2016-06-08 05:36:22 +02:00
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--
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-- PARALLEL
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--
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2016-06-17 14:35:47 +02:00
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create or replace function parallel_restricted(int) returns int as
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$$begin return $1; end$$ language plpgsql parallel restricted;
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2016-06-08 05:36:22 +02:00
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-- Serializable isolation would disable parallel query, so explicitly use an
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-- arbitrary other level.
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begin isolation level repeatable read;
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2016-06-18 06:28:51 +02:00
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-- encourage use of parallel plans
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2016-06-08 05:36:22 +02:00
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set parallel_setup_cost=0;
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set parallel_tuple_cost=0;
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Replace min_parallel_relation_size with two new GUCs.
When min_parallel_relation_size was added, the only supported type
of parallel scan was a parallel sequential scan, but there are
pending patches for parallel index scan, parallel index-only scan,
and parallel bitmap heap scan. Those patches introduce two new
types of complications: first, what's relevant is not really the
total size of the relation but the portion of it that we will scan;
and second, index pages and heap pages shouldn't necessarily be
treated in exactly the same way. Typically, the number of index
pages will be quite small, but that doesn't necessarily mean that
a parallel index scan can't pay off.
Therefore, we introduce min_parallel_table_scan_size, which works
out a degree of parallelism for scans based on the number of table
pages that will be scanned (and which is therefore equivalent to
min_parallel_relation_size for parallel sequential scans) and also
min_parallel_index_scan_size which can be used to work out a degree
of parallelism based on the number of index pages that will be
scanned.
Amit Kapila and Robert Haas
Discussion: http://postgr.es/m/CAA4eK1KowGSYYVpd2qPpaPPA5R90r++QwDFbrRECTE9H_HvpOg@mail.gmail.com
Discussion: http://postgr.es/m/CAA4eK1+TnM4pXQbvn7OXqam+k_HZqb0ROZUMxOiL6DWJYCyYow@mail.gmail.com
2017-02-15 19:37:24 +01:00
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set min_parallel_table_scan_size=0;
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2016-06-16 18:00:55 +02:00
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set max_parallel_workers_per_gather=4;
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2016-06-08 05:36:22 +02:00
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explain (costs off)
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select count(*) from a_star;
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QUERY PLAN
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-----------------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 1
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-> Partial Aggregate
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-> Append
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-> Parallel Seq Scan on a_star
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-> Parallel Seq Scan on b_star
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-> Parallel Seq Scan on c_star
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-> Parallel Seq Scan on d_star
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-> Parallel Seq Scan on e_star
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-> Parallel Seq Scan on f_star
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(11 rows)
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select count(*) from a_star;
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count
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-------
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50
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(1 row)
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2017-11-15 14:17:29 +01:00
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-- test with leader participation disabled
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set parallel_leader_participation = off;
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explain (costs off)
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select count(*) from tenk1 where stringu1 = 'GRAAAA';
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QUERY PLAN
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---------------------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 4
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-> Partial Aggregate
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-> Parallel Seq Scan on tenk1
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Filter: (stringu1 = 'GRAAAA'::name)
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(6 rows)
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select count(*) from tenk1 where stringu1 = 'GRAAAA';
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count
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-------
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15
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(1 row)
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-- test with leader participation disabled, but no workers available (so
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-- the leader will have to run the plan despite the setting)
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set max_parallel_workers = 0;
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explain (costs off)
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select count(*) from tenk1 where stringu1 = 'GRAAAA';
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QUERY PLAN
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---------------------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 4
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-> Partial Aggregate
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-> Parallel Seq Scan on tenk1
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Filter: (stringu1 = 'GRAAAA'::name)
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(6 rows)
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select count(*) from tenk1 where stringu1 = 'GRAAAA';
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count
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-------
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15
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(1 row)
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reset max_parallel_workers;
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reset parallel_leader_participation;
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2016-06-16 18:00:55 +02:00
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-- test that parallel_restricted function doesn't run in worker
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alter table tenk1 set (parallel_workers = 4);
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explain (verbose, costs off)
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select parallel_restricted(unique1) from tenk1
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where stringu1 = 'GRAAAA' order by 1;
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QUERY PLAN
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---------------------------------------------------------
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Sort
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Output: (parallel_restricted(unique1))
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Sort Key: (parallel_restricted(tenk1.unique1))
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-> Gather
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Output: parallel_restricted(unique1)
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Workers Planned: 4
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-> Parallel Seq Scan on public.tenk1
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Output: unique1
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Filter: (tenk1.stringu1 = 'GRAAAA'::name)
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(9 rows)
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2016-06-17 22:25:02 +02:00
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-- test parallel plan when group by expression is in target list.
