Re: Probable memory leak with ECPG and AIX

From: Guillaume Lelarge <guillaume(at)lelarge(dot)info>
To: Noah Misch <noah(at)leadboat(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Benoit Lobréau <benoit(dot)lobreau(at)gmail(dot)com>, PostgreSQL Developers <pgsql-hackers(at)postgresql(dot)org>, "Dr(dot) Michael Meskes" <michael(dot)meskes(at)credativ(dot)com>
Subject: Re: Probable memory leak with ECPG and AIX
Date: 2022-03-25 09:40:51
Message-ID: CAECtzeXE0vfvrUHwDJ56rgMD6axDH7n5K2vyfLTcU4vkUK4yaQ@mail.gmail.com
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Le dim. 2 janv. 2022 à 01:07, Noah Misch <noah(at)leadboat(dot)com> a écrit :

> On Sat, Jan 01, 2022 at 11:35:02AM -0500, Tom Lane wrote:
> > Noah Misch <noah(at)leadboat(dot)com> writes:
> > > I get the same results. The leak arises because AIX freelocale()
> doesn't free
> > > all memory allocated in newlocale(). The following program uses
> trivial
> > > memory on GNU/Linux, but it leaks like you're seeing on AIX:
> >
> > Bleah.
> >
> > > If you have access to file an AIX bug, I recommend doing so. If we
> want
> > > PostgreSQL to work around this, one idea is to have ECPG do this
> newlocale()
> > > less often. For example, do it once per process or once per connection
> > > instead of once per ecpg_do_prologue().
> >
> > It's worse than that: see also ECPGget_desc(). Seems like a case
> > could be made for doing something about this just on the basis
> > of cycles expended, never mind freelocale() bugs.
>
> Agreed. Once per process seems best. I only hesitated before since it
> means
> nothing will free this storage, which could be annoying in the context of
> Valgrind and similar. However, ECPG already has bits of never-freed
> memory in
> the form of pthread_key_create() calls having no pthread_key_delete(), so I
> don't mind adding a bit more.
>

Did this get anywhere? Is there something we could do to make this move
forward?

--
Guillaume.

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