Date: Thu, 23 Nov 2017 13:46:36 -0800
From: Andres Freund <andres@anarazel.de>
To: Tomas Vondra <tv@fuzzy.cz>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Simon Riggs <simon@2ndquadrant.com>,
	pgsql-committers <pgsql-committers@postgresql.org>,
	Andrew Dunstan <andrew@dunslane.net>
Subject: Re: pgsql: Generational memory allocator
Message-ID: <20171123214636.unwkrkunr7m2bkii@alap3.anarazel.de>
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On 2017-11-23 22:34:57 +0100, Tomas Vondra wrote:
> > I think it's a legitimate complaint that postmaster.log wasn't captured
> > in this failure, but that's a buildfarm script oversight and hardly
> > Andres' fault.
> > 
> 
> Are the valgrind errors really written to postmaster log? I'm assuming it
> failed because valgrind ran into an issue and killed the process.

Yes. Search e.g. in
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=skink&dt=2017-09-18%2004%3A10%3A01
for VALGRINDERROR-BEGIN.

(You could argue that they're only written there in certain
configurations, because I'd assume it'd not work in e.g. syslog
configured systems, because valgrind just prints to stderr).


> Hmmm, I see. Presumably adding this to GenerationChunk (similarly to what we
> do in AllocChunkData) would address the issue:
> 
> #if MAXIMUM_ALIGNOF > 4 && SIZEOF_VOID_P == 4
> 	Size		padding;
> #endif
> 
> but I have no way to verify that (no access to such machine). I wonder why
> SlabChunk doesn't need to do that (perhaps a comment explaining that would
> be appropriate?).

Can't you just compile pg on a 32bit system and manually define MAXALIGN
to 8 bytes?

Greetings,

Andres Freund