pg.ddx.io  pgsql-bugs@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Michael Paquier <michael.paquier@gmail.com>
Cc: Vincent Lachenal <vincent.lachenal@gmail.com>
Cc: PostgreSQL mailing lists <pgsql-bugs@postgresql.org>
Subject: Re: BUG #14897: Segfault on statitics SQL request
Date: Sat, 11 Nov 2017 09:45:12 -0800
Message-ID: <20171111174512.ikd3zrx2i5ssxpww@alap3.anarazel.de> (raw)
In-Reply-To: <3914.1510422100@sss.pgh.pa.us>
References: <CAA2tJ7p72wbuHEzOA_g2V4YcmeDPHYKggenTR4dXG=kSpCiO8Q@mail.gmail.com>
	<14075.1510352167@sss.pgh.pa.us>
	<CA+q6zcXe9aV5NV88u9Y=vMp+=fP7QOXgTyFQhzuvmCvTBvb_kQ@mail.gmail.com>
	<17617.1510355215@sss.pgh.pa.us>
	<CAB7nPqR7mWvtnALZF93oez_v03NFCJ8dXP9CNicaUDv3KjDbYw@mail.gmail.com>
	<CA+q6zcVE2FQ9irhENEy=2WjRWgV2hyzfYyOXFs36w=hsk4faBw@mail.gmail.com>
	<644.1510418216@sss.pgh.pa.us>
	<CA+q6zcWwjTNgA6JiqQ5L-oAFF5X9ONtKSAvznte63A7Zb7zaww@mail.gmail.com>
	<20171111171620.td6vtnmijcloj6k5@alap3.anarazel.de>
	<3914.1510422100@sss.pgh.pa.us>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-bugs>

On 2017-11-11 12:41:40 -0500, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > That's using SSE, which requires 16byte alignment IIRC.  I think we need
> > a function that properly allocate int128 vars with the right alignment -
> > don't think we want to go for full 16byte alignment for everything.
> 
> Yeah, changing MAXALIGN is out of the question.  I'm thinking about
> another flag bit for MemoryContextAllocExtended.  Do we need to think
> about other use-cases besides int128?  Should we just force 16-byte
> alignment on all architectures, or does it need to be platform-specific?

I'm not sure we want to
a) Rely on one alignment being enough for everybody.
b) Additionally burden already hot code paths with a growing number of
   alignment flag tests, and the necessary math.

How about a MemoryContextAllocAligned(context, size, alignto, flags)
that passes on most flags but adds the necessary overhead to size, and
padds the result appropriately?

Greetings,

Andres Freund


-- 
Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-bugs



view thread (39+ messages)  latest in thread

Message-ID: <20171111174512.ikd3zrx2i5ssxpww@alap3.anarazel.de>
Permalink:  ../20171111174512.ikd3zrx2i5ssxpww@alap3.anarazel.de/
Also on:    postgresql.org/message-id/20171111174512.ikd3zrx2i5ssxpww@alap3.anarazel.de

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-bugs@postgresql.org
  Cc: andres@anarazel.de, tgl@sss.pgh.pa.us, 9erthalion6@gmail.com, michael.paquier@gmail.com, vincent.lachenal@gmail.com
  Subject: Re: BUG #14897: Segfault on statitics SQL request
  In-Reply-To: <20171111174512.ikd3zrx2i5ssxpww@alap3.anarazel.de>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox