Horton

Re: Probable memory leak with ECPG and AIX

Guillaume Lelarge <guillaume@lelarge.info>

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From: Guillaume Lelarge <guillaume@lelarge.info>
To: Noah Misch <noah@leadboat.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Benoit Lobréau <benoit.lobreau@gmail.com>, PostgreSQL Developers <pgsql-hackers@postgresql.org>, "Dr. Michael Meskes" <michael.meskes@credativ.com>
Date: 2022-03-25T09:40:51Z
Lists: pgsql-hackers 
Le dim. 2 janv. 2022 à 01:07, Noah Misch <noah@leadboat.com> a écrit :

> On Sat, Jan 01, 2022 at 11:35:02AM -0500, Tom Lane wrote:
> > Noah Misch <noah@leadboat.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.

Commits

  1. Fix previous commit's ecpg_clocale for ppc Darwin.

  2. ecpglib: call newlocale() once per process.