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explain (costs off)
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select length(stringu1) from tenk1 group by length(stringu1);
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QUERY PLAN
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---------------------------------------------------
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Finalize HashAggregate
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Group Key: (length((stringu1)::text))
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-> Gather
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Workers Planned: 4
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-> Partial HashAggregate
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Group Key: length((stringu1)::text)
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-> Parallel Seq Scan on tenk1
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(7 rows)
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select length(stringu1) from tenk1 group by length(stringu1);
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length
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--------
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6
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(1 row)
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2016-06-18 06:28:51 +02:00
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explain (costs off)
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select stringu1, count(*) from tenk1 group by stringu1 order by stringu1;
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QUERY PLAN
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----------------------------------------------------
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Sort
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Sort Key: stringu1
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-> Finalize HashAggregate
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Group Key: stringu1
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-> Gather
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Workers Planned: 4
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-> Partial HashAggregate
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Group Key: stringu1
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-> Parallel Seq Scan on tenk1
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(9 rows)
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2016-06-17 22:25:02 +02:00
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-- test that parallel plan for aggregates is not selected when
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-- target list contains parallel restricted clause.
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explain (costs off)
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select sum(parallel_restricted(unique1)) from tenk1
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group by(parallel_restricted(unique1));
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2017-02-19 11:23:59 +01:00
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QUERY PLAN
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-------------------------------------------------------------------
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2016-06-17 22:25:02 +02:00
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HashAggregate
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Group Key: parallel_restricted(unique1)
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2017-02-19 11:23:59 +01:00
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-> Gather
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Workers Planned: 4
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-> Parallel Index Only Scan using tenk1_unique1 on tenk1
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(5 rows)
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2016-06-17 22:25:02 +02:00
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2017-10-27 22:22:39 +02:00
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-- test prepared statement
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prepare tenk1_count(integer) As select count((unique1)) from tenk1 where hundred > $1;
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explain (costs off) execute tenk1_count(1);
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QUERY PLAN
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----------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 4
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-> Partial Aggregate
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-> Parallel Seq Scan on tenk1
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Filter: (hundred > 1)
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(6 rows)
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execute tenk1_count(1);
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count
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-------
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9800
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(1 row)
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deallocate tenk1_count;
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2017-02-15 00:09:47 +01:00
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-- test parallel plans for queries containing un-correlated subplans.
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alter table tenk2 set (parallel_workers = 0);
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explain (costs off)
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select count(*) from tenk1 where (two, four) not in
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(select hundred, thousand from tenk2 where thousand > 100);
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QUERY PLAN
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------------------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 4
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-> Partial Aggregate
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-> Parallel Seq Scan on tenk1
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Filter: (NOT (hashed SubPlan 1))
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SubPlan 1
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-> Seq Scan on tenk2
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Filter: (thousand > 100)
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(9 rows)
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select count(*) from tenk1 where (two, four) not in
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(select hundred, thousand from tenk2 where thousand > 100);
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count
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-------
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10000
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(1 row)
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2017-04-18 21:43:56 +02:00
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-- this is not parallel-safe due to use of random() within SubLink's testexpr:
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explain (costs off)
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select * from tenk1 where (unique1 + random())::integer not in
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(select ten from tenk2);
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QUERY PLAN
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------------------------------------
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Seq Scan on tenk1
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Filter: (NOT (hashed SubPlan 1))
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SubPlan 1
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-> Seq Scan on tenk2
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(4 rows)
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2017-02-15 00:09:47 +01:00
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alter table tenk2 reset (parallel_workers);
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2017-02-15 19:53:24 +01:00
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-- test parallel index scans.
