fix: fill operator with desc ts order returned 1 more rows

source/libs/executor/src/filloperator.c

@@ -162,7 +162,6 @@ static void revisedFillStartKey(SFillOperatorInfo* pInfo, SSDataBlock* pBlock, i
     int64_t ekey = pBlock->info.window.ekey;
     if (ekey > pInfo->pFillInfo->start) {
       ASSERT( taosFillNotStarted(pInfo->pFillInfo));
-      taosFillUpdateStartTimestampInfo(pInfo->pFillInfo, ekey);
     } else if (ekey < pInfo->pFillInfo->start) {
       int64_t t = ekey;
       SInterval* pInterval = &pInfo->pFillInfo->interval;
@@ -177,8 +176,9 @@ static void revisedFillStartKey(SFillOperatorInfo* pInfo, SSDataBlock* pBlock, i
       }
 
       // todo time window chosen problem: t or prev value?
-      taosFillUpdateStartTimestampInfo(pInfo->pFillInfo, t);
+      ekey = t;
     }
+    taosFillUpdateStartTimestampInfo(pInfo->pFillInfo, ekey - pInfo->pFillInfo->interval.sliding);
   }
 }
 

tests/system-test/2-query/fill_with_group.py

@@ -130,9 +130,18 @@ class TDTestCase:
             for j in range(0,60):
                 tdSql.checkData(i*1500+j, 1, None)
 
+    def test_fill_with_order_by(self):
+        sql = "select _wstart, _wend, count(ts), sum(c1) from meters where ts > '2018-11-25 00:00:00.000' and ts < '2018-11-26 00:00:00.00' interval(1d) fill(NULL) order by _wstart"
+        tdSql.query(sql)
+        tdSql.checkRows(1)
+        sql = "select _wstart, _wend, count(ts), sum(c1) from meters where ts > '2018-11-25 00:00:00.000' and ts < '2018-11-26 00:00:00.00' interval(1d) fill(NULL) order by _wstart desc"
+        tdSql.query(sql)
+        tdSql.checkRows(1)
+
     def run(self):
         self.prepareTestEnv()
         self.test_partition_by_with_interval_fill_prev_new_group_fill_error()
+        self.test_fill_with_order_by()
 
     def stop(self):
         tdSql.close()