Horton

Re: BUG #14897: Segfault on statitics SQL request

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Dmitry Dolgov <9erthalion6@gmail.com>
Cc: Michael Paquier <michael.paquier@gmail.com>, Vincent Lachenal <vincent.lachenal@gmail.com>, PostgreSQL mailing lists <pgsql-bugs@postgresql.org>
Date: 2017-11-11T16:36:56Z
Lists: pgsql-bugs 
Dmitry Dolgov <9erthalion6@gmail.com> writes:
>> On 11 November 2017 at 09:39, Michael Paquier <michael.paquier@gmail.com>
> wrote:
>> My laptop uses Arch, and I can see the crash easily when compiling
>> with gcc 7.2 which is the one bundled in the core package set

> Yes, I forgot to mention, that I also used quite recent version of gcc
> (GCC) 8.0.0 20170805 (experimental).

Would you guys who are seeing the problem note whether the address of
the int128 field is 16-aligned, or only 8-aligned?

Also, it'd be real useful to see some disassembly around the point of
the crash, so that we can check whether the compiler is using SIMD
instructions.  (Or just get the compiler to generate a numeric.s file
with -S.)

I'm pretty suspicious that this is where the problem is, but it would
be good to have confirmation before we put effort into a fix.

			regards, tom lane

Commits

  1. Prevent int128 from requiring more than MAXALIGN alignment.

  2. Rearrange c.h to create a "compiler characteristics" section.