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set enable_seqscan to off;
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set enable_bitmapscan to off;
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explain (costs off)
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select count((unique1)) from tenk1 where hundred > 1;
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QUERY PLAN
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--------------------------------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 4
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-> Partial Aggregate
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-> Parallel Index Scan using tenk1_hundred on tenk1
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Index Cond: (hundred > 1)
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(6 rows)
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select count((unique1)) from tenk1 where hundred > 1;
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count
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-------
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9800
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(1 row)
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2017-02-19 11:23:59 +01:00
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-- test parallel index-only scans.
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explain (costs off)
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select count(*) from tenk1 where thousand > 95;
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QUERY PLAN
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--------------------------------------------------------------------------------
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Finalize Aggregate
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-> Gather
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Workers Planned: 4
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-> Partial Aggregate
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-> Parallel Index Only Scan using tenk1_thous_tenthous on tenk1
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Index Cond: (thousand > 95)
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(6 rows)
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select count(*) from tenk1 where thousand > 95;
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count
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-------
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9040
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(1 row)
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2017-08-31 19:15:54 +02:00
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-- test rescan cases too
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set enable_material = false;
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explain (costs off)
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select * from
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(select count(unique1) from tenk1 where hundred > 10) ss
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right join (values (1),(2),(3)) v(x) on true;
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QUERY PLAN
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--------------------------------------------------------------------------
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Nested Loop Left Join
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-> Values Scan on "*VALUES*"
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-> Finalize Aggregate
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-> Gather
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Workers Planned: 4
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-> Partial Aggregate
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-> Parallel Index Scan using tenk1_hundred on tenk1
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Index Cond: (hundred > 10)
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(8 rows)
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select * from
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(select count(unique1) from tenk1 where hundred > 10) ss
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right join (values (1),(2),(3)) v(x) on true;
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count | x
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-------+---
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8900 | 1
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8900 | 2
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8900 | 3
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(3 rows)
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explain (costs off)
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select * from
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(select count(*) from tenk1 where thousand > 99) ss
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right join (values (1),(2),(3)) v(x) on true;
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QUERY PLAN
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--------------------------------------------------------------------------------------
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Nested Loop Left Join
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-> Values Scan on "*VALUES*"
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-> Finalize Aggregate
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-> Gather
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Workers Planned: 4
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-> Partial Aggregate
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-> Parallel Index Only Scan using tenk1_thous_tenthous on tenk1
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Index Cond: (thousand > 99)
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(8 rows)
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select * from
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(select count(*) from tenk1 where thousand > 99) ss
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right join (values (1),(2),(3)) v(x) on true;
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count | x
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-------+---
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9000 | 1
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9000 | 2
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9000 | 3
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(3 rows)
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reset enable_material;
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2017-02-15 19:53:24 +01:00
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reset enable_seqscan;
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reset enable_bitmapscan;
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Support parallel bitmap heap scans.
The index is scanned by a single process, but then all cooperating
processes can iterate jointly over the resulting set of heap blocks.
In the future, we might also want to support using a parallel bitmap
index scan to set up for a parallel bitmap heap scan, but that's a
job for another day.
Dilip Kumar, with some corrections and cosmetic changes by me. The
larger patch set of which this is a part has been reviewed and tested
by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia
Sabih, Haribabu Kommi, Thomas Munro, and me.
