feat(query): add sample function

source/libs/function/src/builtinsimpl.c

@@ -155,6 +155,7 @@ typedef struct SSampleInfo {
   int32_t samples;
   int32_t totalPoints;
   int32_t numSampled;
+  uint8_t colType;
   int16_t colBytes;
   char *data;
   int64_t *timestamp;
@@ -3063,7 +3064,8 @@ bool sampleFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo *pResultInfo)
   pInfo->samples = pCtx->param[1].param.i;
   pInfo->totalPoints = 0;
   pInfo->numSampled = 0;
-  pInfo->colBytes = ((SColumnInfoData*)pCtx->pOutput)->info.bytes;
+  pInfo->colType = pCtx->resDataInfo.type;
+  pInfo->colBytes = pCtx->resDataInfo.bytes;
   if (pInfo->samples < 1 || pInfo->samples > SAMPLE_MAX_POINTS_NUM) {
     return false;
   }
@@ -3073,22 +3075,20 @@ bool sampleFunctionSetup(SqlFunctionCtx *pCtx, SResultRowEntryInfo *pResultInfo)
   return true;
 }
 
-static void sampleAssignResult(SColumnInfoData *pOutput, SSampleInfo* pInfo,
-                                char *data, TSKEY ts, int32_t index) {
-  assignVal(pInfo->data + index * pInfo->colBytes, data, pOutput->info.bytes, pOutput->info.type);
+static void sampleAssignResult(SSampleInfo* pInfo, char *data, TSKEY ts, int32_t index) {
+  assignVal(pInfo->data + index * pInfo->colBytes, data, pInfo->colBytes, pInfo->colType);
   *(pInfo->timestamp + index) = ts;
 }
 
-static void doReservoirSample(SColumnInfoData *pOutput, SSampleInfo* pInfo,
-                              char *data, TSKEY ts, int32_t index) {
+static void doReservoirSample(SSampleInfo* pInfo, char *data, TSKEY ts, int32_t index) {
   pInfo->totalPoints++;
   if (pInfo->numSampled < pInfo->samples) {
-    sampleAssignResult(pOutput, pInfo, data, ts, pInfo->numSampled);
+    sampleAssignResult(pInfo, data, ts, pInfo->numSampled);
     pInfo->numSampled++;
   } else {
     int32_t j = taosRand() % (pInfo->totalPoints);
     if (j < pInfo->samples) {
-      sampleAssignResult(pOutput, pInfo, data, ts, j);
+      sampleAssignResult(pInfo, data, ts, j);
     }
   }
 }
@@ -3113,7 +3113,7 @@ int32_t sampleFunction(SqlFunctionCtx* pCtx) {
     }
 
     char* data = colDataGetData(pInputCol, i);
-    doReservoirSample(pOutput, pInfo, data, tsList[i], i);
+    doReservoirSample(pInfo, data, tsList[i], i);
   }
 
   return pInfo->numSampled;