Message-ID: <343ff14f-3060-4f88-9cc6-efdb390185df@mail.ru>
Date: Thu, 21 Dec 2023 15:45:47 +0700
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Subject: Re: Stack overflow issue
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To: Heikki Linnakangas <hlinnaka@iki.fi>, Sascha Kuhl <yogidabanli@gmail.com>
Cc: pgsql-hackers@lists.postgresql.org
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 <6b48c746-9704-46dc-b9be-01fe4137c824@iki.fi>
From: Egor Chindyaskin <kyzevan23@mail.ru>
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On 24/11/2023 21:14, Heikki Linnakangas wrote:
> What do you think?
Hello! Thank you for researching the problem! I'm more of a tester than 
a developer, so I was able to check the patches from that side.
I've configured the server with CFLAGS=" -O0" and cassert enabled and 
checked the following queries:

#CommitTransactionCommand
(n=1000000; printf "BEGIN;"; for ((i=1;i<=$n;i++)); do printf "SAVEPOINT 
s$i;"; done; printf "ERROR; COMMIT;") | psql >/dev/null

#ShowTransactionStateRec
(n=1000000; printf "BEGIN;"; for ((i=1;i<=$n;i++)); do printf "SAVEPOINT 
s$i;"; done; printf "SET log_min_messages = 'DEBUG5'; SAVEPOINT sp;") | 
psql >/dev/null

#MemoryContextCheck
(n=1000000; printf "begin;"; for ((i=1;i<=$n;i++)); do printf "savepoint 
s$i;"; done; printf "release s1;" ) | psql >/dev/null

#MemoryContextStatsInternal
(n=1000000; printf "BEGIN;"; for ((i=1;i<=$n;i++)); do printf "SAVEPOINT 
s$i;"; done; printf "SELECT 
pg_log_backend_memory_contexts(pg_backend_pid())") | psql >/dev/null

On my system, every of that queries led to a server crash at a number of 
savepoints in the range from 174,400 to 174,700.
With your patches applied, the savepoint counter goes well beyond these 
values, I settled on an amount of approximately 300,000 savepoints.
Your patches look good to me.

Best regards,
Egor Chindyaskin
Postgres Professional: http://postgrespro.com/