support show triggers for mysqldump

src/sql/resolver/cmd/ob_show_resolver.cpp

@@ -749,7 +749,28 @@ int ObShowResolver::resolve(const ParseNode& parse_tree)
         break;
       }
       case T_SHOW_TRIGGERS: {
-        ret = OB_NOT_SUPPORTED;
+        // Trigger is not supported in mysql mode and this is only used for mysqldump tool now.
+        // https://work.aone.alibaba-inc.com/issue/21188380
+        if (is_oracle_mode) {
+          ret = OB_NOT_SUPPORTED;
+          LOG_WARN("not support show triggers in oracle mode", K(ret));
+        } else if (OB_UNLIKELY(parse_tree.num_child_ != 2 || NULL == parse_tree.children_)) {
+          ret = OB_ERR_UNEXPECTED;
+          LOG_WARN("parse tree is wrong",
+              K(ret),
+              K(parse_tree.num_child_),
+              K(parse_tree.children_));
+        } else {
+          if (OB_FAIL(sql_gen.init(params_.allocator_))) {
+            LOG_WARN("fail to init sql string generator", K(ret));
+          } else if (OB_FAIL(sql_gen.gen_select_str(ObShowSqlSet::SHOW_TRIGGERS_SELECT))) {
+            LOG_WARN("fail to generate select string", K(ret));
+          } else if (OB_FAIL(sql_gen.gen_from_str(ObShowSqlSet::SHOW_TRIGGERS_SUBQUERY))) {
+            LOG_WARN("fail to generate from string", K(ret));
+          } else {
+            sql_gen.assign_sql_str(select_sql);
+          }
+        }
         break;
       }
       case T_SHOW_WARNINGS:

src/sql/resolver/ob_resolver.cpp

@@ -575,6 +575,7 @@ int ObResolver::resolve(IsPrepared if_prepared, const ParseNode& parse_tree, ObS
       case T_SHOW_CREATE_TENANT:
       case T_SHOW_RECYCLEBIN:
       case T_SHOW_CREATE_TABLEGROUP:
+      case T_SHOW_TRIGGERS:
       case T_SHOW_STATUS: {
         REGISTER_STMT_RESOLVER(Show);
         break;