[TD-5797]<feature> support distict multi column

src/common/src/tglobal.c

@@ -84,6 +84,9 @@ int32_t tsMaxNumOfOrderedResults = 100000;
 // 10 ms for sliding time, the value will changed in case of time precision changed
 int32_t tsMinSlidingTime = 10;
 
+// the maxinum number of distict query result   
+int32_t tsMaxNumOfDistinctResults  = 1000 * 10000;
+
 // 1 us for interval time range, changed accordingly
 int32_t tsMinIntervalTime = 1;
 
@@ -541,6 +544,17 @@ static void doInitGlobalConfig(void) {
   cfg.unitType = TAOS_CFG_UTYPE_NONE;
   taosInitConfigOption(cfg);
 
+  cfg.option = "maxNumOfDistinctRes";
+  cfg.ptr = &tsMaxNumOfDistinctResults;
+  cfg.valType = TAOS_CFG_VTYPE_INT32;
+  cfg.cfgType = TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_SHOW | TSDB_CFG_CTYPE_B_CLIENT;
+  cfg.minValue = 10*10000;
+  cfg.maxValue = 10000*10000;
+  cfg.ptrLength = 0;
+  cfg.unitType = TAOS_CFG_UTYPE_NONE;
+  taosInitConfigOption(cfg);
+  
+
   cfg.option = "numOfMnodes";
   cfg.ptr = &tsNumOfMnodes;
   cfg.valType = TAOS_CFG_VTYPE_INT32;

src/query/src/qExecutor.c

@@ -3394,6 +3394,7 @@ void setDefaultOutputBuf(SQueryRuntimeEnv *pRuntimeEnv, SOptrBasicInfo *pInfo, i
   SResultRowInfo* pResultRowInfo = &pInfo->resultRowInfo;
 
   int64_t tid = 0;
+  pRuntimeEnv->keyBuf = realloc(pRuntimeEnv->keyBuf, sizeof(tid) + sizeof(int64_t) + POINTER_BYTES);   
   SResultRow* pRow = doSetResultOutBufByKey(pRuntimeEnv, pResultRowInfo, tid, (char *)&tid, sizeof(tid), true, uid);
 
   for (int32_t i = 0; i < pDataBlock->info.numOfCols; ++i) {
@@ -6725,7 +6726,7 @@ SOperatorInfo* createDistinctOperatorInfo(SQueryRuntimeEnv* pRuntimeEnv, SOperat
   SDistinctOperatorInfo* pInfo = calloc(1, sizeof(SDistinctOperatorInfo));
   pInfo->totalBytes      = 0;
   pInfo->buf             = NULL;
-  pInfo->threshold       = HASH_CAPACITY_LIMIT; // distinct result threshold
+  pInfo->threshold       = tsMaxNumOfDistinctResults; // distinct result threshold
   pInfo->outputCapacity  = 4096;
   pInfo->pDistinctDataInfo = taosArrayInit(numOfOutput, sizeof(SDistinctDataInfo)); 
   pInfo->pSet = taosHashInit(64, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), false, HASH_NO_LOCK);