From 586b3945d1571b2d0ca9320e80fbae147721849b Mon Sep 17 00:00:00 2001
From: Xiaoyu Wang <xiaoyuwang@taosdata.com>
Date: Wed, 19 Apr 2023 13:09:11 +0800
Subject: [PATCH] feat: last queries with tags output can be read from cache

---
 source/dnode/vnode/src/tsdb/tsdbCacheRead.c | 10 ++++------
 source/libs/planner/src/planOptimizer.c     | 12 +++++-------
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
index f537b7d6e8..d6e819d84a 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCacheRead.c
@@ -408,12 +408,10 @@ int32_t tsdbRetrieveCacheRows(void* pReader, SSDataBlock* pResBlock, const int32
         }
       }
 
-      if (0 == i) {
-        if (taosArrayGetSize(pTableUidList) == 0) {
-          taosArrayPush(pTableUidList, &pKeyInfo->uid);
-        } else {
-          taosArraySet(pTableUidList, 0, &pKeyInfo->uid);
-        }
+      if (taosArrayGetSize(pTableUidList) == 0) {
+        taosArrayPush(pTableUidList, &pKeyInfo->uid);
+      } else {
+        taosArraySet(pTableUidList, 0, &pKeyInfo->uid);
       }
 
       tsdbCacheRelease(lruCache, h);
diff --git a/source/libs/planner/src/planOptimizer.c b/source/libs/planner/src/planOptimizer.c
index d3a03b7b75..07ea110d7e 100644
--- a/source/libs/planner/src/planOptimizer.c
+++ b/source/libs/planner/src/planOptimizer.c
@@ -2195,7 +2195,7 @@ static bool lastRowScanOptMayBeOptimized(SLogicNode* pNode) {
   FOREACH(pFunc, ((SAggLogicNode*)pNode)->pAggFuncs) {
     SFunctionNode* pAggFunc = (SFunctionNode*)pFunc;
     if (FUNCTION_TYPE_LAST == pAggFunc->funcType) {
-      if (hasSelectFunc) {
+      if (hasSelectFunc || QUERY_NODE_VALUE == nodeType(nodesListGetNode(pAggFunc->pParameterList, 0))) {
         return false;
       }
       hasLastFunc = true;
@@ -2241,7 +2241,7 @@ static EDealRes lastRowScanOptSetColDataType(SNode* pNode, void* pContext) {
   return DEAL_RES_CONTINUE;
 }
 
-static void lastRowScanOptSetLastTargets(SNodeList* pTargets, SNodeList* pLastCols) {
+static void lastRowScanOptSetLastTargets(SNodeList* pTargets, SNodeList* pLastCols, bool erase) {
   SNode* pTarget = NULL;
   WHERE_EACH(pTarget, pTargets) {
     bool   found = false;
@@ -2253,7 +2253,7 @@ static void lastRowScanOptSetLastTargets(SNodeList* pTargets, SNodeList* pLastCo
         break;
       }
     }
-    if (!found) {
+    if (!found && erase) {
       ERASE_NODE(pTargets);
       continue;
     }
@@ -2286,8 +2286,6 @@ static int32_t lastRowScanOptimize(SOptimizeContext* pCxt, SLogicSubplan* pLogic
         nodesWalkExpr(nodesListGetNode(pFunc->pParameterList, 0), lastRowScanOptSetColDataType, &cxt);
         nodesListErase(pFunc->pParameterList, nodesListGetCell(pFunc->pParameterList, 1));
       }
-    } else if (FUNCTION_TYPE_GROUP_KEY == funcType) {
-      nodesListMakeAppend(&cxt.pLastCols, nodesListGetNode(pFunc->pParameterList, 0));
     }
   }
 
@@ -2296,8 +2294,8 @@ static int32_t lastRowScanOptimize(SOptimizeContext* pCxt, SLogicSubplan* pLogic
   pScan->igLastNull = pAgg->hasLast ? true : false;
   if (NULL != cxt.pLastCols) {
     cxt.doAgg = false;
-    lastRowScanOptSetLastTargets(pScan->pScanCols, cxt.pLastCols);
-    lastRowScanOptSetLastTargets(pScan->node.pTargets, cxt.pLastCols);
+    lastRowScanOptSetLastTargets(pScan->pScanCols, cxt.pLastCols, true);
+    lastRowScanOptSetLastTargets(pScan->node.pTargets, cxt.pLastCols, false);
     nodesClearList(cxt.pLastCols);
   }
   pAgg->hasLastRow = false;
-- 
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