refactor: do some internal refactor.

source/dnode/vnode/src/tsdb/tsdbRead.c

@@ -973,7 +973,7 @@ static void copyNumericCols(const SColData* pData, SFileBlockDumpInfo* pDumpInfo
         int32_t  mid = dumpedRows >> 1u;
         int8_t* pts = (int8_t*)pColData->pData;
         for (int32_t j = 0; j < mid; ++j) {
-          int64_t t = pts[j];
+          int8_t t = pts[j];
           pts[j] = pts[dumpedRows - j - 1];
           pts[dumpedRows - j - 1] = t;
         }
@@ -998,7 +998,7 @@ static void copyNumericCols(const SColData* pData, SFileBlockDumpInfo* pDumpInfo
         int32_t  mid = dumpedRows >> 1u;
         int32_t* pts = (int32_t*)pColData->pData;
         for (int32_t j = 0; j < mid; ++j) {
-          int64_t t = pts[j];
+          int32_t t = pts[j];
           pts[j] = pts[dumpedRows - j - 1];
           pts[dumpedRows - j - 1] = t;
         }

source/libs/function/src/builtinsimpl.c

@@ -3096,6 +3096,8 @@ int32_t lastFunction(SqlFunctionCtx* pCtx) {
   }
 #else
   int64_t* pts = (int64_t*)pInput->pPTS->pData;
+
+  if (IS_VAR_DATA_TYPE(pInputCol->info.type)) {
     for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex; ++i) {
       if (pInputCol->hasNull && colDataIsNull(pInputCol, pInput->totalRows, i, pColAgg)) {
         continue;
@@ -3103,13 +3105,29 @@ int32_t lastFunction(SqlFunctionCtx* pCtx) {
 
       numOfElems++;
 
-    char* data = colDataGetData(pInputCol, i);
+      char* data = colDataGetVarData(pInputCol, i);
+      TSKEY cts = pts[i];
+      if (pResInfo->numOfRes == 0 || pInfo->ts < cts) {
+        doSaveCurrentVal(pCtx, i, cts, type, data);
+        pResInfo->numOfRes = 1;
+      }
+    }
+  } else {
+    for (int32_t i = pInput->startRowIndex; i < pInput->numOfRows + pInput->startRowIndex; ++i) {
+      if (pInputCol->hasNull && colDataIsNull(pInputCol, pInput->totalRows, i, pColAgg)) {
+        continue;
+      }
+
+      numOfElems++;
+
+      char* data = colDataGetNumData(pInputCol, i);
       TSKEY cts = pts[i];
       if (pResInfo->numOfRes == 0 || pInfo->ts < cts) {
         doSaveCurrentVal(pCtx, i, cts, type, data);
         pResInfo->numOfRes = 1;
       }
     }
+  }
 #endif
 
   // save selectivity value for column consisted of all null values
@@ -3266,8 +3284,8 @@ int32_t lastRowFunction(SqlFunctionCtx* pCtx) {
 #if 0
   int32_t blockDataOrder = (startKey <= endKey) ? TSDB_ORDER_ASC : TSDB_ORDER_DESC;
 
-  // the optimized version only function if all tuples in one block are monotonious increasing or descreasing.
-  // this is NOT always works if project operator exists in downstream.
+  // the optimized version only valid if all tuples in one block are monotonious increasing or descreasing.
+  // this assumption is NOT always works if project operator exists in downstream.
   if (blockDataOrder == TSDB_ORDER_ASC) {
     for (int32_t i = pInput->numOfRows + pInput->startRowIndex - 1; i >= pInput->startRowIndex; --i) {
       char* data = colDataGetData(pInputCol, i);