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9e7ccd9ef6
Pass CURSOR_OPT_PARALLEL_OK to pg_plan_query() so that parallel plans
are considered when running the underlying SELECT query. This wasn't
done in commit e9baa5e9, which did this for CREATE MATERIALIZED VIEW,
because it wasn't yet known to be safe.
Since REFRESH always inserts into a freshly created table before later
merging or swapping the data into place with separate operations, we can
enable such plans here too.
Author: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Hou, Zhijie <houzj.fnst@cn.fujitsu.com>
Reviewed-by: Luc Vlaming <luc@swarm64.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/CALj2ACXg-4hNKJC6nFnepRHYT4t5jJVstYvri%2BtKQHy7ydcr8A%40mail.gmail.com
81 lines
2.8 KiB
Plaintext
81 lines
2.8 KiB
Plaintext
--
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-- PARALLEL
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--
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begin;
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-- encourage use of parallel plans
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set parallel_setup_cost=0;
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set parallel_tuple_cost=0;
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set min_parallel_table_scan_size=0;
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set max_parallel_workers_per_gather=4;
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--
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-- Test write operations that has an underlying query that is eligible
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-- for parallel plans
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--
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explain (costs off) create table parallel_write as
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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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create table parallel_write as
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select length(stringu1) from tenk1 group by length(stringu1);
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drop table parallel_write;
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explain (costs off) select length(stringu1) into parallel_write
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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) into parallel_write
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from tenk1 group by length(stringu1);
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drop table parallel_write;
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explain (costs off) create materialized view parallel_mat_view as
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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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create materialized view parallel_mat_view as
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select length(stringu1) from tenk1 group by length(stringu1);
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create unique index on parallel_mat_view(length);
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refresh materialized view parallel_mat_view;
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refresh materialized view concurrently parallel_mat_view;
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drop materialized view parallel_mat_view;
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prepare prep_stmt as select length(stringu1) from tenk1 group by length(stringu1);
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explain (costs off) create table parallel_write as execute prep_stmt;
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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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create table parallel_write as execute prep_stmt;
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drop table parallel_write;
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rollback;
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