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Add tests for recovery deadlock conflicts.

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The recovery conflict tests added in 9f8a050f68d surfaced a bug in the
interaction between buffer pin and deadlock recovery conflicts. To make sure
that the bugfix won't break deadlock conflict detection, add a test for that
scenario.

031_recovery_conflict.pl will later be backpatched, with this included.

Discussion: https://postgr.es/m/20220413002626.udl7lll7f3o7nre7@alap3.anarazel.de
This commit is contained in:
Andres Freund 2022-05-02 17:19:11 -07:00
parent 7307988abd
commit 21e184403b
1 changed files with 79 additions and 7 deletions
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84
src/test/recovery/t/031_recovery_conflict.pl
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@ -4,8 +4,6 @@
# recovery conflict is detected Also, test that statistics in # recovery conflict is detected Also, test that statistics in
# pg_stat_database_conflicts are populated correctly # pg_stat_database_conflicts are populated correctly
# TODO: add a test for deadlock recovery conflicts.
use strict; use strict;
use warnings; use warnings;
use PostgreSQL::Test::Cluster; use PostgreSQL::Test::Cluster;
@ -24,6 +22,9 @@ $node_primary->append_conf(
allow_in_place_tablespaces = on allow_in_place_tablespaces = on
log_temp_files = 0 log_temp_files = 0
# for deadlock test
max_prepared_transactions = 10
# wait some to test the wait paths as well, but not long for obvious reasons # wait some to test the wait paths as well, but not long for obvious reasons
max_standby_streaming_delay = 50ms max_standby_streaming_delay = 50ms
@ -55,9 +56,13 @@ $node_primary->safe_psql('postgres', "CREATE DATABASE $test_db");
# test schema / data # test schema / data
my $table1 = "test_recovery_conflict_table1"; my $table1 = "test_recovery_conflict_table1";
$node_primary->safe_psql($test_db, qq[CREATE TABLE ${table1}(a int, b int);]); my $table2 = "test_recovery_conflict_table2";
$node_primary->safe_psql($test_db, $node_primary->safe_psql(
qq[INSERT INTO $table1 SELECT i % 3, 0 FROM generate_series(1,20) i]); $test_db, qq[
CREATE TABLE ${table1}(a int, b int);
INSERT INTO $table1 SELECT i % 3, 0 FROM generate_series(1,20) i;
CREATE TABLE ${table2}(a int, b int);
]);
my $primary_lsn = $node_primary->lsn('flush'); my $primary_lsn = $node_primary->lsn('flush');
$node_primary->wait_for_catchup($node_standby, 'replay', $primary_lsn); $node_primary->wait_for_catchup($node_standby, 'replay', $primary_lsn);
@ -217,6 +222,67 @@ reconnect_and_clear();
check_conflict_stat("tablespace"); check_conflict_stat("tablespace");
## RECOVERY CONFLICT 5: Deadlock
$sect = "startup deadlock";
$expected_conflicts++;
# Generate a few dead rows, to later be cleaned up by vacuum. Then acquire a
# lock on another relation in a prepared xact, so it's held continuously by
# the startup process. The standby psql will block acquiring that lock while
# holding a pin that vacuum needs, triggering the deadlock.
$node_primary->safe_psql(
$test_db,
qq[
CREATE TABLE $table1(a int, b int);
INSERT INTO $table1 VALUES (1);
BEGIN;
INSERT INTO $table1(a) SELECT generate_series(1, 100) i;
ROLLBACK;
BEGIN;
LOCK TABLE $table2;
PREPARE TRANSACTION 'lock';
INSERT INTO $table1(a) VALUES (170);
SELECT txid_current();
]);
$primary_lsn = $node_primary->lsn('flush');
$node_primary->wait_for_catchup($node_standby, 'replay', $primary_lsn);
$psql_standby{stdin} .= qq[
BEGIN;
-- hold pin
DECLARE $cursor1 CURSOR FOR SELECT a FROM $table1;
FETCH FORWARD FROM $cursor1;
-- wait for lock held by prepared transaction
SELECT * FROM $table2;
];
ok( pump_until(
$psql_standby{run}, $psql_timeout,
\$psql_standby{stdout}, qr/^1$/m,),
"$sect: cursor holding conflicting pin, also waiting for lock, established"
);
# just to make sure we're waiting for lock already
ok( $node_standby->poll_query_until(
'postgres', qq[
SELECT 'waiting' FROM pg_locks WHERE locktype = 'relation' AND NOT granted;
], 'waiting'),
"$sect: lock acquisition is waiting");
# VACUUM will prune away rows, causing a buffer pin conflict, while standby
# psql is waiting on lock
$node_primary->safe_psql($test_db, qq[VACUUM $table1;]);
$primary_lsn = $node_primary->lsn('flush');
$node_primary->wait_for_catchup($node_standby, 'replay', $primary_lsn);
check_conflict_log("User transaction caused buffer deadlock with recovery.");
reconnect_and_clear();
check_conflict_stat("deadlock");
# clean up for next tests
$node_primary->safe_psql($test_db, qq[ROLLBACK PREPARED 'lock';]);
# Check that expected number of conflicts show in pg_stat_database. Needs to # Check that expected number of conflicts show in pg_stat_database. Needs to
# be tested before database is dropped, for obvious reasons. # be tested before database is dropped, for obvious reasons.
is( $node_standby->safe_psql( is( $node_standby->safe_psql(
@ -226,7 +292,7 @@ is( $node_standby->safe_psql(
qq[$expected_conflicts recovery conflicts shown in pg_stat_database]); qq[$expected_conflicts recovery conflicts shown in pg_stat_database]);
## RECOVERY CONFLICT 5: Database conflict ## RECOVERY CONFLICT 6: Database conflict
$sect = "database conflict"; $sect = "database conflict";
$node_primary->safe_psql('postgres', qq[DROP DATABASE $test_db;]); $node_primary->safe_psql('postgres', qq[DROP DATABASE $test_db;]);
@ -259,7 +325,13 @@ sub pump_until_standby
sub reconnect_and_clear sub reconnect_and_clear
{ {
# If psql isn't dead already, tell it to quit as \q, when already dead,
# causes IPC::Run to unhelpfully error out with "ack Broken pipe:".
$psql_standby{run}->pump_nb();
if ($psql_standby{run}->pumpable())
{
$psql_standby{stdin} .= "\\q\n"; $psql_standby{stdin} .= "\\q\n";
}
$psql_standby{run}->finish; $psql_standby{run}->finish;
# restart # restart