feat(query): change config to tsAggAlways and apply code

src/common/inc/tglobal.h

@@ -219,7 +219,7 @@ extern int32_t  cqDebugFlag;
 extern int32_t  debugFlag;
 
 extern int8_t tsClientMerge;
-extern int8_t tsCountAlwaysReturnValue;
+extern int8_t tsAggAlways;
 
 // probe alive connection
 extern int32_t tsProbeSeconds;

src/common/src/tglobal.c

@@ -273,7 +273,7 @@ int32_t  cqDebugFlag = 131;
 int32_t  fsDebugFlag = 135;
 
 int8_t tsClientMerge = 0;
-int8_t tsCountAlwaysReturnValue = 0;
+int8_t tsAggAlways = 0; // Agg function always return value even if zero row 
 
 // probe alive connection
 int32_t tsProbeSeconds     =  5 * 60; // start probe link alive after tsProbeSeconds from starting query
@@ -1691,8 +1691,8 @@ static void doInitGlobalConfig(void) {
   cfg.unitType = TAOS_CFG_UTYPE_NONE;
   taosInitConfigOption(cfg);
 
-  cfg.option = "countAlwaysReturnValue";
-  cfg.ptr = &tsCountAlwaysReturnValue;
+  cfg.option = "aggAlways";
+  cfg.ptr = &tsAggAlways;
   cfg.valType = TAOS_CFG_VTYPE_INT8;
   cfg.cfgType = TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_SHOW;
   cfg.minValue = 0;

src/query/src/qAggMain.c

@@ -30,6 +30,7 @@
 #include "qUdf.h"
 #include "tcompare.h"
 #include "hashfunc.h"
+#include "tglobal.h"
 
 #define GET_INPUT_DATA_LIST(x) ((char *)((x)->pInput))
 #define GET_INPUT_DATA(x, y) (GET_INPUT_DATA_LIST(x) + (y) * (x)->inputBytes)
@@ -936,7 +937,7 @@ static void count_function(SQLFunctionCtx *pCtx) {
     }
   }
 
-  if (numOfElem > 0 || tsCountAlwaysReturnValue) {
+  if (numOfElem > 0 || tsAggAlways) {
     GET_RES_INFO(pCtx)->hasResult = DATA_SET_FLAG;
     *((int64_t *)pCtx->pOutput) += numOfElem;
     pCtx->resultInfo->numOfRes = 1;
@@ -1156,6 +1157,11 @@ static void sum_func_merge(SQLFunctionCtx *pCtx) {
     }
   }
 
+  // support always return value option
+  if(notNullElems == 0 && tsAggAlways) {
+    notNullElems = 1;
+  }
+
   SET_VAL(pCtx, notNullElems, 1);
   SResultRowCellInfo *pResInfo = GET_RES_INFO(pCtx);
 

src/query/src/queryMain.c

@@ -338,6 +338,27 @@ int32_t qRetrieveQueryResultInfo(qinfo_t qinfo, bool* buildRes, void* pRspContex
   return code;
 }
 
+bool qFitAlwaysValue(SQInfo * pQInfo) {
+  // must agg query
+  if (pQInfo->query.simpleAgg)
+    return false;
+  
+  // must not include ts column
+  SSDataBlock* pBlock = pQInfo->runtimeEnv.outputBuf;
+  if (pBlock == NULL || pBlock->pDataBlock == NULL)
+    return false;
+
+  SColumnInfoData* pColInfoData = taosArrayGet(pBlock->pDataBlock, 0);
+  if (pColInfoData == NULL)
+    return false;
+  // must not first column is timestamp  
+  if (pColInfoData->info.type == TSDB_DATA_TYPE_TIMESTAMP)
+    return false;
+
+  // fit ok
+  return true;
+}
+
 int32_t qDumpRetrieveResult(qinfo_t qinfo, SRetrieveTableRsp **pRsp, int32_t *contLen, bool* continueExec) {
   SQInfo *pQInfo = (SQInfo *)qinfo;
   int32_t compLen = 0;
@@ -350,6 +371,11 @@ int32_t qDumpRetrieveResult(qinfo_t qinfo, SRetrieveTableRsp **pRsp, int32_t *co
   SQueryRuntimeEnv* pRuntimeEnv = &pQInfo->runtimeEnv;
 
   int32_t s = GET_NUM_OF_RESULTS(pRuntimeEnv);
+  if (s == 0 && tsAggAlways) {
+    if (qFitAlwaryValue(pQInfo))
+      s = 1;
+  }
+
   size_t size = pQueryAttr->resultRowSize * s;
   size += sizeof(int32_t);
   size += sizeof(STableIdInfo) * taosHashGetSize(pRuntimeEnv->pTableRetrieveTsMap);