Horton

Re: Fix memory leak in gist_page_items() of pageinspect

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

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From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
To: Chao Li <li.evan.chao@gmail.com>
Cc: Postgres hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-12-12T09:00:08Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Use relation_close() more consistently in contrib/

  2. Use table/index_close() more consistently

  3. pageinspect: use index_close() for GiST index relation

Hi,

On Fri, Dec 12, 2025 at 04:50:09PM +0800, Chao Li wrote:
> Hi Hackers,
> 
> While reading the code of pageinspect, I just found a memory leak
> in gist_page_items():
> 
> ```
>    values[4] = CStringGetTextDatum(buf.data);
>    nulls[4] = false;
> ```
> 
> where CStringGetTextDatum() has made a copy of buf.data and assigned to
> value[4], however buf.data is never free-ed.

I did not look in details but I think that we should be in a short lived
memory context here so we generally prefer to avoid using pfree for those cases.

> This leak is inside a
> per-tuple loop, thus it should be fixed.

That might be a valid reason though. Do you have an idea of the "leak" size
based on the number of tuples?

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com