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Fix race condition in remove_temp_files_after_crash TAP test

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The TAP test was written so that it was not waiting for the correct SQL
command, but for output from the preceding one.  This resulted in race
conditions, allowing the commands to run in a different order, not block
as expected and so on.  This fixes it by inverting the order of commands
where possible, so that observing the output guarantees the data was
inserted properly, and waiting for a lock to appear in pg_locks.

Discussion: https://postgr.es/m/CAH503wDKdYzyq7U-QJqGn%3DGm6XmoK%2B6_6xTJ-Yn5WSvoHLY1Ww%40mail.gmail.com
This commit is contained in:
Tomas Vondra 2021-03-19 18:12:39 +01:00
parent 27ab1981e7
commit e589c4890b
1 changed files with 42 additions and 2 deletions
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44
src/test/recovery/t/022_crash_temp_files.pl
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@ -79,8 +79,8 @@ my $killme2 = IPC::Run::start(
# Insert one tuple and leave the transaction open
$killme_stdin2 .= q[
BEGIN;
SELECT $$insert-tuple-to-lock-next-insert$$;
INSERT INTO tab_crash (a) VALUES(1);
SELECT $$insert-tuple-to-lock-next-insert$$;
];
pump_until($killme2, \$killme_stdout2, qr/insert-tuple-to-lock-next-insert/m);
$killme_stdout2 = '';
@ -100,6 +100,26 @@ ok(pump_until($killme, \$killme_stdout, qr/in-progress-before-sigkill/m),
$killme_stdout = '';
$killme_stderr = '';
# Wait until the batch insert gets stuck on the lock.
$killme_stdin2 .= q[
DO $c$
DECLARE
c INT;
BEGIN
LOOP
SELECT COUNT(*) INTO c FROM pg_locks WHERE pid = ] . $pid . q[ AND NOT granted;
IF c > 0 THEN
EXIT;
END IF;
END LOOP;
END; $c$;
SELECT $$insert-tuple-lock-waiting$$;
];
pump_until($killme2, \$killme_stdout2, qr/insert-tuple-lock-waiting/m);
$killme_stdout2 = '';
$killme_stderr2 = '';
# Kill with SIGKILL
my $ret = TestLib::system_log('pg_ctl', 'kill', 'KILL', $pid);
is($ret, 0, 'killed process with KILL');
@ -147,8 +167,8 @@ $killme2->run();
# Insert one tuple and leave the transaction open
$killme_stdin2 .= q[
BEGIN;
SELECT $$insert-tuple-to-lock-next-insert$$;
INSERT INTO tab_crash (a) VALUES(1);
SELECT $$insert-tuple-to-lock-next-insert$$;
];
pump_until($killme2, \$killme_stdout2, qr/insert-tuple-to-lock-next-insert/m);
$killme_stdout2 = '';
@ -168,6 +188,26 @@ ok(pump_until($killme, \$killme_stdout, qr/in-progress-before-sigkill/m),
$killme_stdout = '';
$killme_stderr = '';
# Wait until the batch insert gets stuck on the lock.
$killme_stdin2 .= q[
DO $c$
DECLARE
c INT;
BEGIN
LOOP
SELECT COUNT(*) INTO c FROM pg_locks WHERE pid = ] . $pid . q[ AND NOT granted;
IF c > 0 THEN
EXIT;
END IF;
END LOOP;
END; $c$;
SELECT $$insert-tuple-lock-waiting$$;
];
pump_until($killme2, \$killme_stdout2, qr/insert-tuple-lock-waiting/m);
$killme_stdout2 = '';
$killme_stderr2 = '';
# Kill with SIGKILL
$ret = TestLib::system_log('pg_ctl', 'kill', 'KILL', $pid);
is($ret, 0, 'killed process with KILL');