Discussion: http://postgr.es/m/CAFiTN-uc4=0WxRGfCzs-xfkMYcSEWUC-Fon6thkJGjkh9i=13A@mail.gmail.com
2017-03-08 18:05:43 +01:00
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-- test parallel bitmap heap scan.
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set enable_seqscan to off;
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set enable_indexscan to off;
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2017-04-06 22:36:54 +02:00
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set enable_hashjoin to off;
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set enable_mergejoin to off;
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set enable_material to off;
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2017-04-06 23:21:39 +02:00
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-- test prefetching, if the platform allows it
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DO $$
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BEGIN
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SET effective_io_concurrency = 50;
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EXCEPTION WHEN invalid_parameter_value THEN
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END $$;
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2017-04-06 22:36:54 +02:00
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set work_mem='64kB'; --set small work mem to force lossy pages
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Support parallel bitmap heap scans.
The index is scanned by a single process, but then all cooperating
processes can iterate jointly over the resulting set of heap blocks.
In the future, we might also want to support using a parallel bitmap
index scan to set up for a parallel bitmap heap scan, but that's a
job for another day.
Dilip Kumar, with some corrections and cosmetic changes by me. The
larger patch set of which this is a part has been reviewed and tested
by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia
Sabih, Haribabu Kommi, Thomas Munro, and me.
Discussion: http://postgr.es/m/CAFiTN-uc4=0WxRGfCzs-xfkMYcSEWUC-Fon6thkJGjkh9i=13A@mail.gmail.com
2017-03-08 18:05:43 +01:00
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explain (costs off)
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2017-04-06 22:36:54 +02:00
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select count(*) from tenk1, tenk2 where tenk1.hundred > 1 and tenk2.thousand=0;
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Support parallel bitmap heap scans.
The index is scanned by a single process, but then all cooperating
processes can iterate jointly over the resulting set of heap blocks.
In the future, we might also want to support using a parallel bitmap
index scan to set up for a parallel bitmap heap scan, but that's a
job for another day.
Dilip Kumar, with some corrections and cosmetic changes by me. The
larger patch set of which this is a part has been reviewed and tested
by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia
Sabih, Haribabu Kommi, Thomas Munro, and me.
Discussion: http://postgr.es/m/CAFiTN-uc4=0WxRGfCzs-xfkMYcSEWUC-Fon6thkJGjkh9i=13A@mail.gmail.com
2017-03-08 18:05:43 +01:00
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QUERY PLAN
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------------------------------------------------------------
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2017-04-06 22:36:54 +02:00
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Aggregate
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-> Nested Loop
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-> Seq Scan on tenk2
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Filter: (thousand = 0)
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-> Gather
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Workers Planned: 4
|
Support parallel bitmap heap scans.
The index is scanned by a single process, but then all cooperating
processes can iterate jointly over the resulting set of heap blocks.
In the future, we might also want to support using a parallel bitmap
index scan to set up for a parallel bitmap heap scan, but that's a
job for another day.
Dilip Kumar, with some corrections and cosmetic changes by me. The
larger patch set of which this is a part has been reviewed and tested
by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia
Sabih, Haribabu Kommi, Thomas Munro, and me.
Discussion: http://postgr.es/m/CAFiTN-uc4=0WxRGfCzs-xfkMYcSEWUC-Fon6thkJGjkh9i=13A@mail.gmail.com
2017-03-08 18:05:43 +01:00
|
|
|
-> Parallel Bitmap Heap Scan on tenk1
|
|
|
|
Recheck Cond: (hundred > 1)
|
|
|
|
-> Bitmap Index Scan on tenk1_hundred
|
|
|
|
Index Cond: (hundred > 1)
|
2017-04-06 22:36:54 +02:00
|
|
|
(10 rows)
|
|
|
|
|
|
|
|
select count(*) from tenk1, tenk2 where tenk1.hundred > 1 and tenk2.thousand=0;
|
|
|
|
count
|
|
|
|
-------
|
|
|
|
98000
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
create table bmscantest (a int, t text);
|
|
|
|
insert into bmscantest select r, 'fooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo' FROM generate_series(1,100000) r;
|
|
|
|
create index i_bmtest ON bmscantest(a);
|
|
|
|
select count(*) from bmscantest where a>1;
|
|
|
|
count
|
|
|
|
-------
|
|
|
|
99999
|
|
|
|
(1 row)
|
Support parallel bitmap heap scans.
