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Commitsfdd965d07and3cd9c3b92tested CREATE INDEX CONCURRENTLY by launching two separate pgbench runs concurrently. This was needed so that only a single client thread would run CREATE INDEX CONCURRENTLY, avoiding deadlock between two CICs. However, there's a better way, which is to use an advisory lock to prevent concurrent CICs. That's better in part because the test code is shorter and more readable, but mostly because it automatically scales things to launch an appropriate number of CICs relative to the number of INSERT transactions. As committed, typically half to three-quarters of the CIC transactions were pointless because the INSERT transactions had already stopped. In passing, remove background_pgbench, which was added to support these tests and isn't needed anymore. We can always put it back if we find a use for it later. Back-patch to v12; older pgbench versions lack the conditional-execution features needed for this method. Tom Lane and Andrey Borodin Discussion: https://postgr.es/m/139687.1635277318@sss.pgh.pa.us
65 lines
1.5 KiB
Perl
65 lines
1.5 KiB
Perl
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# Copyright (c) 2021, PostgreSQL Global Development Group
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# Test CREATE INDEX CONCURRENTLY with concurrent modifications
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use strict;
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use warnings;
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use Config;
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use PostgreSQL::Test::Cluster;
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use PostgreSQL::Test::Utils;
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use Test::More tests => 3;
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my ($node, $result);
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#
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# Test set-up
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#
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$node = PostgreSQL::Test::Cluster->new('CIC_test');
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$node->init;
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$node->append_conf('postgresql.conf', 'lock_timeout = 180000');
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$node->start;
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$node->safe_psql('postgres', q(CREATE EXTENSION amcheck));
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$node->safe_psql('postgres', q(CREATE TABLE tbl(i int)));
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$node->safe_psql('postgres', q(CREATE INDEX idx ON tbl(i)));
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#
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# Stress CIC with pgbench.
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#
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# pgbench might try to launch more than one instance of the CIC
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# transaction concurrently. That would deadlock, so use an advisory
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# lock to ensure only one CIC runs at a time.
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#
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$node->pgbench(
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'--no-vacuum --client=5 --transactions=100',
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0,
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[qr{actually processed}],
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[qr{^$}],
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'concurrent INSERTs and CIC',
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{
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'002_pgbench_concurrent_transaction' => q(
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BEGIN;
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INSERT INTO tbl VALUES(0);
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COMMIT;
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),
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'002_pgbench_concurrent_transaction_savepoints' => q(
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BEGIN;
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SAVEPOINT s1;
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INSERT INTO tbl VALUES(0);
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COMMIT;
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),
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'002_pgbench_concurrent_cic' => q(
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SELECT pg_try_advisory_lock(42)::integer AS gotlock \gset
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\if :gotlock
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DROP INDEX CONCURRENTLY idx;
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CREATE INDEX CONCURRENTLY idx ON tbl(i);
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SELECT bt_index_check('idx',true);
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SELECT pg_advisory_unlock(42);
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\endif
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)
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});
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$node->stop;
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done_testing();
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