From 8ab24c71d012cc5547ba1098b3a350f3d4f94b5a Mon Sep 17 00:00:00 2001
From: kailixu <klxu@taosdata.com>
Date: Mon, 13 May 2024 17:14:29 +0800
Subject: [PATCH] fix: show tags from undefined table

---
 source/libs/parser/src/parAstParser.c        |  4 +++
 source/libs/parser/src/parTranslater.c       | 28 +++++++++++++++++++-
 tests/system-test/0-others/show_tag_index.py |  6 +++++
 3 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/source/libs/parser/src/parAstParser.c b/source/libs/parser/src/parAstParser.c
index 3da6ac668c..ef9252e337 100644
--- a/source/libs/parser/src/parAstParser.c
+++ b/source/libs/parser/src/parAstParser.c
@@ -534,6 +534,10 @@ static int32_t collectMetaKeyFromShowTables(SCollectMetaKeyCxt* pCxt, SShowStmt*
 static int32_t collectMetaKeyFromShowTags(SCollectMetaKeyCxt* pCxt, SShowStmt* pStmt) {
   int32_t code = reserveTableMetaInCache(pCxt->pParseCxt->acctId, TSDB_INFORMATION_SCHEMA_DB, TSDB_INS_TABLE_TAGS,
                                          pCxt->pMetaCache);
+  if (TSDB_CODE_SUCCESS == code) {
+    code = reserveTableMetaInCache(pCxt->pParseCxt->acctId, ((SValueNode*)pStmt->pDbName)->literal,
+                                   ((SValueNode*)pStmt->pTbName)->literal, pCxt->pMetaCache);
+  }
   if (TSDB_CODE_SUCCESS == code) {
     code = reserveDbVgInfoInCache(pCxt->pParseCxt->acctId, ((SValueNode*)pStmt->pDbName)->literal, pCxt->pMetaCache);
   }
diff --git a/source/libs/parser/src/parTranslater.c b/source/libs/parser/src/parTranslater.c
index b26f837423..68e207e64e 100644
--- a/source/libs/parser/src/parTranslater.c
+++ b/source/libs/parser/src/parTranslater.c
@@ -11867,6 +11867,30 @@ static int32_t rewriteShowVgroups(STranslateContext* pCxt, SQuery* pQuery) {
   return code;
 }
 
+static int32_t checkShowTags(STranslateContext* pCxt, const SShowStmt* pShow) {
+  int32_t     code = 0;
+  SName       name;
+  STableMeta* pTableMeta = NULL;
+  code = getTargetMeta(pCxt,
+                       toName(pCxt->pParseCxt->acctId, ((SValueNode*)pShow->pDbName)->literal,
+                              ((SValueNode*)pShow->pTbName)->literal, &name),
+                       &pTableMeta, true);
+  taosMemoryFreeClear(pTableMeta);
+  if (TSDB_CODE_SUCCESS != code) {
+    return generateSyntaxErrMsg(&pCxt->msgBuf, TSDB_CODE_PAR_GET_META_ERROR, tstrerror(code));
+  }
+
+  return code;
+}
+
+static int32_t rewriteShowTags(STranslateContext* pCxt, SQuery* pQuery) {
+  int32_t code = checkShowTags(pCxt, (SShowStmt*)pQuery->pRoot);
+  if (TSDB_CODE_SUCCESS == code) {
+    code = rewriteShow(pCxt, pQuery);
+  }
+  return code;
+}
+
 static SNode* createTagsFunction() {
   SFunctionNode* pFunc = (SFunctionNode*)nodesMakeNode(QUERY_NODE_FUNCTION);
   if (NULL == pFunc) {
@@ -13170,7 +13194,6 @@ static int32_t rewriteQuery(STranslateContext* pCxt, SQuery* pQuery) {
     case QUERY_NODE_SHOW_APPS_STMT:
     case QUERY_NODE_SHOW_CONSUMERS_STMT:
     case QUERY_NODE_SHOW_SUBSCRIPTIONS_STMT:
-    case QUERY_NODE_SHOW_TAGS_STMT:
     case QUERY_NODE_SHOW_USER_PRIVILEGES_STMT:
     case QUERY_NODE_SHOW_VIEWS_STMT:
     case QUERY_NODE_SHOW_GRANTS_FULL_STMT:
@@ -13181,6 +13204,9 @@ static int32_t rewriteQuery(STranslateContext* pCxt, SQuery* pQuery) {
     case QUERY_NODE_SHOW_TSMAS_STMT:
       code = rewriteShow(pCxt, pQuery);
       break;
+    case QUERY_NODE_SHOW_TAGS_STMT:
+      code = rewriteShowTags(pCxt, pQuery);
+      break;
     case QUERY_NODE_SHOW_VGROUPS_STMT:
       code = rewriteShowVgroups(pCxt, pQuery);
       break;
diff --git a/tests/system-test/0-others/show_tag_index.py b/tests/system-test/0-others/show_tag_index.py
index c79880ba35..3f1b598589 100644
--- a/tests/system-test/0-others/show_tag_index.py
+++ b/tests/system-test/0-others/show_tag_index.py
@@ -113,6 +113,9 @@ class TDTestCase:
         tdSql.error(f'show tags from `db`.`stb` from db')
         tdSql.error(f'show tags from db.ctb1 from db')
         tdSql.error(f'show tags from `db`.`ctb1` from db')
+        tdSql.error(f'show tags from tb_undef from db')
+        tdSql.error(f'show tags from db.tb_undef')
+        tdSql.error(f'show tags from tb_undef')
 
         # show table tags
         tdSql.query(f'show table tags from stb')
@@ -145,6 +148,9 @@ class TDTestCase:
         tdSql.error(f'show table tags from `db`.`stb` from db')
         tdSql.error(f'show table tags from db.ctb1 from db')
         tdSql.error(f'show table tags from `db`.`ctb1` from db')
+        tdSql.error(f'show table tags from tb_undef from db')
+        tdSql.error(f'show table tags from db.tb_undef')
+        tdSql.error(f'show table tags from tb_undef')
 
         # show indexes
         tdSql.execute(f'create index idx1 on stb (t1)')