The index is scanned by a single process, but then all cooperating
processes can iterate jointly over the resulting set of heap blocks.
In the future, we might also want to support using a parallel bitmap
index scan to set up for a parallel bitmap heap scan, but that's a
job for another day.
Dilip Kumar, with some corrections and cosmetic changes by me. The
larger patch set of which this is a part has been reviewed and tested
by (at least) Andres Freund, Amit Khandekar, Tushar Ahuja, Rafia
Sabih, Haribabu Kommi, Thomas Munro, and me.
Discussion: http://postgr.es/m/CAFiTN-uc4=0WxRGfCzs-xfkMYcSEWUC-Fon6thkJGjkh9i=13A@mail.gmail.com
2017-03-08 18:05:43 +01:00
|
|
|
|
|
|
|
reset enable_seqscan;
|
|
|
|
reset enable_indexscan;
|
2017-04-06 22:36:54 +02:00
|
|
|
reset enable_hashjoin;
|
|
|
|
reset enable_mergejoin;
|
|
|
|
reset enable_material;
|
|
|
|
reset effective_io_concurrency;
|
|
|
|
reset work_mem;
|
|
|
|
drop table bmscantest;
|
2017-03-07 17:49:49 +01:00
|
|
|
-- test parallel merge join path.
|
|
|
|
set enable_hashjoin to off;
|
|
|
|
set enable_nestloop to off;
|
|
|
|
explain (costs off)
|
|
|
|
select count(*) from tenk1, tenk2 where tenk1.unique1 = tenk2.unique1;
|
|
|
|
QUERY PLAN
|
|
|
|
-------------------------------------------------------------------------------
|
|
|
|
Finalize Aggregate
|
|
|
|
-> Gather
|
|
|
|
Workers Planned: 4
|
|
|
|
-> Partial Aggregate
|
|
|
|
-> Merge Join
|
|
|
|
Merge Cond: (tenk1.unique1 = tenk2.unique1)
|
|
|
|
-> Parallel Index Only Scan using tenk1_unique1 on tenk1
|
|
|
|
-> Index Only Scan using tenk2_unique1 on tenk2
|
|
|
|
(8 rows)
|
|
|
|
|
|
|
|
select count(*) from tenk1, tenk2 where tenk1.unique1 = tenk2.unique1;
|
|
|
|
count
|
|
|
|
-------
|
|
|
|
10000
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
reset enable_hashjoin;
|
|
|
|
reset enable_nestloop;
|
2017-08-15 00:21:26 +02:00
|
|
|
-- test gather merge
|
|
|
|
set enable_hashagg = false;
|
2017-03-09 13:40:36 +01:00
|
|
|
explain (costs off)
|
2017-08-15 00:21:26 +02:00
|
|
|
select count(*) from tenk1 group by twenty;
|
2017-03-09 13:40:36 +01:00
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------------
|
|
|
|
Finalize GroupAggregate
|
2017-08-15 00:21:26 +02:00
|
|
|
Group Key: twenty
|
2017-03-09 13:40:36 +01:00
|
|
|
-> Gather Merge
|
|
|
|
Workers Planned: 4
|
|
|
|
-> Partial GroupAggregate
|
2017-08-15 00:21:26 +02:00
|
|
|
Group Key: twenty
|
2017-03-09 13:40:36 +01:00
|
|
|
-> Sort
|
2017-08-15 00:21:26 +02:00
|
|
|
Sort Key: twenty
|
2017-03-09 13:40:36 +01:00
|
|
|
-> Parallel Seq Scan on tenk1
|
|
|
|
(9 rows)
|
|
|
|
|
2017-08-15 00:21:26 +02:00
|
|
|
select count(*) from tenk1 group by twenty;
|
|
|
|
count
|
|
|
|
-------
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
