[TD-4199]<feature> enhance performance

src/client/src/tscServer.c

@@ -2844,15 +2844,11 @@ int32_t tscGetTableMetaImpl(SSqlObj* pSql, STableMetaInfo *pTableMetaInfo, bool
   tNameExtractFullName(&pTableMetaInfo->name, name);
 
   size_t len = strlen(name);
+  if (pTableMetaInfo->tableMetaCapacity != 0) {
+    memset(pTableMetaInfo->pTableMeta, 0, pTableMetaInfo->tableMetaCapacity);
+  } 
   taosHashGetCloneExt(tscTableMetaMap, name, len, NULL, (void **)&(pTableMetaInfo->pTableMeta), &pTableMetaInfo->tableMetaCapacity);
 
-  // TODO resize the tableMeta
-  //assert(size < 80 * TSDB_MAX_COLUMNS);
-  //if (!pSql->pBuf) {
-  //  if (NULL == (pSql->pBuf = tcalloc(1, 80 * TSDB_MAX_COLUMNS))) {
-  //    return TSDB_CODE_TSC_OUT_OF_MEMORY;
-  //  }
-  //}
   STableMeta* pMeta = pTableMetaInfo->pTableMeta;
   if (pMeta && pMeta->id.uid > 0) {
     // in case of child table, here only get the

src/client/src/tscUtil.c

@@ -4460,17 +4460,19 @@ int32_t tscCreateTableMetaFromSTableMeta(STableMeta** ppChild, const char* name,
   // tableMeta exists, build child table meta according to the super table meta
   // the uid need to be checked in addition to the general name of the super table.
   if (p && p->id.uid > 0 && pChild->suid == p->id.uid) {
-    pChild->sversion = p->sversion;
-    pChild->tversion = p->tversion;
 
-    memcpy(&pChild->tableInfo, &p->tableInfo, sizeof(STableComInfo));
-    int32_t totalBytes    = (pChild->tableInfo.numOfColumns + pChild->tableInfo.numOfTags) * sizeof(SSchema);
+    int32_t totalBytes    = (p->tableInfo.numOfColumns + p->tableInfo.numOfTags) * sizeof(SSchema);
     int32_t tableMetaSize =  sizeof(STableMeta)  + totalBytes;
     if (*tableMetaCapacity < tableMetaSize) {
       pChild = realloc(pChild, tableMetaSize); 
       *tableMetaCapacity = (size_t)tableMetaSize;
     }
+
+    pChild->sversion = p->sversion;
+    pChild->tversion = p->tversion;
+    memcpy(&pChild->tableInfo, &p->tableInfo, sizeof(STableComInfo));
     memcpy(pChild->schema, p->schema, totalBytes);
+
     *ppChild = pChild;
     tfree(p);
     return TSDB_CODE_SUCCESS;