Message-ID: <2a25eaf4-a3a4-5fd1-6241-9d7c73142085@gmail.com>
Date: Wed, 3 Apr 2024 15:00:00 +0300
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Subject: Re: SLRU optimization - configurable buffer pool and partitioning the
 SLRU lock
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To: Alvaro Herrera <alvherre@alvh.no-ip.org>,
 "Andrey M. Borodin" <x4mmm@yandex-team.ru>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, tender wang <tndrwang@gmail.com>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Tomas Vondra <tomas.vondra@enterprisedb.com>
References: <202402271733.43375fmfpr2f@alvherre.pgsql>
From: Alexander Lakhin <exclusion@gmail.com>
In-Reply-To: <202402271733.43375fmfpr2f@alvherre.pgsql>
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Hello Alvaro,

27.02.2024 20:33, Alvaro Herrera wrote:
> Here's the complete set, with these two names using the singular.
>

I've managed to trigger an assert added by 53c2a97a9.
Please try the following script against a server compiled with
-DTEST_SUMMARIZE_SERIAL (initially I observed this failure without the
define, it just simplifies reproducing...):
# initdb & start ...

createdb test
echo "
SELECT pg_current_xact_id() AS tx
\gset

SELECT format('CREATE TABLE t%s(i int)', g)
   FROM generate_series(1, 1022 - :tx) g
\gexec

BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
SELECT pg_current_xact_id();
SELECT pg_sleep(5);
" | psql test &

echo "
SELECT pg_sleep(1);
BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
SELECT 1 INTO a;
COMMIT;

BEGIN TRANSACTION ISOLATION LEVEL SERIALIZABLE;
SELECT 2 INTO b;
" | psql test

It fails for me with the following stack trace:
TRAP: failed Assert("LWLockHeldByMeInMode(SimpleLruGetBankLock(ctl, pageno), LW_EXCLUSIVE)"), File: "slru.c", Line: 366, 
PID: 21711
ExceptionalCondition at assert.c:52:13
SimpleLruZeroPage at slru.c:369:11
SerialAdd at predicate.c:921:20
SummarizeOldestCommittedSxact at predicate.c:1521:2
GetSerializableTransactionSnapshotInt at predicate.c:1787:16
GetSerializableTransactionSnapshot at predicate.c:1691:1
GetTransactionSnapshot at snapmgr.c:264:21
exec_simple_query at postgres.c:1162:4
...

Best regards,
Alexander