get_enable_dblink_cfg()
   return true;
 }
 
+uint64_t __attribute__((weak)) get_max_dblink_conn_per_observer()
+{
+  return 256;
+}
+
 namespace oceanbase
 {
 namespace common

deps/oblib/src/lib/mysqlclient/ob_dblink_error_trans.h

@@ -5,6 +5,7 @@
 
 extern bool get_dblink_reuse_connection_cfg();
 extern bool get_enable_dblink_cfg();
+extern uint64_t get_max_dblink_conn_per_observer();
 
 namespace oceanbase
 {

deps/oblib/src/lib/mysqlclient/ob_server_connection_pool.cpp

@@ -210,6 +210,7 @@ int ObServerConnectionPool::init_dblink(uint64_t tenant_id, uint64_t dblink_id,
                                         ObMySQLConnectionPool *root, int64_t max_allowed_conn_count)
 {
   UNUSED(conn_str);
+  UNUSED(max_allowed_conn_count);
   int ret = OB_SUCCESS;
   if (OB_ISNULL(root)) {
     ret = OB_INVALID_ARGUMENT;
@@ -236,7 +237,7 @@ int ObServerConnectionPool::init_dblink(uint64_t tenant_id, uint64_t dblink_id,
     root_ = root;
     last_renew_timestamp_ = ::oceanbase::common::ObTimeUtility::current_time();
     server_not_available_ = false;
-    max_allowed_conn_count_ = max_allowed_conn_count;
+    max_allowed_conn_count_ = get_max_dblink_conn_per_observer();
     connection_pool_ptr_ = &dblink_connection_pool_;
     if (cluster_str.empty()) {
       (void)snprintf(db_user_, sizeof(db_user_), "%.*s@%.*s", db_user.length(), db_user.ptr(),

src/share/parameter/ob_parameter_seed.ipp

@@ -1667,7 +1667,9 @@ DEF_BOOL(_enable_dblink_reuse_connection, OB_TENANT_PARAMETER, "True",
 DEF_INT(_with_subquery, OB_TENANT_PARAMETER, "0", "[0,2]",
         "WITH subquery transformation,0: optimizer,1: materialize,2: inline",
         ObParameterAttr(Section::TENANT, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));
-
+DEF_INT(_max_dblink_conn_per_observer, OB_TENANT_PARAMETER, "256", "[0,)",
+        "The maximum limit on the number of connections that can be opened simultaneously for a specific observer for any DBLink, default value is 256",
+        ObParameterAttr(Section::TENANT, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));
 DEF_BOOL(_xsolapi_generate_with_clause, OB_TENANT_PARAMETER, "True",
         "OLAP API generates WITH clause",
         ObParameterAttr(Section::TENANT, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));

src/sql/dblink/ob_dblink_utils.cpp

@@ -43,6 +43,12 @@ bool get_enable_dblink_cfg()
   return GCONF.enable_dblink;
 }
 
+uint64_t get_max_dblink_conn_per_observer()
+{
+   omt::ObTenantConfigGuard tenant_config(TENANT_CONF(MTL_ID()));
+  return tenant_config.is_valid() ? tenant_config->_max_dblink_conn_per_observer : 256;
+}
+
 uint64_t ObDblinkService::get_current_tenant_id()
 {
   return MTL_ID();

tools/deploy/mysql_test/test_suite/inner_table/r/mysql/all_virtual_sys_parameter_stat.result

@@ -341,6 +341,7 @@ _load_tde_encrypt_engine
 _log_writer_parallelism
 _ls_gc_wait_readonly_tx_time
 _ls_migration_wait_completing_timeout
+_max_dblink_conn_per_observer
 _max_elr_dependent_trx_count
 _max_ls_cnt_per_server
 _max_malloc_sample_interval