From: Tom Lane <tgl@sss.pgh.pa.us>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: wliang@stu.xidian.edu.cn, pgsql-bugs <pgsql-bugs@lists.postgresql.org>
Subject: Re: Report a potential memory leak in setup_config()
Date: Tue, 15 Feb 2022 11:33:26 -0500
Message-ID: <3052163.1644942806@sss.pgh.pa.us> (raw)
In-Reply-To: <A7070803-5A15-486E-AE04-ECC13CD10038@yesql.se>
References: <64ee7543.20d.17efb1270ca.Coremail.wliang@stu.xidian.edu.cn>
<A7070803-5A15-486E-AE04-ECC13CD10038@yesql.se>
Daniel Gustafsson <daniel@yesql.se> writes:
> On 15 Feb 2022, at 02:49, wliang@stu.xidian.edu.cn wrote:
>> Specifically, at line 1095, function pretty_wal_size() is called, which allocates a chunk of memory by using pg_malloc and returns it. However, the return chunk is directly passed to snprintf as its 3rd parameter. As a result, there is a memory leak.
> PostgreSQL isn't all too concerned about small static leaks in short lived
> programs, like initdb. Memory will be freed shortly when the program exits.
> Complicating the code to save 28 bytes seems hardly worth it, but if you feel
> strongly about it I suggest proposing a patch to fix it.
Yeah. A quick run of initdb under valgrind reports
==3051337== LEAK SUMMARY:
==3051337== definitely lost: 893,446 bytes in 47 blocks
==3051337== indirectly lost: 4,490 bytes in 51 blocks
==3051337== possibly lost: 0 bytes in 0 blocks
==3051337== still reachable: 2,403 bytes in 22 blocks
==3051337== suppressed: 0 bytes in 0 blocks
It might be worth trying to knock that down a bit, but I wouldn't
start with a one-time leak of 28 bytes. It looks like the biggest
offender is that we don't bother trying to reclaim the lines
malloc'd by readfile() and replace_token(). Fixing that is *maybe*
worth the trouble, but TBH no one has complained about initdb's
memory consumption.
regards, tom lane
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: tgl@sss.pgh.pa.us, daniel@yesql.se, pgsql-bugs@lists.postgresql.org
Subject: Re: Report a potential memory leak in setup_config()
In-Reply-To: <3052163.1644942806@sss.pgh.pa.us>
* 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