[TD-2378]<enhance>: reduce table meta memory consumption.

src/client/src/tscStream.c

@@ -167,7 +167,9 @@ static void tscProcessStreamQueryCallback(void *param, TAOS_RES *tres, int numOf
              retryDelay);
 
     STableMetaInfo* pTableMetaInfo = tscGetTableMetaInfoFromCmd(&pStream->pSql->cmd, 0, 0);
-    taosCacheRelease(tscMetaCache, (void**)&(pTableMetaInfo->pTableMeta), true);
+
+    char* name = pTableMetaInfo->name;
+    taosHashRemove(tscTableMetaInfo, name, strnlen(name, TSDB_TABLE_FNAME_LEN));
     pTableMetaInfo->vgroupList = tscVgroupInfoClear(pTableMetaInfo->vgroupList);
 
     tscSetRetryTimer(pStream, pStream->pSql, retryDelay);
@@ -269,9 +271,8 @@ static void tscProcessStreamRetrieveResult(void *param, TAOS_RES *res, int numOf
     tscDebug("%p stream:%p, query on:%s, fetch result completed, fetched rows:%" PRId64, pSql, pStream, pTableMetaInfo->name,
              pStream->numOfRes);
 
-    // release the metric/meter meta information reference, so data in cache can be updated
+    tfree(pTableMetaInfo->pTableMeta);
 
-    taosCacheRelease(tscMetaCache, (void**)&(pTableMetaInfo->pTableMeta), false);
     tscFreeSqlResult(pSql);
     tfree(pSql->pSubs);
     pSql->subState.numOfSub = 0;

src/client/src/tscSystem.c

@@ -31,7 +31,6 @@
 #include "tlocale.h"
 
 // global, not configurable
-SCacheObj *tscMetaCache;       // table meta cache
 SHashObj  *tscHashMap;         // hash map to keep the global vgroup info
 SHashObj  *tscTableMetaInfo;       // table meta info
 int     tscObjRef = -1;
@@ -130,9 +129,7 @@ void taos_init_imp(void) {
     taosTmrReset(tscCheckDiskUsage, 10, NULL, tscTmr, &tscCheckDiskUsageTmr);      
   }
 
-  int64_t refreshTime = 10; // 10 seconds by default
-  if (tscMetaCache == NULL) {
-    tscMetaCache = taosCacheInit(TSDB_DATA_TYPE_BINARY, refreshTime, false, NULL, "tableMeta");
+  if (tscTableMetaInfo == NULL) {
     tscObjRef  = taosOpenRef(40960, tscFreeRegisteredSqlObj);
     tscHashMap = taosHashInit(1024, taosGetDefaultHashFunction(TSDB_DATA_TYPE_INT), true, HASH_ENTRY_LOCK);
     tscTableMetaInfo = taosHashInit(1024, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK);
@@ -154,8 +151,8 @@ void taos_init() { pthread_once(&tscinit, taos_init_imp); }
 void taos_cleanup(void) {
   tscDebug("start to cleanup client environment");
 
-  void* m = tscMetaCache;
-  if (m != NULL && atomic_val_compare_exchange_ptr(&tscMetaCache, m, 0) == m) {
+  void* m = tscTableMetaInfo;
+  if (m != NULL && atomic_val_compare_exchange_ptr(&tscTableMetaInfo, m, 0) == m) {
     taosCacheCleanup(m);
   }