fix(query): do not merge rows in last file when no data blocks exist.

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

@@ -2401,6 +2401,19 @@ static int32_t loadNeighborIfOverlap(SFileDataBlockInfo* pBlockInfo, STableBlock
   return code;
 }
 
+static void updateComposedBlockInfo(STsdbReader* pReader, double el, STableBlockScanInfo* pBlockScanInfo) {
+  SSDataBlock* pResBlock = pReader->pResBlock;
+
+  pResBlock->info.id.uid = (pBlockScanInfo != NULL) ? pBlockScanInfo->uid : 0;
+  pResBlock->info.dataLoad = 1;
+  blockDataUpdateTsWindow(pResBlock, pReader->suppInfo.slotId[0]);
+
+  setComposedBlockFlag(pReader, true);
+
+  pReader->cost.composedBlocks += 1;
+  pReader->cost.buildComposedBlockTime += el;
+}
+
 static int32_t buildComposedDataBlock(STsdbReader* pReader) {
   int32_t code = TSDB_CODE_SUCCESS;
 
@@ -2412,6 +2425,7 @@ static int32_t buildComposedDataBlock(STsdbReader* pReader) {
   bool    asc = ASCENDING_TRAVERSE(pReader->order);
   int64_t st = taosGetTimestampUs();
   int32_t step = asc ? 1 : -1;
+  double  el = 0;
 
   STableBlockScanInfo* pBlockScanInfo = NULL;
   if (pBlockInfo != NULL) {
@@ -2473,10 +2487,8 @@ static int32_t buildComposedDataBlock(STsdbReader* pReader) {
       }
     }
 
-    bool hasBlockLData = hasDataInLastBlock(pLastBlockReader);
-
     // no data in last block and block, no need to proceed.
-    if ((hasBlockData == false) && (hasBlockLData == false)) {
+    if (hasBlockData == false) {
       break;
     }
 
@@ -2495,15 +2507,8 @@ static int32_t buildComposedDataBlock(STsdbReader* pReader) {
   }
 
 _end:
-  pResBlock->info.id.uid = (pBlockScanInfo != NULL) ? pBlockScanInfo->uid : 0;
-  pResBlock->info.dataLoad = 1;
-  blockDataUpdateTsWindow(pResBlock, pReader->suppInfo.slotId[0]);
-
-  setComposedBlockFlag(pReader, true);
-  double el = (taosGetTimestampUs() - st) / 1000.0;
-
-  pReader->cost.composedBlocks += 1;
-  pReader->cost.buildComposedBlockTime += el;
+  el = (taosGetTimestampUs() - st) / 1000.0;
+  updateComposedBlockInfo(pReader, el, pBlockScanInfo);
 
   if (pResBlock->info.rows > 0) {
     tsdbDebug("%p uid:%" PRIu64 ", composed data block created, brange:%" PRIu64 "-%" PRIu64
@@ -2748,6 +2753,8 @@ static int32_t doLoadLastBlockSequentially(STsdbReader* pReader) {
     return code;
   }
 
+  SSDataBlock* pResBlock = pReader->pResBlock;
+
   while (1) {
     // load the last data block of current table
     STableBlockScanInfo* pScanInfo = *(STableBlockScanInfo**)pStatus->pTableIter;
@@ -2758,15 +2765,33 @@ static int32_t doLoadLastBlockSequentially(STsdbReader* pReader) {
       if (!hasNexTable) {
         return TSDB_CODE_SUCCESS;
       }
+
       continue;
     }
 
-    code = doBuildDataBlock(pReader);
-    if (code != TSDB_CODE_SUCCESS) {
-      return code;
+    int64_t st = taosGetTimestampUs();
+    while (1) {
+      bool hasBlockLData = hasDataInLastBlock(pLastBlockReader);
+
+      // no data in last block and block, no need to proceed.
+      if (hasBlockLData == false) {
+        break;
+      }
+
+      buildComposedDataBlockImpl(pReader, pScanInfo, &pReader->status.fileBlockData, pLastBlockReader);
+      if (pResBlock->info.rows >= pReader->capacity) {
+        break;
+      }
     }
 
-    if (pReader->pResBlock->info.rows > 0) {
+    double el = (taosGetTimestampUs() - st) / 1000.0;
+    updateComposedBlockInfo(pReader, el, pScanInfo);
+
+    if (pResBlock->info.rows > 0) {
+      tsdbDebug("%p uid:%" PRIu64 ", composed data block created, brange:%" PRIu64 "-%" PRIu64
+                " rows:%d, elapsed time:%.2f ms %s",
+                pReader, pResBlock->info.id.uid, pResBlock->info.window.skey, pResBlock->info.window.ekey,
+                pResBlock->info.rows, el, pReader->idStr);
       return TSDB_CODE_SUCCESS;
     }
 

tests/script/tsim/parser/regressiontest.sim

+system sh/stop_dnodes.sh
+system sh/deploy.sh -n dnode1 -i 1
+system sh/exec.sh -n dnode1 -s start
+sql connect
+
+$dbPrefix = reg_db
+$tb = tb
+$rowNum = 8200
+
+$ts0 = 1537146000000
+$delta = 100
+print ========== reg.sim
+$i = 0
+$db = $dbPrefix . $i
+
+sql drop database if exists $db -x step1
+step1:
+sql create database $db vgroups 1;
+
+sql use $db
+sql create table $tb (ts timestamp, c1 int)
+
+$i = 0
+$ts = $ts0
+
+$x = 0
+while $x < $rowNum
+$xs = $x * $delta
+$ts = $ts0 + $xs
+sql insert into $tb values ( $ts , $x )
+$x = $x + 1
+endw
+
+print ================== restart server to commit data into disk
+system sh/exec.sh -n dnode1 -s stop -x SIGINT
+system sh/exec.sh -n dnode1 -s start
+print ================== server restart completed
+sql connect
+
+sql use $db
+sql delete from $tb where ts=1537146000000
+sql delete from $tb where ts=1537146409500
+
+print =========================> TS-2410
+sql select * from  $tb limit 20 offset 4090
+print $data00
+print $data10
+print $data20
+print $data30
+print $data40
+print $data50
+print $data60
+print $data70
+print $data80
+print $data90
+
+if $data40 != @18-09-17 09:06:49.500@ then
+ return -1
+endi
+
+system sh/exec.sh -n dnode1 -s stop -x SIGINT