From a2b70c89ca1a5fcf6181d3c777d82e7b83d2de1b Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Thu, 17 Aug 2017 13:49:22 -0400 Subject: [PATCH] Fix ExecReScanGatherMerge. Not surprisingly, since it'd never ever been tested, ExecReScanGatherMerge didn't work. Fix it, and add a regression test case to exercise it. Amit Kapila Discussion: https://postgr.es/m/CAA4eK1JkByysFJNh9M349u_nNjqETuEnY_y1VUc_kJiU0bxtaQ@mail.gmail.com --- src/backend/executor/nodeGatherMerge.c | 1 + src/test/regress/expected/select_parallel.out | 43 +++++++++++++++++++ src/test/regress/sql/select_parallel.sql | 16 +++++++ 3 files changed, 60 insertions(+) diff --git a/src/backend/executor/nodeGatherMerge.c b/src/backend/executor/nodeGatherMerge.c index 9a81e22510..64c62398bb 100644 --- a/src/backend/executor/nodeGatherMerge.c +++ b/src/backend/executor/nodeGatherMerge.c @@ -334,6 +334,7 @@ ExecReScanGatherMerge(GatherMergeState *node) ExecShutdownGatherMergeWorkers(node); node->initialized = false; + node->gm_initialized = false; if (node->pei) ExecParallelReinitialize(node->pei); diff --git a/src/test/regress/expected/select_parallel.out b/src/test/regress/expected/select_parallel.out index 0efb211c97..db31837ede 100644 --- a/src/test/regress/expected/select_parallel.out +++ b/src/test/regress/expected/select_parallel.out @@ -300,6 +300,49 @@ select count(*) from tenk1 group by twenty; 500 (20 rows) +--test rescan behavior of gather merge +set enable_material = false; +explain (costs off) +select * from + (select string4, count(unique2) + from tenk1 group by string4 order by string4) ss + right join (values (1),(2),(3)) v(x) on true; + QUERY PLAN +---------------------------------------------------------- + Nested Loop Left Join + -> Values Scan on "*VALUES*" + -> Finalize GroupAggregate + Group Key: tenk1.string4 + -> Gather Merge + Workers Planned: 4 + -> Partial GroupAggregate + Group Key: tenk1.string4 + -> Sort + Sort Key: tenk1.string4 + -> Parallel Seq Scan on tenk1 +(11 rows) + +select * from + (select string4, count(unique2) + from tenk1 group by string4 order by string4) ss + right join (values (1),(2),(3)) v(x) on true; + string4 | count | x +---------+-------+--- + AAAAxx | 2500 | 1 + HHHHxx | 2500 | 1 + OOOOxx | 2500 | 1 + VVVVxx | 2500 | 1 + AAAAxx | 2500 | 2 + HHHHxx | 2500 | 2 + OOOOxx | 2500 | 2 + VVVVxx | 2500 | 2 + AAAAxx | 2500 | 3 + HHHHxx | 2500 | 3 + OOOOxx | 2500 | 3 + VVVVxx | 2500 | 3 +(12 rows) + +reset enable_material; -- gather merge test with 0 worker set max_parallel_workers = 0; explain (costs off) diff --git a/src/test/regress/sql/select_parallel.sql b/src/test/regress/sql/select_parallel.sql index e717f92e53..33ce61a026 100644 --- a/src/test/regress/sql/select_parallel.sql +++ b/src/test/regress/sql/select_parallel.sql @@ -118,6 +118,22 @@ explain (costs off) select count(*) from tenk1 group by twenty; +--test rescan behavior of gather merge +set enable_material = false; + +explain (costs off) +select * from + (select string4, count(unique2) + from tenk1 group by string4 order by string4) ss + right join (values (1),(2),(3)) v(x) on true; + +select * from + (select string4, count(unique2) + from tenk1 group by string4 order by string4) ss + right join (values (1),(2),(3)) v(x) on true; + +reset enable_material; + -- gather merge test with 0 worker set max_parallel_workers = 0; explain (costs off) -- 2.40.0