diff --git a/src/sql/engine/table/ob_link_scan_op.cpp b/src/sql/engine/table/ob_link_scan_op.cpp
index 2ecd50238d..bedf24548c 100644
--- a/src/sql/engine/table/ob_link_scan_op.cpp
+++ b/src/sql/engine/table/ob_link_scan_op.cpp
@@ -135,6 +135,11 @@ int ObLinkScanOp::free_snapshot()
     if (OB_FAIL(ob_oci_conn->free_snapshot(snapshot_created_))) {
       LOG_WARN("set conn snapshot failed", K(ret));
     }
+    int tmp_ret = OB_SUCCESS;
+    hash::ObHashMap<uint64_t, void*> &dblink_snapshot_map = ctx_.get_dblink_snapshot_map();
+    if (OB_SUCCESS != (tmp_ret = dblink_snapshot_map.erase_refactored(dblink_id_))) {
+      LOG_WARN("failed to erase snapshot in map", K(tmp_ret), K(dblink_id_), K(ret));
+    }
     snapshot_created_ = NULL;
   }
   return ret;
@@ -212,23 +217,33 @@ int ObLinkScanOp::inner_execute_link_stmt(const char *link_stmt)
   return ret;
 }
 
-void ObLinkScanOp::reset_dblink()
+void ObLinkScanOp::reset_oci_connection()// once read oracle, once reset oci connection
 {
   int tmp_ret = OB_SUCCESS;
 #ifdef OB_BUILD_DBLINK
   if (DBLINK_DRV_OCI == link_type_ &&
-      NULL != dblink_conn_) {
-    if (OB_SUCCESS != (tmp_ret = static_cast<ObOciConnection *>(dblink_conn_)->free_oci_stmt())) {
-      LOG_WARN_RET(tmp_ret, "failed to close oci result", K(tmp_ret));
-    }
-    if (OB_UNLIKELY(OB_SUCCESS != (tmp_ret = free_snapshot()))) {
-      LOG_WARN_RET(tmp_ret, "free dblink snapshot failed");
-    }
+      NULL != dblink_conn_ &&
+      OB_SUCCESS != (tmp_ret = static_cast<ObOciConnection *>(dblink_conn_)->free_oci_stmt())) {
+    LOG_WARN_RET(tmp_ret, "failed to close oci result", K(tmp_ret));
   } else if (NULL != tm_rm_connection_ &&
              DblinkDriverProto::DBLINK_DRV_OCI == tm_rm_connection_->get_dblink_driver_proto() &&
              OB_SUCCESS != (tmp_ret = static_cast<ObOciConnection *>(tm_rm_connection_)->free_oci_stmt())) {
     LOG_WARN_RET(tmp_ret, "failed to close oci result", K(tmp_ret));
   }
+#endif
+}
+
+void ObLinkScanOp::reset_dblink()
+{
+  int tmp_ret = OB_SUCCESS;
+#ifdef OB_BUILD_DBLINK
+  reset_oci_connection();
+  // free oci snapshot when operator close
+  if (DBLINK_DRV_OCI == link_type_ &&
+      NULL != dblink_conn_ &&
+      OB_UNLIKELY(OB_SUCCESS != (tmp_ret = free_snapshot()))) {
+      LOG_WARN_RET(tmp_ret, "free dblink snapshot failed");
+  }
 #endif
   if (OB_NOT_NULL(dblink_proxy_) && OB_NOT_NULL(dblink_conn_) && !in_xa_trascaction_ &&
              OB_SUCCESS != (tmp_ret = dblink_proxy_->release_dblink(link_type_, dblink_conn_))) {
@@ -398,6 +413,7 @@ int ObLinkScanOp::fetch_row()
       LOG_WARN("failed to get next row", K(ret));
     } else {
       reset_result();
+      reset_oci_connection();
     }
   } else {
     const ObIArray<ObExpr *> &select_exprs =
@@ -464,18 +480,11 @@ int ObLinkScanOp::inner_close()
 int ObLinkScanOp::inner_rescan()
 {
   reset_result();
+  reset_oci_connection();
   reset_link_sql();
   iter_end_ = false;
   iterated_rows_ = -1;
   int tmp_ret = OB_SUCCESS;
-#ifdef OB_BUILD_DBLINK
-  if (DBLINK_DRV_OCI == link_type_ &&
-      NULL != dblink_conn_) {
-    if (OB_SUCCESS != (tmp_ret = static_cast<ObOciConnection *>(dblink_conn_)->free_oci_stmt())) {
-      LOG_WARN_RET(tmp_ret, "failed to close oci result", K(tmp_ret));
-    }
-  }
-#endif
   return ObOperator::inner_rescan();
 }
 
diff --git a/src/sql/engine/table/ob_link_scan_op.h b/src/sql/engine/table/ob_link_scan_op.h
index 42f636937e..7d9a7a4444 100644
--- a/src/sql/engine/table/ob_link_scan_op.h
+++ b/src/sql/engine/table/ob_link_scan_op.h
@@ -52,6 +52,7 @@ public:
 private:
   virtual void reset_dblink() override;
   void reset_result();
+  void reset_oci_connection();
   int init_conn_snapshot(bool &new_snapshot);
   int free_snapshot();
   bool need_tx(const ObSQLSessionInfo *my_session) const;