test: demonstrate offset not applied correctly with limit pushdown on…

… multiple input streams

datafusion/sqllogictest/test_files/order.slt

@@ -1196,3 +1196,136 @@ physical_plan
 02)--RepartitionExec: partitioning=RoundRobinBatch(2), input_partitions=1
 03)----SortExec: TopK(fetch=1), expr=[a@0 ASC NULLS LAST], preserve_partitioning=[false]
 04)------CsvExec: file_groups={1 group: [[WORKSPACE_ROOT/datafusion/core/tests/data/window_2.csv]]}, projection=[a, b], has_header=true
+
+
+####################
+# Test issue: TBD
+####################
+
+# all results
+query II
+SELECT b, sum(a) FROM ordered_table GROUP BY b order by b desc;
+----
+3 25
+2 25
+1 0
+0 0
+
+# limit only
+query II
+SELECT b, sum(a) FROM ordered_table GROUP BY b order by b desc LIMIT 3;
+----
+3 25
+2 25
+1 0
+
+# offset only
+query II
+SELECT b, sum(a) FROM ordered_table GROUP BY b order by b desc OFFSET 1;
+----
+2 25
+1 0
+0 0
+
+# TODO: fix this to properly apply offset
+# offset + limit
+query II
+SELECT b, sum(a) FROM ordered_table GROUP BY b order by b desc OFFSET 1 LIMIT 2;
+----
+3 25
+2 25
+1 0
+
+# TODO: fix this to not remove the skip=1 during the limit pushdown
+# Applying offset & limit when multiple streams from groupby
+query TT
+EXPLAIN SELECT b, sum(a) FROM ordered_table GROUP BY b order by b desc OFFSET 1 LIMIT 2;
+----
+logical_plan
+01)Limit: skip=1, fetch=2
+02)--Sort: ordered_table.b DESC NULLS FIRST, fetch=3
+03)----Aggregate: groupBy=[[ordered_table.b]], aggr=[[sum(CAST(ordered_table.a AS Int64))]]
+04)------TableScan: ordered_table projection=[a, b]
+physical_plan
+01)SortPreservingMergeExec: [b@0 DESC], fetch=3
+02)--SortExec: TopK(fetch=3), expr=[b@0 DESC], preserve_partitioning=[true]
+03)----AggregateExec: mode=FinalPartitioned, gby=[b@0 as b], aggr=[sum(ordered_table.a)]
+04)------CoalesceBatchesExec: target_batch_size=8192
+05)--------RepartitionExec: partitioning=Hash([b@0], 2), input_partitions=2
+06)----------AggregateExec: mode=Partial, gby=[b@1 as b], aggr=[sum(ordered_table.a)]
+07)------------RepartitionExec: partitioning=RoundRobinBatch(2), input_partitions=1
+08)--------------CsvExec: file_groups={1 group: [[WORKSPACE_ROOT/datafusion/core/tests/data/window_2.csv]]}, projection=[a, b], has_header=true
+
+# TODO: fix this to not remove the skip=4 during the limit pushdown
+# Applying offset & limit when multiple streams from union
+query TT
+explain select * FROM (
+  select c FROM ordered_table
+  UNION ALL
+  select d FROM ordered_table
+) order by 1 desc LIMIT 10 OFFSET 4;
+----
+logical_plan
+01)Limit: skip=4, fetch=10
+02)--Sort: ordered_table.c DESC NULLS FIRST, fetch=14
+03)----Union
+04)------Projection: CAST(ordered_table.c AS Int64) AS c
+05)--------TableScan: ordered_table projection=[c]
+06)------Projection: CAST(ordered_table.d AS Int64) AS c
+07)--------TableScan: ordered_table projection=[d]
+physical_plan
+01)SortPreservingMergeExec: [c@0 DESC], fetch=14
+02)--UnionExec
+03)----SortExec: TopK(fetch=14), expr=[c@0 DESC], preserve_partitioning=[true]
+04)------ProjectionExec: expr=[CAST(c@0 AS Int64) as c]
+05)--------RepartitionExec: partitioning=RoundRobinBatch(2), input_partitions=1
+06)----------CsvExec: file_groups={1 group: [[WORKSPACE_ROOT/datafusion/core/tests/data/window_2.csv]]}, projection=[c], output_ordering=[c@0 ASC NULLS LAST], has_header=true
+07)----SortExec: TopK(fetch=14), expr=[c@0 DESC], preserve_partitioning=[true]
+08)------ProjectionExec: expr=[CAST(d@0 AS Int64) as c]
+09)--------RepartitionExec: partitioning=RoundRobinBatch(2), input_partitions=1
+10)----------CsvExec: file_groups={1 group: [[WORKSPACE_ROOT/datafusion/core/tests/data/window_2.csv]]}, projection=[d], has_header=true
+
+# ApplyingmLIMIT & OFFSET to subquery.
+query III
+select t1.b, c, c2 FROM (
+  select b, c FROM ordered_table ORDER BY b desc, c desc OFFSET 1 LIMIT 4
+) as t1 INNER JOIN (
+  select b, c as c2 FROM ordered_table ORDER BY b desc, d desc OFFSET 1 LIMIT 4
+) as t2
+ON t1.b = t2.b
+ORDER BY t1.b desc, c desc, c2 desc;
+----
+3 98 96
+3 98 89
+3 98 82
+3 98 79
+3 97 96
+3 97 89
+3 97 82
+3 97 79
+3 96 96
+3 96 89
+3 96 82
+3 96 79
+3 95 96
+3 95 89
+3 95 82
+3 95 79
+
+# TODO: fix this does not correctly work.
+# Apply OFFSET & LIMIT to both parent and child (subquery).
+query III
+select t1.b, c, c2 FROM (
+  select b, c FROM ordered_table ORDER BY b desc, c desc OFFSET 1 LIMIT 4
+) as t1 INNER JOIN (
+  select b, c as c2 FROM ordered_table ORDER BY b desc, d desc OFFSET 1 LIMIT 4
+) as t2
+ON t1.b = t2.b
+ORDER BY t1.b desc, c desc, c2 desc
+OFFSET 3 LIMIT 2;
+----
+3 99 96
+3 99 89
+3 99 87
+3 99 82
+3 99 79