From 580b2e587b65833b4bb5e37e4a09fa281b5a6086 Mon Sep 17 00:00:00 2001
From: slzhou <shenglian_zhou@163.com>
Date: Sat, 6 Aug 2022 14:29:12 +0800
Subject: [PATCH] fix: set selectivity value for the null group

---
 source/libs/function/src/builtinsimpl.c | 43 ++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 4 deletions(-)

diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c
index 7fd48519a3..e3e98a6895 100644
--- a/source/libs/function/src/builtinsimpl.c
+++ b/source/libs/function/src/builtinsimpl.c
@@ -64,6 +64,9 @@ typedef struct SMinmaxResInfo {
   bool      assign;  // assign the first value or not
   int64_t   v;
   STuplePos tuplePos;
+
+  STuplePos nullTuplePos;
+  bool      nullTupleSaved;
 } SMinmaxResInfo;
 
 typedef struct STopBotResItem {
@@ -75,6 +78,10 @@ typedef struct STopBotResItem {
 typedef struct STopBotRes {
   int32_t         maxSize;
   int16_t         type;
+
+  STuplePos       nullTuplePos;
+  bool            nullTupleSaved;
+
   STopBotResItem* pItems;
 } STopBotRes;
 
@@ -221,6 +228,10 @@ typedef struct SSampleInfo {
   int32_t    numSampled;
   uint8_t    colType;
   int16_t    colBytes;
+
+  STuplePos  nullTuplePos;
+  bool       nullTupleSaved;
+
   char*      data;
   STuplePos* tuplePos;
 } SSampleInfo;
@@ -1134,6 +1145,9 @@ bool minmaxFunctionSetup(SqlFunctionCtx* pCtx, SResultRowEntryInfo* pResultInfo)
   SMinmaxResInfo* buf = GET_ROWCELL_INTERBUF(pResultInfo);
   buf->assign = false;
   buf->tuplePos.pageId = -1;
+
+  buf->nullTupleSaved = false;
+  buf->nullTuplePos.pageId = -1;
   return true;
 }
 
@@ -1575,6 +1589,10 @@ int32_t doMinMaxHelper(SqlFunctionCtx* pCtx, int32_t isMinFunc) {
   }
 
 _min_max_over:
+  if (numOfElems == 0 && pCtx->subsidiaries.num > 0 && !pBuf->nullTupleSaved ) {
+    doSaveTupleData(pCtx, pInput->startRowIndex, pCtx->pSrcBlock, &pBuf->nullTuplePos);
+    pBuf->nullTupleSaved = true;
+  }
   return numOfElems;
 }
 
@@ -1615,7 +1633,7 @@ int32_t minmaxFunctionFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock) {
   if (pEntryInfo->numOfRes > 0) {
     setSelectivityValue(pCtx, pBlock, &pRes->tuplePos, currentRow);
   } else {
-    setNullSelectivityValue(pCtx, pBlock, currentRow);
+    setSelectivityValue(pCtx, pBlock, &pRes->nullTuplePos, currentRow);
   }
 
   return pEntryInfo->numOfRes;
@@ -3366,6 +3384,8 @@ bool topBotFunctionSetup(SqlFunctionCtx* pCtx, SResultRowEntryInfo* pResInfo) {
 
   pRes->maxSize = pCtx->param[1].param.i;
 
+  pRes->nullTupleSaved = false;
+  pRes->nullTuplePos.pageId = -1;
   return true;
 }
 
@@ -3403,6 +3423,10 @@ int32_t topFunction(SqlFunctionCtx* pCtx) {
     doAddIntoResult(pCtx, data, i, pCtx->pSrcBlock, pRes->type, pInput->uid, pResInfo, true);
   }
 
+  if (numOfElems == 0 && pCtx->subsidiaries.num > 0 && !pRes->nullTupleSaved) {
+    doSaveTupleData(pCtx, pInput->startRowIndex, pCtx->pSrcBlock, &pRes->nullTuplePos);
+    pRes->nullTupleSaved = true;
+  }
   return TSDB_CODE_SUCCESS;
 }
 
@@ -3427,6 +3451,11 @@ int32_t bottomFunction(SqlFunctionCtx* pCtx) {
     doAddIntoResult(pCtx, data, i, pCtx->pSrcBlock, pRes->type, pInput->uid, pResInfo, false);
   }
 
+  if (numOfElems == 0 && pCtx->subsidiaries.num > 0 && !pRes->nullTupleSaved) {
+    doSaveTupleData(pCtx, pInput->startRowIndex, pCtx->pSrcBlock, &pRes->nullTuplePos);
+    pRes->nullTupleSaved = true;
+  }
+
   return TSDB_CODE_SUCCESS;
 }
 
@@ -3627,7 +3656,7 @@ int32_t topBotFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock) {
   int32_t currentRow = pBlock->info.rows;
   if (pEntryInfo->numOfRes <= 0) {
     colDataAppendNULL(pCol, currentRow);
-    setNullSelectivityValue(pCtx, pBlock, currentRow);
+    setSelectivityValue(pCtx, pBlock, &pRes->nullTuplePos, currentRow);
     return pEntryInfo->numOfRes;
   }
   for (int32_t i = 0; i < pEntryInfo->numOfRes; ++i) {
@@ -4902,7 +4931,8 @@ bool sampleFunctionSetup(SqlFunctionCtx* pCtx, SResultRowEntryInfo* pResultInfo)
   pInfo->numSampled = 0;
   pInfo->colType = pCtx->resDataInfo.type;
   pInfo->colBytes = pCtx->resDataInfo.bytes;
-
+  pInfo->nullTuplePos.pageId = -1;
+  pInfo->nullTupleSaved = false;
   pInfo->data = (char*)pInfo + sizeof(SSampleInfo);
   pInfo->tuplePos = (STuplePos*)((char*)pInfo + sizeof(SSampleInfo) + pInfo->samples * pInfo->colBytes);
 
@@ -4948,6 +4978,11 @@ int32_t sampleFunction(SqlFunctionCtx* pCtx) {
     doReservoirSample(pCtx, pInfo, data, i);
   }
 
+  if (pInfo->numSampled == 0 && pCtx->subsidiaries.num > 0 && !pInfo->nullTupleSaved) {
+    doSaveTupleData(pCtx, pInput->startRowIndex, pCtx->pSrcBlock, &pInfo->nullTuplePos);
+    pInfo->nullTupleSaved = true;
+  }
+
   SET_VAL(pResInfo, pInfo->numSampled, pInfo->numSampled);
   return TSDB_CODE_SUCCESS;
 }
@@ -4964,7 +4999,7 @@ int32_t sampleFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock) {
   int32_t currentRow = pBlock->info.rows;
   if (pInfo->numSampled == 0) {
     colDataAppendNULL(pCol, currentRow);
-    setNullSelectivityValue(pCtx, pBlock, currentRow);
+    setSelectivityValue(pCtx, pBlock, &pInfo->nullTuplePos, currentRow);
     return pInfo->numSampled;
   }
   for (int32_t i = 0; i < pInfo->numSampled; ++i) {
-- 
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