From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jochen Erwied <jochen@erwied.eu>
Cc: Marti Raudsepp <marti@juffo.org>
Cc: muthu krishnan <muthu.krishnan.linux@gmail.com>
Cc: Jochen Erwied <jochen@pgsql-performance.erwied.eu>
Cc: pgsql-performance@postgresql.org
Subject: Re: Postgresql on itanium server
Date: Thu, 09 Jun 2011 12:20:02 -0400
Message-ID: <9435.1307636402@sss.pgh.pa.us> (raw)
In-Reply-To: <386582098.20110609125323@erwied.eu>
References: <BANLkTikknfi5L52PuPZuF1Eof1y1qdiY1w@mail.gmail.com>
<16710651848.20110609113019@erwied.eu>
<BANLkTi=MViJpg21a0-gv0fEx8kg8Zo4z1g@mail.gmail.com>
<BANLkTinaGxu-ruoJaPUoCgj5te7HvYSSwA@mail.gmail.com>
<386582098.20110609125323@erwied.eu>
Jochen Erwied <jochen@erwied.eu> writes:
> Thursday, June 9, 2011, 12:45:06 PM you wrote:
>> As the URL mentions, you can build with CFLAGS=-ffast-math, that
>> should work for PostgreSQL too.
> I just tried this with the source for 9.0.4, at least with this version the
> build will not complete since there is a check in
> src/backend/utils/adt/date.c throwing an error if FAST_MATH is active.
Yeah. See
http://archives.postgresql.org/pgsql-bugs/2002-09/msg00169.php
and following discussions, which eventually led to adding the #error.
Now this was all done in regards to PG's original floating-point
timestamp implementation. It's possible that in an integer-datetimes
build (which is now the default) we don't need to forbid -ffast-math to
prevent strange datetime results. But nobody's done the work to prove
that, because there isn't any particularly good reason to enable
-ffast-math in a database in the first place. (Other than coping with
brain-dead platforms, I guess.)
However ... I'm not sure I believe that this is related to the OP's
problem anyway. Postgres doesn't normally work with any denormalized
numbers, so the messages he's seeing probably stem from some other sort
of shortcoming in the hardware FP support. It would be interesting to
see specific examples of SQL operations that trigger the kernel message.
regards, tom lane
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-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, jochen@erwied.eu, marti@juffo.org, muthu.krishnan.linux@gmail.com, jochen@pgsql-performance.erwied.eu
Subject: Re: Postgresql on itanium server
In-Reply-To: <9435.1307636402@sss.pgh.pa.us>
* 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