Merge pull request #20156 from taosdata/fix/TD-22520

fix(query): fix apply limit error for doMultiwayMerge operator if datablocks belongs to the same group

source/libs/executor/src/sortoperator.c

@@ -672,7 +672,9 @@ SSDataBlock* getMultiwaySortedBlockData(SSortHandle* pHandle, SSDataBlock* pData
     }
 
     bool limitReached = applyLimitOffset(&pInfo->limitInfo, p, pTaskInfo);
-    if (limitReached) {
+    // if limit is reached within a group, do not clear limiInfo otherwise the next block
+    // will be processed.
+    if (newgroup && limitReached) {
       resetLimitInfoForNextGroup(&pInfo->limitInfo);
     }
 

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

@@ -124,6 +124,18 @@ class TDTestCase:
         sql2 = "select count(t1) from (select * from %s.meters)" %dbname
         self.sql_base_check(sql1,sql2)
 
+        # TD-22520
+        tdSql.query("select tbname, ts from %s.meters where ts < '2017-07-14 10:40:00' order by ts asc limit 150;" %dbname)
+        tdSql.checkRows(150)
+
+        tdSql.query("select tbname, ts from %s.meters where ts < '2017-07-14 10:40:00' order by ts asc limit 300;" %dbname)
+        tdSql.checkRows(300)
+
+        tdSql.query("select tbname, ts from %s.meters where ts < '2017-07-14 10:40:00' order by ts desc limit 150;" %dbname)
+        tdSql.checkRows(150)
+
+        tdSql.query("select tbname, ts from %s.meters where ts < '2017-07-14 10:40:00' order by ts desc limit 300;" %dbname)
+        tdSql.checkRows(300)
 
     def sql_base_check(self,sql1,sql2):
         tdSql.query(sql1)