Merge pull request #22031 from taosdata/enh/TS-2500

enh: add show create database command for system dbs

source/libs/command/src/command.c

@@ -286,6 +286,9 @@ static void setCreateDBResultIntoDataBlock(SSDataBlock* pBlock, char* dbName, ch
     hashPrefix = pCfg->hashPrefix + dbFNameLen + 1;
   }
 
+  if (IS_SYS_DBNAME(dbName)) {
+    len += sprintf(buf2 + VARSTR_HEADER_SIZE, "CREATE DATABASE `%s`", dbName);
+  } else {
     len += sprintf(
         buf2 + VARSTR_HEADER_SIZE,
         "CREATE DATABASE `%s` BUFFER %d CACHESIZE %d CACHEMODEL '%s' COMP %d DURATION %dm "
@@ -301,6 +304,7 @@ static void setCreateDBResultIntoDataBlock(SSDataBlock* pBlock, char* dbName, ch
       len += sprintf(buf2 + VARSTR_HEADER_SIZE + len, " RETENTIONS %s", retentions);
       taosMemoryFree(retentions);
     }
+  }
 
   (varDataLen(buf2)) = len;
 

source/libs/parser/src/parTranslater.c

@@ -509,6 +509,10 @@ static int32_t getDBVgVersion(STranslateContext* pCxt, const char* pDbFName, int
 }
 
 static int32_t getDBCfg(STranslateContext* pCxt, const char* pDbName, SDbCfgInfo* pInfo) {
+  if (IS_SYS_DBNAME(pDbName)) {
+    return TSDB_CODE_SUCCESS;
+  }
+
   SParseContext* pParCxt = pCxt->pParseCxt;
   SName          name;
   tNameSetDbName(&name, pCxt->pParseCxt->acctId, pDbName, strlen(pDbName));

tests/system-test/0-others/show.py

@@ -87,6 +87,14 @@ class TDTestCase:
         for key,value in sql_dict.items():
             create_sql += f' {key} {value}'
         return create_sql
+
+    def show_create_sysdb_sql(self):
+        sysdb_list = {'information_schema', 'performance_schema'}
+        for db in sysdb_list:
+          tdSql.query(f'show create database {db}')
+          tdSql.checkEqual(f'{db}',tdSql.queryResult[0][0])
+          tdSql.checkEqual(f'CREATE DATABASE `{db}`',tdSql.queryResult[0][1])
+
     def show_create_sql(self):
         create_db_sql = self.set_create_database_sql(self.db_param)
         print(create_db_sql)
@@ -191,6 +199,7 @@ class TDTestCase:
         self.ins_check()
         self.perf_check()
         self.show_create_sql()
+        self.show_create_sysdb_sql()
 
     def stop(self):
         tdSql.close()