tsdb/cache: new separate dataf reader for last file reading

source/dnode/vnode/src/inc/tsdb.h

@@ -720,6 +720,7 @@ typedef struct SCacheRowsReader {
   SSttBlockLoadInfo *pLoadInfo;
   STsdbReadSnap     *pReadSnap;
   SDataFReader      *pDataFReader;
+  SDataFReader      *pDataFReaderLast;
 } SCacheRowsReader;
 
 typedef struct {

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

@@ -951,7 +951,8 @@ typedef struct {
 } CacheNextRowIter;
 
 static int32_t nextRowIterOpen(CacheNextRowIter *pIter, tb_uid_t uid, STsdb *pTsdb, STSchema *pTSchema, tb_uid_t suid,
-                               SSttBlockLoadInfo *pLoadInfo, STsdbReadSnap *pReadSnap, SDataFReader **pDataFReader) {
+                               SSttBlockLoadInfo *pLoadInfo, STsdbReadSnap *pReadSnap, SDataFReader **pDataFReader,
+                               SDataFReader **pDataFReaderLast) {
   int code = 0;
 
   STbData *pMem = NULL;
@@ -1006,7 +1007,7 @@ static int32_t nextRowIterOpen(CacheNextRowIter *pIter, tb_uid_t uid, STsdb *pTs
   pIter->fsLastState.suid = suid;
   pIter->fsLastState.uid = uid;
   pIter->fsLastState.pLoadInfo = pLoadInfo;
-  pIter->fsLastState.pDataFReader = pDataFReader;
+  pIter->fsLastState.pDataFReader = pDataFReaderLast;
 
   pIter->fsState.state = SFSNEXTROW_FS;
   pIter->fsState.pTsdb = pTsdb;
@@ -1148,7 +1149,8 @@ static int32_t mergeLastRow(tb_uid_t uid, STsdb *pTsdb, bool *dup, SArray **ppCo
   TSKEY lastRowTs = TSKEY_MAX;
 
   CacheNextRowIter iter = {0};
-  nextRowIterOpen(&iter, uid, pTsdb, pTSchema, pr->suid, pr->pLoadInfo, pr->pReadSnap, &pr->pDataFReader);
+  nextRowIterOpen(&iter, uid, pTsdb, pTSchema, pr->suid, pr->pLoadInfo, pr->pReadSnap, &pr->pDataFReader,
+                  &pr->pDataFReaderLast);
 
   do {
     TSDBROW *pRow = NULL;
@@ -1272,7 +1274,8 @@ static int32_t mergeLast(tb_uid_t uid, STsdb *pTsdb, SArray **ppLastArray, SCach
   TSKEY lastRowTs = TSKEY_MAX;
 
   CacheNextRowIter iter = {0};
-  nextRowIterOpen(&iter, uid, pTsdb, pTSchema, pr->suid, pr->pLoadInfo, pr->pReadSnap, &pr->pDataFReader);
+  nextRowIterOpen(&iter, uid, pTsdb, pTSchema, pr->suid, pr->pLoadInfo, pr->pReadSnap, &pr->pDataFReader,
+                  &pr->pDataFReaderLast);
 
   do {
     TSDBROW *pRow = NULL;

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

@@ -64,7 +64,7 @@ static void saveOneRow(SArray* pRow, SSDataBlock* pBlock, SCacheRowsReader* pRea
       colDataAppend(pColInfoData, numOfRows, (const char*)pRes[i], false);
     }
 
-    pBlock->info.rows += allNullRow? 0:1;
+    pBlock->info.rows += allNullRow ? 0 : 1;
   } else {
     ASSERT(HASTYPE(pReader->type, CACHESCAN_RETRIEVE_LAST_ROW));
 
@@ -239,6 +239,7 @@ int32_t tsdbRetrieveCacheRows(void* pReader, SSDataBlock* pResBlock, const int32
 
   tsdbTakeReadSnap(pr->pVnode->pTsdb, &pr->pReadSnap, "cache-l");
   pr->pDataFReader = NULL;
+  pr->pDataFReaderLast = NULL;
 
   // retrieve the only one last row of all tables in the uid list.
   if (HASTYPE(pr->type, CACHESCAN_RETRIEVE_TYPE_SINGLE)) {
@@ -334,6 +335,7 @@ int32_t tsdbRetrieveCacheRows(void* pReader, SSDataBlock* pResBlock, const int32
   }
 
 _end:
+  tsdbDataFReaderClose(&pr->pDataFReaderLast);
   tsdbDataFReaderClose(&pr->pDataFReader);
 
   tsdbUntakeReadSnap(pr->pVnode->pTsdb, pr->pReadSnap, "cache-l");