diff --git a/src/share/ob_debug_sync_point.h b/src/share/ob_debug_sync_point.h
index 9a2acebd41..67aaa48b5e 100755
--- a/src/share/ob_debug_sync_point.h
+++ b/src/share/ob_debug_sync_point.h
@@ -325,6 +325,7 @@ class ObString;
     ACT(DDL_REDEFINITION_HOLD_SNAPSHOT,)\
     ACT(DDL_REDEFINITION_WRITE_BARRIER_LOG,)\
     ACT(BEFORE_DDL_TABLE_MERGE_TASK,)\
+    ACT(BEFORE_LOB_META_TABELT_DDL_MERGE_TASK,)\
     ACT(TABLE_REDEFINITION_REPLICA_BUILD,)\
     ACT(TABLE_REDEFINITION_COPY_TABLE_INDEXES,)\
     ACT(TABLE_REDEFINITION_COPY_TABLE_FOREIGN_KEYS,)\
diff --git a/src/storage/ddl/ob_ddl_merge_task.cpp b/src/storage/ddl/ob_ddl_merge_task.cpp
index 4dfe5193b4..1f77ebdc35 100644
--- a/src/storage/ddl/ob_ddl_merge_task.cpp
+++ b/src/storage/ddl/ob_ddl_merge_task.cpp
@@ -288,6 +288,12 @@ int ObDDLTableMergeTask::process()
     LOG_WARN("get ddl sstable handles failed", K(ret));
   } else {
     DEBUG_SYNC(BEFORE_DDL_TABLE_MERGE_TASK);
+#ifdef ERRSIM
+    if (GCONF.errsim_test_tablet_id.get_value() > 0 && merge_param_.tablet_id_.id() == GCONF.errsim_test_tablet_id.get_value()) {
+      LOG_INFO("test tablet ddl merge start", K(ret), K(merge_param_));
+      DEBUG_SYNC(BEFORE_LOB_META_TABELT_DDL_MERGE_TASK);
+    }
+#endif
 #ifdef ERRSIM
     static int64_t counter = 0;
     counter++;