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PG13 has introduced the parallel vacuum functionality in which if the table has two or more indexes (with sizes beyond 512KB and enough number of parallel worker processes), then the vacuum on those indexes can be done in parallel.
27 lines
1.0 KiB
SQL
27 lines
1.0 KiB
SQL
-- This file and its contents are licensed under the Apache License 2.0.
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-- Please see the included NOTICE for copyright information and
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-- LICENSE-APACHE for a copy of the license.
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-- PG13 introduced parallel VACUUM functionality. It gets invoked when a table
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-- has two or more indexes on it. Read up more at
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-- https://www.postgresql.org/docs/13/sql-vacuum.html#PARALLEL
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CREATE TABLE vacuum_test(time timestamp, temp1 float, temp2 int);
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-- create hypertable with chunks
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SELECT create_hypertable('vacuum_test', 'time', chunk_time_interval => 2628000000000);
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-- create additional indexes on the temp columns
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CREATE INDEX vt_temp1 on vacuum_test (temp1);
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CREATE INDEX vt_temp2 on vacuum_test (temp2);
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-- parallel vacuum needs the index size to be larger than 512KB to kick in
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INSERT INTO vacuum_test SELECT TIMESTAMP 'epoch' + (i * INTERVAL '100 second'),
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i, i+1 FROM generate_series(1, 100000) as T(i);
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-- we should see two parallel workers for each chunk
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VACUUM (PARALLEL 3, VERBOSE) vacuum_test;
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DROP TABLE vacuum_test;
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