add show command for system db

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 "
@@ -302,6 +305,7 @@ 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));