(20 rows)
|
|
|
|
|
2017-11-13 22:33:56 +01:00
|
|
|
--test expressions in targetlist are pushed down for gather merge
|
|
|
|
create or replace function simple_func(var1 integer) returns integer
|
|
|
|
as $$
|
|
|
|
begin
|
|
|
|
return var1 + 10;
|
|
|
|
end;
|
|
|
|
$$ language plpgsql PARALLEL SAFE;
|
|
|
|
explain (costs off, verbose)
|
|
|
|
select ten, simple_func(ten) from tenk1 where ten < 100 order by ten;
|
|
|
|
QUERY PLAN
|
|
|
|
-----------------------------------------------------
|
|
|
|
Gather Merge
|
|
|
|
Output: ten, (simple_func(ten))
|
|
|
|
Workers Planned: 4
|
|
|
|
-> Result
|
|
|
|
Output: ten, simple_func(ten)
|
|
|
|
-> Sort
|
|
|
|
Output: ten
|
|
|
|
Sort Key: tenk1.ten
|
|
|
|
-> Parallel Seq Scan on public.tenk1
|
|
|
|
Output: ten
|
|
|
|
Filter: (tenk1.ten < 100)
|
|
|
|
(11 rows)
|
|
|
|
|
|
|
|
drop function simple_func(integer);
|
2017-11-15 14:17:29 +01:00
|
|
|
-- test gather merge with parallel leader participation disabled
|
|
|
|
set parallel_leader_participation = off;
|
|
|
|
explain (costs off)
|
|
|
|
select count(*) from tenk1 group by twenty;
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------------
|
|
|
|
Finalize GroupAggregate
|
|
|
|
Group Key: twenty
|
|
|
|
-> Gather Merge
|
|
|
|
Workers Planned: 4
|
|
|
|
-> Partial GroupAggregate
|
|
|
|
Group Key: twenty
|
|
|
|
-> Sort
|
|
|
|
Sort Key: twenty
|
|
|
|
-> Parallel Seq Scan on tenk1
|
|
|
|
(9 rows)
|
|
|
|
|
|
|
|
select count(*) from tenk1 group by twenty;
|
|
|
|
count
|
|
|
|
-------
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
500
|
|
|
|
(20 rows)
|
|
|
|
|
|
|
|
reset parallel_leader_participation;
|
2017-08-30 15:59:23 +02:00
|
|
|
--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;
|
2017-08-29 19:12:23 +02:00
|
|
|
reset enable_hashagg;
|
2017-11-14 21:03:55 +01:00
|
|
|
-- check parallelized int8 aggregate (bug #14897)
|
|
|
|
explain (costs off)
|
|
|
|
select avg(unique1::int8) from tenk1;
|
|
|
|
QUERY PLAN
|
|
|
|
-------------------------------------------------------------------------
|
|
|
|
Finalize Aggregate
|
|
|
|
-> Gather
|
|
|
|
Workers Planned: 4
|
|
|
|
-> Partial Aggregate
|
|
|
|
-> Parallel Index Only Scan using tenk1_unique1 on tenk1
|
|
|
|
(5 rows)
|
|
|
|
|
|
|
|
select avg(unique1::int8) from tenk1;
|
|
|
|
avg
|
|
|
|
-----------------------
|
|
|
|
4999.5000000000000000
|
|
|
|
(1 row)
|
|
|
|
|
2017-08-29 19:12:23 +02:00
|
|
|
-- gather merge test with a LIMIT
|
|
|
|
explain (costs off)
|
|
|
|
select fivethous from tenk1 order by fivethous limit 4;
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------
|
|
|
|
Limit
|
|
|
|
-> Gather Merge
|
|
|
|
Workers Planned: 4
|
|
|
|
-> Sort
|
|
|
|
Sort Key: fivethous
|
|
|
|
-> Parallel Seq Scan on tenk1
