Horton

Re: [HACKERS] Deadlock in XLogInsert at AIX

Michael Paquier <michael.paquier@gmail.com>

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From: Michael Paquier <michael.paquier@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Robert Haas <robertmhaas@gmail.com>, Noah Misch <noah@leadboat.com>, Andres Freund <andres@anarazel.de>, Heikki Linnakangas <hlinnaka@iki.fi>, Konstantin Knizhnik <k.knizhnik@postgrespro.ru>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Bernd Helmle <mailings@oopsware.de>
Date: 2018-01-23T01:59:46Z
Lists: pgsql-hackers 
On Mon, Jan 22, 2018 at 04:23:55PM -0500, Tom Lane wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> I agree with Noah.  It's true that having unfixed bugs isn't
>> particularly good, but it doesn't justify activating a CommitFest
>> entry under someone else's name.
> 
> Agreed.  The CF app is not a bug tracker.

OK, thanks for the feedback. Based on that I am deleting this entry from
the CF. And my apologies for the noise.

>> If nobody is willing to put in the effort to keep AIX supported under
>> XLC, then we should just update the documentation to say that it isn't
>> supported.  Our support for that platform is pretty marginal anyway if
>> we're only supporting it up through 6.1; that was released in 2007 and
>> went out of support in Q2 of last year.
> 
> Huh?  We have somebody just upthread saying that they're working out
> issues on newer AIX.  We should at least give them time to finish
> that research before making any decisions.

Yes, Tony stated so, still he has not published any patches
yet. Regarding the potential documentation impact, please let me suggest
just to mention that support of XLC up to 12.1 is supported, per the
buildfarm this is rather stable and does not face the same issues as
what we are seeing with XLC 13.1. Is there any point to wait for the
docs to not say that now? As far as I know, if support for XLC 13.1
moves on in the future we can update the docs so as the support range is
increased later on.
--
Michael

Commits

  1. For all ppc compilers, implement compare_exchange and fetch_add with asm.

  2. For PowerPC instruction "addi", use constraint "b".

  3. For all ppc compilers, implement pg_atomic_fetch_add_ with inline asm.

  4. Replace xlc __fetch_and_add() with inline asm.

  5. Test pg_atomic_fetch_add_ with variable addend and 16-bit edge cases.