[CP] implement dblink reuse connection cfg

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

@@ -376,6 +376,7 @@ int ObLruConnectionAllocator<T>::free_session_conn_array(uint32_t sessid, int64_
     _OB_LOG(DEBUG, "try to free conn_array, conn_array=%p, count=%ld", conn_array, array_size);
     while (OB_SUCC(ret) && OB_SUCCESS == conn_array->pop_back(conn)) {
       conn->close(); //close immedately
+      _OB_LOG(TRACE, "close connection, conn=%p", conn);
       if (OB_FAIL(free_conn_array_.push_back(conn))) {
         ret = OB_ALLOCATE_MEMORY_FAILED;
         _OB_LOG(WARN, "push_back conn to free_conn_array_ failed, sessid=%u, ret=%d", sessid, ret);
@@ -390,6 +391,7 @@ int ObLruConnectionAllocator<T>::free_session_conn_array(uint32_t sessid, int64_
       fail_recycled_conn_count = array_size - succ_count;
       while (OB_SUCCESS == conn_array->pop_back(conn)) {
         conn->close(); //close immedately
+        _OB_LOG(TRACE, "close connection, conn=%p", conn);
         ObLruConnectionAllocator<T>::free(conn);
       }
       if (OB_SUCCESS != sessionid_to_conns_map_.erase_refactored(sessid)) {
@@ -465,9 +467,11 @@ int ObLruConnectionAllocator<T>::get_cached(T *&conn, uint32_t sessid)
     } else if (OB_FAIL(conn_array_erase(conn_array, conn))) {
       ObLruConnectionAllocator<T>::free(conn);
       _OB_LOG(WARN, "failed to erase conn from conn_array, other_sessid=%u, sessid=%u, ret=%d", other_sessid, sessid, ret);
-    } else if (!is_session_share_conns_) { // get conn from other seesion, need close it.
+    } else if (!is_session_share_conns_) {
-      conn->close();
+      conn->set_sessid(0);
-      _OB_LOG(TRACE, "get conn from other seesion, need close it, other_sessid=%u, sessid=%u, ret=%d", other_sessid, sessid, ret);
+      // get conn from other seesion, set sessid as 0,
+      // and will close it at ObServerConnectionPool::acquire() and int ObOciServerConnectionPool::acquire(ObOciConnection *&conn, uint32_t sessid).
+      _OB_LOG(TRACE, "get conn from other seesion, other_sessid=%u, sessid=%u, ret=%d", other_sessid, sessid, ret);
     }
   } else if (NULL == conn) {
     ret = OB_ERR_UNEXPECTED;

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

@@ -34,6 +34,10 @@ const char* __attribute__((weak)) get_mysql_str_error(int index)
   return NULL;
 }
 
+bool __attribute__((weak)) get_dblink_reuse_connection_cfg()
+{
+  return true;
+}
 
 namespace oceanbase
 {

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

@@ -15,6 +15,8 @@
 #include "lib/utility/ob_edit_distance.h"
 #include "lib/ob_errno.h"
 
+extern bool get_dblink_reuse_connection_cfg();
+
 namespace oceanbase
 {
 namespace common

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

@@ -88,17 +88,20 @@ int ObServerConnectionPool::acquire(ObMySQLConnection *&conn, uint32_t sessid)
   }
   if (OB_SUCC(ret)) {
     conn = connection;
-    conn->set_sessid(sessid);
     if (conn->connection_version() != connection_version_) {
       conn->set_connection_version(connection_version_);
       conn->close();
+    } else if (sessid != conn->get_sessid()) {
+      LOG_TRACE("get connection from other session, close it", K(ret), K(sessid), K(conn->get_sessid()));
+      conn->close();
     } else if (false == conn->is_closed()) {
       if (OB_SUCCESS != conn->ping()) {
         conn->close();
       }
     }
+    conn->set_sessid(sessid);
   }
-  LOG_TRACE("acquire connection from server conn pool", KP(this), K(busy_conn_count_), K(free_conn_count_), KP(connection), K(ret), K(lbt()));
+  LOG_TRACE("acquire connection from server conn pool", KP(this), K(busy_conn_count_), K(free_conn_count_), KP(connection), K(ret), K(sessid), K(lbt()));
   return ret;
 }
 
@@ -111,20 +114,27 @@ int ObServerConnectionPool::release(common::sqlclient::ObISQLConnection *conn, c
     LOG_WARN("invalid connection", K(connection), K(ret));
   } else {
     connection->set_busy(false);
-    ObSpinLockGuard lock(pool_lock_);
     if (succ) {
       connection->succ_times_++;
+      if (!get_dblink_reuse_connection_cfg()) {
+        connection->close();
+        LOG_TRACE("close dblink connection when release it", K(ret), K(succ), KP(conn));
+      }
     } else {
-      LOG_TRACE("release! err", K(succ));
+      LOG_TRACE("release oci connection, close it caused by err", K(succ));
       connection->error_times_++;
       connection->close();
     }
-    if (OB_FAIL(connection_pool_ptr_->put_cached(connection, connection->get_sessid()))) {
+    {
-      ATOMIC_DEC(&busy_conn_count_);
+      // Do not perform any operations on the network after thread holding a lock
-      LOG_WARN("connection object failed to put to cache. destroyed", K(ret));
+      ObSpinLockGuard lock(pool_lock_);
-    } else {
+      if (OB_FAIL(connection_pool_ptr_->put_cached(connection, connection->get_sessid()))) {
-      ATOMIC_DEC(&busy_conn_count_);
+        ATOMIC_DEC(&busy_conn_count_);
-      ATOMIC_INC(&free_conn_count_);
+        LOG_WARN("connection object failed to put to cache. destroyed", K(ret));
+      } else {
+        ATOMIC_DEC(&busy_conn_count_);
+        ATOMIC_INC(&free_conn_count_);
+      }
     }
   }
   LOG_TRACE("release connection to server conn pool", KP(this),

src/share/parameter/ob_parameter_seed.ipp

@@ -1679,7 +1679,9 @@ DEF_STR_WITH_CHECKER(rpc_server_authentication_method, OB_CLUSTER_PARAMETER, "AL
 DEF_BOOL(_enable_backtrace_function, OB_CLUSTER_PARAMETER, "True",
          "Decide whether to let the backtrace function take effect",
          ObParameterAttr(Section::OBSERVER, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));
-
+DEF_BOOL(_enable_dblink_reuse_connection, OB_TENANT_PARAMETER, "True",
+         "specifies whether dblink reuse connection in a session",
+         ObParameterAttr(Section::TENANT, Source::DEFAULT, EditLevel::DYNAMIC_EFFECTIVE));
 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));

src/sql/dblink/ob_dblink_utils.cpp

@@ -30,6 +30,14 @@ using namespace oceanbase::sql;
 using namespace oceanbase::share;
 
 #ifdef OB_BUILD_DBLINK
+
+bool get_dblink_reuse_connection_cfg()
+{
+  omt::ObTenantConfigGuard tenant_config(TENANT_CONF(MTL_ID()));
+  // default value of _enable_dblink_reuse_connection is true, if !tenant_config.is_valid() return true
+  return tenant_config.is_valid() ? tenant_config->_enable_dblink_reuse_connection : true;
+}
+
 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

@@ -279,6 +279,7 @@ _enable_block_file_punch_hole
 _enable_column_store
 _enable_compaction_diagnose
 _enable_convert_real_to_decimal
+_enable_dblink_reuse_connection
 _enable_decimal_int_type
 _enable_defensive_check
 _enable_easy_keepalive