|
|
|
|
(6 rows)
|
|
|
|
|
|
|
|
select fivethous from tenk1 order by fivethous limit 4;
|
|
|
|
fivethous
|
|
|
|
-----------
|
|
|
|
0
|
|
|
|
0
|
|
|
|
1
|
|
|
|
1
|
|
|
|
(4 rows)
|
|
|
|
|
2017-08-15 00:21:26 +02:00
|
|
|
-- gather merge test with 0 worker
|
|
|
|
set max_parallel_workers = 0;
|
|
|
|
explain (costs off)
|
|
|
|
select string4 from tenk1 order by string4 limit 5;
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------
|
|
|
|
Limit
|
|
|
|
-> Gather Merge
|
|
|
|
Workers Planned: 4
|
|
|
|
-> Sort
|
|
|
|
Sort Key: string4
|
|
|
|
-> Parallel Seq Scan on tenk1
|
|
|
|
(6 rows)
|
|
|
|
|
|
|
|
select string4 from tenk1 order by string4 limit 5;
|
|
|
|
string4
|
|
|
|
---------
|
|
|
|
AAAAxx
|
|
|
|
AAAAxx
|
|
|
|
AAAAxx
|
|
|
|
AAAAxx
|
|
|
|
AAAAxx
|
|
|
|
(5 rows)
|
2017-03-09 13:40:36 +01:00
|
|
|
|
2017-11-15 14:17:29 +01:00
|
|
|
-- gather merge test with 0 workers, with parallel leader
|
|
|
|
-- participation disabled (the leader will have to run the plan
|
|
|
|
-- despite the setting)
|
|
|
|
set parallel_leader_participation = off;
|
|
|
|
explain (costs off)
|
|
|
|
select string4 from tenk1 order by string4 limit 5;
|
|
|
|
QUERY PLAN
|
|
|
|
----------------------------------------------
|
|
|
|
Limit
|
|
|
|
-> Gather Merge
|
|
|
|
Workers Planned: 4
|
|
|
|
-> Sort
|
|
|
|
Sort Key: string4
|
|
|
|
-> Parallel Seq Scan on tenk1
|
|
|
|
(6 rows)
|
|
|
|
|
|
|
|
select string4 from tenk1 order by string4 limit 5;
|
|
|
|
string4
|
|
|
|
---------
|
|
|
|
AAAAxx
|
|
|
|
AAAAxx
|
|
|
|
AAAAxx
|
|
|
|
AAAAxx
|
|
|
|
AAAAxx
|
|
|
|
(5 rows)
|
|
|
|
|
|
|
|
reset parallel_leader_participation;
|
2017-08-15 00:21:26 +02:00
|
|
|
reset max_parallel_workers;
|
2017-08-25 02:42:49 +02:00
|
|
|
SAVEPOINT settings;
|
|
|
|
SET LOCAL force_parallel_mode = 1;
|
2016-06-08 05:36:22 +02:00
|
|
|
explain (costs off)
|
|
|
|
select stringu1::int2 from tenk1 where unique1 = 1;
|
|
|
|
QUERY PLAN
|
|
|
|
-----------------------------------------------
|
|
|
|
Gather
|
|
|
|
Workers Planned: 1
|
|
|
|
Single Copy: true
|
|
|
|
-> Index Scan using tenk1_unique1 on tenk1
|
|
|
|
Index Cond: (unique1 = 1)
|
|
|
|
(5 rows)
|
|
|
|
|
2017-08-25 02:42:49 +02:00
|
|
|
ROLLBACK TO SAVEPOINT settings;
|
|
|
|
-- exercise record typmod remapping between backends
|
|
|
|
CREATE OR REPLACE FUNCTION make_record(n int)
|
|
|
|
RETURNS RECORD LANGUAGE plpgsql PARALLEL SAFE AS
|
|
|
|
$$
|
|
|
|
BEGIN
|
|
|
|
RETURN CASE n
|
|
|
|
WHEN 1 THEN ROW(1)
|
|
|
|
WHEN 2 THEN ROW(1, 2)
|
|
|
|
WHEN 3 THEN ROW(1, 2, 3)
|
|
|
|
WHEN 4 THEN ROW(1, 2, 3, 4)
|
|
|
|
ELSE ROW(1, 2, 3, 4, 5)
|
|
|
|
END;
|
|
|
|
END;
|
|
|
|
$$;
|
|
|
|
SAVEPOINT settings;
|
|
|
|
SET LOCAL force_parallel_mode = 1;
|
|
|
|
