From 60b85028afe7ca9b609d47f2afafd1d24c2f7bb7 Mon Sep 17 00:00:00 2001
From: Minglei Jin <mljin@taosdata.com>
Date: Wed, 19 Oct 2022 18:53:51 +0800
Subject: [PATCH 1/2] fix: do not copy binary when nData is 0

---
 source/dnode/vnode/src/tsdb/tsdbCache.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/source/dnode/vnode/src/tsdb/tsdbCache.c b/source/dnode/vnode/src/tsdb/tsdbCache.c
index 96504f343a..bb394e8acc 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCache.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCache.c
@@ -61,7 +61,7 @@ static void deleteTableCacheLast(const void *key, size_t keyLen, void *value) {
   int16_t nCol = taosArrayGetSize(pLastArray);
   for (int16_t iCol = 0; iCol < nCol; ++iCol) {
     SLastCol *pLastCol = (SLastCol *)taosArrayGet(pLastArray, iCol);
-    if (IS_VAR_DATA_TYPE(pLastCol->colVal.type)) {
+    if (IS_VAR_DATA_TYPE(pLastCol->colVal.type) && pLastCol->colVal.value.nData > 0) {
       taosMemoryFree(pLastCol->colVal.value.pData);
     }
   }
@@ -1160,7 +1160,7 @@ static int32_t mergeLastRow(tb_uid_t uid, STsdb *pTsdb, bool *dup, SArray **ppCo
         tsdbRowGetColVal(pRow, pTSchema, iCol, pColVal);
 
         SLastCol lastCol = {.ts = lastRowTs, .colVal = *pColVal};
-        if (IS_VAR_DATA_TYPE(pColVal->type)) {
+        if (IS_VAR_DATA_TYPE(pColVal->type) && pColVal->value.nData > 0) {
           lastCol.colVal.value.pData = taosMemoryMalloc(lastCol.colVal.value.nData);
           if (lastCol.colVal.value.pData == NULL) {
             terrno = TSDB_CODE_OUT_OF_MEMORY;
@@ -1202,7 +1202,7 @@ static int32_t mergeLastRow(tb_uid_t uid, STsdb *pTsdb, bool *dup, SArray **ppCo
       tsdbRowGetColVal(pRow, pTSchema, iCol, pColVal);
       if (COL_VAL_IS_NONE(tColVal) && !COL_VAL_IS_NONE(pColVal)) {
         SLastCol lastCol = {.ts = rowTs, .colVal = *pColVal};
-        if (IS_VAR_DATA_TYPE(pColVal->type)) {
+        if (IS_VAR_DATA_TYPE(pColVal->type) && pColVal->value.nData > 0) {
           SLastCol *pLastCol = (SLastCol *)taosArrayGet(pColArray, iCol);
           taosMemoryFree(pLastCol->colVal.value.pData);
 
@@ -1283,7 +1283,7 @@ static int32_t mergeLast(tb_uid_t uid, STsdb *pTsdb, SArray **ppLastArray) {
         tsdbRowGetColVal(pRow, pTSchema, iCol, pColVal);
 
         SLastCol lastCol = {.ts = lastRowTs, .colVal = *pColVal};
-        if (IS_VAR_DATA_TYPE(pColVal->type)) {
+        if (IS_VAR_DATA_TYPE(pColVal->type) && pColVal->value.nData > 0) {
           lastCol.colVal.value.pData = taosMemoryMalloc(lastCol.colVal.value.nData);
           if (lastCol.colVal.value.pData == NULL) {
             terrno = TSDB_CODE_OUT_OF_MEMORY;
@@ -1321,7 +1321,7 @@ static int32_t mergeLast(tb_uid_t uid, STsdb *pTsdb, SArray **ppLastArray) {
       tsdbRowGetColVal(pRow, pTSchema, iCol, pColVal);
       if (!COL_VAL_IS_VALUE(tColVal) && COL_VAL_IS_VALUE(pColVal)) {
         SLastCol lastCol = {.ts = rowTs, .colVal = *pColVal};
-        if (IS_VAR_DATA_TYPE(pColVal->type)) {
+        if (IS_VAR_DATA_TYPE(pColVal->type) && pColVal->value.nData > 0) {
           SLastCol *pLastCol = (SLastCol *)taosArrayGet(pColArray, iCol);
           taosMemoryFree(pLastCol->colVal.value.pData);
 

From b3658f983f4ceecb7f789c49c823039fa2b21217 Mon Sep 17 00:00:00 2001
From: Xiaoyu Wang <xiaoyuwang@taosdata.com>
Date: Thu, 20 Oct 2022 14:35:34 +0800
Subject: [PATCH 2/2] fix: last constant error

---
 source/libs/planner/src/planOptimizer.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/source/libs/planner/src/planOptimizer.c b/source/libs/planner/src/planOptimizer.c
index 2e2e4e6dcf..3171bb531b 100644
--- a/source/libs/planner/src/planOptimizer.c
+++ b/source/libs/planner/src/planOptimizer.c
@@ -2139,20 +2139,28 @@ static int32_t rewriteUniqueOptimize(SOptimizeContext* pCxt, SLogicSubplan* pLog
   return rewriteUniqueOptimizeImpl(pCxt, pLogicSubplan, pIndef);
 }
 
-static EDealRes lastRowScanOptHasTagImpl(SNode* pNode, void* pContext) {
+typedef struct SLastRowScanOptLastParaCkCxt {
+  bool hasTag;
+  bool hasCol;
+} SLastRowScanOptLastParaCkCxt;
+
+static EDealRes lastRowScanOptLastParaCheckImpl(SNode* pNode, void* pContext) {
   if (QUERY_NODE_COLUMN == nodeType(pNode)) {
+    SLastRowScanOptLastParaCkCxt* pCxt = pContext;
     if (COLUMN_TYPE_TAG == ((SColumnNode*)pNode)->colType || COLUMN_TYPE_TBNAME == ((SColumnNode*)pNode)->colType) {
-      *(bool*)pContext = true;
-      return DEAL_RES_END;
+      pCxt->hasTag = true;
+    } else {
+      pCxt->hasCol = true;
     }
+    return DEAL_RES_END;
   }
   return DEAL_RES_CONTINUE;
 }
 
-static bool lastRowScanOptHasTag(SNode* pExpr) {
-  bool hasTag = false;
-  nodesWalkExpr(pExpr, lastRowScanOptHasTagImpl, &hasTag);
-  return hasTag;
+static bool lastRowScanOptLastParaCheck(SNode* pExpr) {
+  SLastRowScanOptLastParaCkCxt cxt = {.hasTag = false, .hasCol = false};
+  nodesWalkExpr(pExpr, lastRowScanOptLastParaCheckImpl, &cxt);
+  return !cxt.hasTag && cxt.hasCol;
 }
 
 static bool hasSuitableCache(int8_t cacheLastMode, bool hasLastRow, bool hasLast) {
@@ -2192,7 +2200,7 @@ static bool lastRowScanOptMayBeOptimized(SLogicNode* pNode) {
   FOREACH(pFunc, ((SAggLogicNode*)pNode)->pAggFuncs) {
     SFunctionNode* pAggFunc = (SFunctionNode*)pFunc;
     if (FUNCTION_TYPE_LAST == pAggFunc->funcType) {
-      if (hasSelectFunc || lastRowScanOptHasTag(nodesListGetNode(pAggFunc->pParameterList, 0))) {
+      if (hasSelectFunc || !lastRowScanOptLastParaCheck(nodesListGetNode(pAggFunc->pParameterList, 0))) {
         return false;
       }
       hasLastFunc = true;