From: Jeff Davis <pgsql@j-davis.com>
To: pgsql-bugs@postgresql.org
Subject: Query stuck with wait event IPC / ParallelFinish
Date: Mon, 04 Mar 2024 20:12:28 -0800
Message-ID: <0f64b4c7fc200890f2055ce4d6650e9c2191fac2.camel@j-davis.com> (raw)
If the attached test patch is applied (no code changes) to master, and
the "amcheck" target is run with debug_parallel_query = regress, I see
the following stuck query:
# select
application_name,
now() - state_change AS duration,
wait_event_type,
wait_event,
state,
query
from pg_stat_activity
where pid<>pg_backend_pid() and backend_type='client backend';
application_name | 004_verify_nbtree_unique.pl
duration | 00:12:29.456255
wait_event_type | IPC
wait_event | ParallelFinish
state | active
query | DELETE FROM bttest_unique3 WHERE 380 <= i
AND i <= 420;
I found this while fixing a parallel query problem with 2af07e2f74, but
the problem can be observed on an earlier version of master as well
(2c29e7fc95) so it's unrelated to my change.
I haven't investigated much, but I don't see an explanation other than
a bug. It reproduces on my local machine consistently.
Regards,
Jeff Davis
Attachments:v1-0001-IPC-ParallelFinish-not-finishing.patch (text/x-patch, 5.7K) download
From eea9bdc454d803c21c2c475eaeb2aa7521332337 Mon Sep 17 00:00:00 2001
From: Jeff Davis <jeff@j-davis.com>
Date: Mon, 4 Mar 2024 19:44:47 -0800
Subject: [PATCH v1] IPC ParallelFinish not finishing
---
contrib/amcheck/t/004_verify_nbtree_unique.pl | 33 +++++++++++--------
1 file changed, 20 insertions(+), 13 deletions(-)
diff --git a/contrib/amcheck/t/004_verify_nbtree_unique.pl b/contrib/amcheck/t/004_verify_nbtree_unique.plindex 3f474a158a..4b704e6815 100644--- a/contrib/amcheck/t/004_verify_nbtree_unique.pl+++ b/contrib/amcheck/t/004_verify_nbtree_unique.pl@@ -20,8 +20,11 @@ $node->safe_psql(
'postgres', q(
CREATE EXTENSION amcheck;
+ CREATE SCHEMA test_amcheck;+ SET search_path = test_amcheck;+
CREATE FUNCTION ok_cmp (int4, int4)
- RETURNS int LANGUAGE sql AS+ RETURNS int LANGUAGE sql SET search_path = test_amcheck AS
$$
SELECT
CASE WHEN $1 < $2 THEN -1
@@ -34,7 +37,7 @@ $node->safe_psql(
--- Check 1: uniqueness violation.
---
CREATE FUNCTION ok_cmp1 (int4, int4)
- RETURNS int LANGUAGE sql AS+ RETURNS int LANGUAGE sql SET search_path = test_amcheck AS
$$
SELECT ok_cmp($1, $2);
$$;
@@ -43,7 +46,7 @@ $node->safe_psql(
--- Make values 768 and 769 look equal.
---
CREATE FUNCTION bad_cmp1 (int4, int4)
- RETURNS int LANGUAGE sql AS+ RETURNS int LANGUAGE sql SET search_path = test_amcheck AS
$$
SELECT
CASE WHEN ($1 = 768 AND $2 = 769) OR
@@ -56,13 +59,13 @@ $node->safe_psql(
--- Check 2: uniqueness violation without deduplication.
---
CREATE FUNCTION ok_cmp2 (int4, int4)
- RETURNS int LANGUAGE sql AS+ RETURNS int LANGUAGE sql SET search_path = test_amcheck AS
$$
SELECT ok_cmp($1, $2);
$$;
CREATE FUNCTION bad_cmp2 (int4, int4)
- RETURNS int LANGUAGE sql AS+ RETURNS int LANGUAGE sql SET search_path = test_amcheck AS
$$
SELECT
CASE WHEN $1 = $2 AND $1 = 400 THEN -1
@@ -74,13 +77,13 @@ $node->safe_psql(
--- Check 3: uniqueness violation with deduplication.