SELECT make_record(x) FROM (SELECT generate_series(1, 5) x) ss ORDER BY x;
|
|
|
|
make_record
|
|
|
|
-------------
|
|
|
|
(1)
|
|
|
|
(1,2)
|
|
|
|
(1,2,3)
|
|
|
|
(1,2,3,4)
|
|
|
|
(1,2,3,4,5)
|
|
|
|
(5 rows)
|
|
|
|
|
|
|
|
ROLLBACK TO SAVEPOINT settings;
|
|
|
|
DROP function make_record(n int);
|
2017-10-29 08:28:40 +01:00
|
|
|
-- test the sanity of parallel query after the active role is dropped.
|
|
|
|
drop role if exists regress_parallel_worker;
|
|
|
|
NOTICE: role "regress_parallel_worker" does not exist, skipping
|
|
|
|
create role regress_parallel_worker;
|
|
|
|
set role regress_parallel_worker;
|
|
|
|
reset session authorization;
|
|
|
|
drop role regress_parallel_worker;
|
|
|
|
set force_parallel_mode = 1;
|
|
|
|
select count(*) from tenk1;
|
|
|
|
count
|
|
|
|
-------
|
|
|
|
10000
|
|
|
|
(1 row)
|
|
|
|
|
|
|
|
reset force_parallel_mode;
|
|
|
|
reset role;
|
2017-04-06 22:44:48 +02:00
|
|
|
-- to increase the parallel query test coverage
|
2017-08-25 02:42:49 +02:00
|
|
|
SAVEPOINT settings;
|
|
|
|
SET LOCAL force_parallel_mode = 1;
|
2017-04-06 22:44:48 +02:00
|
|
|
EXPLAIN (analyze, timing off, summary off, costs off) SELECT * FROM tenk1;
|
|
|
|
QUERY PLAN
|
|
|
|
-------------------------------------------------------------
|
|
|
|
Gather (actual rows=10000 loops=1)
|
|
|
|
Workers Planned: 4
|
|
|
|
Workers Launched: 4
|
|
|
|
-> Parallel Seq Scan on tenk1 (actual rows=2000 loops=5)
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(4 rows)
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2017-08-25 02:42:49 +02:00
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ROLLBACK TO SAVEPOINT settings;
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2016-08-22 18:00:00 +02:00
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-- provoke error in worker
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2017-08-25 02:42:49 +02:00
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SAVEPOINT settings;
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SET LOCAL force_parallel_mode = 1;
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2016-08-22 18:00:00 +02:00
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select stringu1::int2 from tenk1 where unique1 = 1;
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ERROR: invalid input syntax for integer: "BAAAAA"
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CONTEXT: parallel worker
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2017-08-25 02:42:49 +02:00
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ROLLBACK TO SAVEPOINT settings;
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2016-06-08 05:36:22 +02:00
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rollback;
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