Test instrumentation of Hash nodes with parallel query.

Commit 8526bcb2df76d5171b4f4d6dc7a97560a73a5eff fixed bugs related
to both Sort and Hash, but only added a test case for Sort.  This
adds a test case for Hash to match.

Thomas Munro

Discussion: http://postgr.es/m/CAEepm=2-LRnfwUBZDqQt+XAcd0af_ykNyyVvP3h1uB1AQ=e-eA@mail.gmail.com

2 files changed, 166 insertions, 0 deletions

diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 001d96dc2d8..9d3abf0ed05 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -6188,6 +6188,112 @@ $$);
 (1 row)
 
 rollback to settings;
+-- Exercise rescans.  We'll turn off parallel_leader_participation so
+-- that we can check that instrumentation comes back correctly.
+create table foo as select generate_series(1, 3) as id, 'xxxxx'::text as t;
+alter table foo set (parallel_workers = 0);
+create table bar as select generate_series(1, 5000) as id, 'xxxxx'::text as t;
+alter table bar set (parallel_workers = 2);
+-- multi-batch with rescan, parallel-oblivious
+savepoint settings;
+set parallel_leader_participation = off;
+set min_parallel_table_scan_size = 0;
+set parallel_setup_cost = 0;
+set parallel_tuple_cost = 0;
+set max_parallel_workers_per_gather = 2;
+set enable_material = off;
+set enable_mergejoin = off;
+set work_mem = '64kB';
+explain (costs off)
+  select count(*) from foo
+    left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+    on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+                                QUERY PLAN                                
+--------------------------------------------------------------------------
+ Aggregate
+   ->  Nested Loop Left Join
+         Join Filter: ((foo.id < (b1.id + 1)) AND (foo.id > (b1.id - 1)))
+         ->  Seq Scan on foo
+         ->  Gather
+               Workers Planned: 2
+               ->  Hash Join
+                     Hash Cond: (b1.id = b2.id)
+                     ->  Parallel Seq Scan on bar b1
+                     ->  Hash
+                           ->  Seq Scan on bar b2
+(11 rows)
+
+select count(*) from foo
+  left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+  on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+ count 
+-------
+     3
+(1 row)
+
+select final > 1 as multibatch
+  from hash_join_batches(
+$$
+  select count(*) from foo
+    left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+    on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+$$);
+ multibatch 
+------------
+ t
+(1 row)
+
+rollback to settings;
+-- single-batch with rescan, parallel-oblivious
+savepoint settings;
+set parallel_leader_participation = off;
+set min_parallel_table_scan_size = 0;
+set parallel_setup_cost = 0;
+set parallel_tuple_cost = 0;
+set max_parallel_workers_per_gather = 2;
+set enable_material = off;
+set enable_mergejoin = off;
+set work_mem = '4MB';
+explain (costs off)
+  select count(*) from foo
+    left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+    on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+                                QUERY PLAN                                
+--------------------------------------------------------------------------
+ Aggregate
+   ->  Nested Loop Left Join
+         Join Filter: ((foo.id < (b1.id + 1)) AND (foo.id > (b1.id - 1)))
+         ->  Seq Scan on foo
+         ->  Gather
+               Workers Planned: 2
+               ->  Hash Join
+                     Hash Cond: (b1.id = b2.id)
+                     ->  Parallel Seq Scan on bar b1
+                     ->  Hash
+                           ->  Seq Scan on bar b2
+(11 rows)
+
+select count(*) from foo
+  left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+  on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+ count 
+-------
+     3
+(1 row)
+
+select final > 1 as multibatch
+  from hash_join_batches(
+$$
+  select count(*) from foo
+    left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+    on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+$$);
+ multibatch 
+------------
+ f
+(1 row)
+
+rollback to settings;
 -- A full outer join where every record is matched.
 -- non-parallel
 savepoint settings;
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index 882601b3388..0e933e00d54 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -2170,6 +2170,66 @@ $$
 $$);
 rollback to settings;
 
+-- Exercise rescans.  We'll turn off parallel_leader_participation so
+-- that we can check that instrumentation comes back correctly.
+
+create table foo as select generate_series(1, 3) as id, 'xxxxx'::text as t;
+alter table foo set (parallel_workers = 0);
+create table bar as select generate_series(1, 5000) as id, 'xxxxx'::text as t;
+alter table bar set (parallel_workers = 2);
+
+-- multi-batch with rescan, parallel-oblivious
+savepoint settings;
+set parallel_leader_participation = off;
+set min_parallel_table_scan_size = 0;
+set parallel_setup_cost = 0;
+set parallel_tuple_cost = 0;
+set max_parallel_workers_per_gather = 2;
+set enable_material = off;
+set enable_mergejoin = off;
+set work_mem = '64kB';
+explain (costs off)
+  select count(*) from foo
+    left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+    on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+select count(*) from foo
+  left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+  on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+select final > 1 as multibatch
+  from hash_join_batches(
+$$
+  select count(*) from foo
+    left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+    on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+$$);
+rollback to settings;
+
+-- single-batch with rescan, parallel-oblivious
+savepoint settings;
+set parallel_leader_participation = off;
+set min_parallel_table_scan_size = 0;
+set parallel_setup_cost = 0;
+set parallel_tuple_cost = 0;
+set max_parallel_workers_per_gather = 2;
+set enable_material = off;
+set enable_mergejoin = off;
+set work_mem = '4MB';
+explain (costs off)
+  select count(*) from foo
+    left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+    on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+select count(*) from foo
+  left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+  on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+select final > 1 as multibatch
+  from hash_join_batches(
+$$
+  select count(*) from foo
+    left join (select b1.id, b1.t from bar b1 join bar b2 using (id)) ss
+    on foo.id < ss.id + 1 and foo.id > ss.id - 1;
+$$);
+rollback to settings;
+
 -- A full outer join where every record is matched.
 
 -- non-parallel