---
CREATE FUNCTION ok_cmp3 (int4, int4)
- RETURNS int LANGUAGE sql AS+ RETURNS int LANGUAGE sql SET search_path = test_amcheck AS
$$
SELECT ok_cmp($1, $2);
$$;
CREATE FUNCTION bad_cmp3 (int4, int4)
- RETURNS int LANGUAGE sql AS+ RETURNS int LANGUAGE sql SET search_path = test_amcheck AS
$$
SELECT bad_cmp2($1, $2);
$$;
@@ -142,7 +145,7 @@ my ($result, $stdout, $stderr);
# We have not yet broken the index, so we should get no corruption
$result = $node->safe_psql(
'postgres', q(
- SELECT bt_index_check('bttest_unique_idx1', true, true);+ SELECT bt_index_check('test_amcheck.bttest_unique_idx1', true, true);
));
is($result, '', 'run amcheck on non-broken bttest_unique_idx1');
@@ -150,6 +153,7 @@ is($result, '', 'run amcheck on non-broken bttest_unique_idx1');
# values to be equal.
$node->safe_psql(
'postgres', q(
+ SET search_path = test_amcheck;
UPDATE pg_catalog.pg_amproc SET
amproc = 'bad_cmp1'::regproc
WHERE amproc = 'ok_cmp1'::regproc;
@@ -157,7 +161,7 @@ $node->safe_psql(
($result, $stdout, $stderr) = $node->psql(
'postgres', q(
- SELECT bt_index_check('bttest_unique_idx1', true, true);+ SELECT bt_index_check('test_amcheck.bttest_unique_idx1', true, true);
));
ok( $stderr =~ /index uniqueness is violated for index "bttest_unique_idx1"/,
'detected uniqueness violation for index "bttest_unique_idx1"');
@@ -175,13 +179,14 @@ ok( $stderr =~ /index uniqueness is violated for index "bttest_unique_idx1"/,
# but no uniqueness violation.
($result, $stdout, $stderr) = $node->psql(
'postgres', q(
- SELECT bt_index_check('bttest_unique_idx2', true, true);+ SELECT bt_index_check('test_amcheck.bttest_unique_idx2', true, true);
));
ok( $stderr =~ /item order invariant violated for index "bttest_unique_idx2"/,
'detected item order invariant violation for index "bttest_unique_idx2"');
$node->safe_psql(
'postgres', q(
+ SET search_path = test_amcheck;
UPDATE pg_catalog.pg_amproc SET
amproc = 'ok_cmp2'::regproc
WHERE amproc = 'bad_cmp2'::regproc;
@@ -189,7 +194,7 @@ $node->safe_psql(
($result, $stdout, $stderr) = $node->psql(
'postgres', q(
- SELECT bt_index_check('bttest_unique_idx2', true, true);+ SELECT bt_index_check('test_amcheck.bttest_unique_idx2', true, true);
));
ok( $stderr =~ /index uniqueness is violated for index "bttest_unique_idx2"/,
'detected uniqueness violation for index "bttest_unique_idx2"');
@@ -206,7 +211,7 @@ ok( $stderr =~ /index uniqueness is violated for index "bttest_unique_idx2"/,
# but no uniqueness violation.
($result, $stdout, $stderr) = $node->psql(
'postgres', q(
- SELECT bt_index_check('bttest_unique_idx3', true, true);+ SELECT bt_index_check('test_amcheck.bttest_unique_idx3', true, true);
));
ok( $stderr =~ /item order invariant violated for index "bttest_unique_idx3"/,
'detected item order invariant violation for index "bttest_unique_idx3"');
@@ -215,6 +220,7 @@ ok( $stderr =~ /item order invariant violated for index "bttest_unique_idx3"/,
# with different visibility.
$node->safe_psql(
'postgres', q(
+ SET search_path = test_amcheck;
DELETE FROM bttest_unique3 WHERE 380 <= i AND i <= 420;
INSERT INTO bttest_unique3 (SELECT * FROM generate_series(380, 420));
INSERT INTO bttest_unique3 VALUES (400);
@@ -228,6 +234,7 @@ $node->safe_psql(
$node->safe_psql(
'postgres', q(
+ SET search_path = test_amcheck;
UPDATE pg_catalog.pg_amproc SET
amproc = 'ok_cmp3'::regproc
WHERE amproc = 'bad_cmp3'::regproc;
@@ -235,7 +242,7 @@ $node->safe_psql(
($result, $stdout, $stderr) = $node->psql(
'postgres', q(
- SELECT bt_index_check('bttest_unique_idx3', true, true);+ SELECT bt_index_check('test_amcheck.bttest_unique_idx3', true, true);
));
ok( $stderr =~ /index uniqueness is violated for index "bttest_unique_idx3"/,
'detected uniqueness violation for index "bttest_unique_idx3"');
--
2.34.1
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-bugs@postgresql.org
Cc: pgsql@j-davis.com
Subject: Re: Query stuck with wait event IPC / ParallelFinish
In-Reply-To: <0f64b4c7fc200890f2055ce4d6650e9c2191fac2.camel@j-davis.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox