diff --git a/src/sql/engine/cmd/ob_tenant_executor.cpp b/src/sql/engine/cmd/ob_tenant_executor.cpp
index e4f0f7d92f..af884fed12 100644
--- a/src/sql/engine/cmd/ob_tenant_executor.cpp
+++ b/src/sql/engine/cmd/ob_tenant_executor.cpp
@@ -494,6 +494,9 @@ int modify_progressive_merge_num_for_tenant(ObExecContext &ctx,
               if (table->is_tmp_table()) {
                 do_alter = false;
               }
+              if (table->is_external_table()) {
+                do_alter = false;
+              }
               if (do_alter) {
                 ObSqlString sql;
                 int64_t affected_rows = 0;