Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id 26D77B5DBCB for ; Thu, 9 Jun 2011 13:20:16 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 79164-07 for ; Thu, 9 Jun 2011 16:20:09 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id BDC98B5DBC0 for ; Thu, 9 Jun 2011 13:20:08 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id p59GK2Bu009436; Thu, 9 Jun 2011 12:20:02 -0400 (EDT) To: Jochen Erwied cc: Marti Raudsepp , muthu krishnan , Jochen Erwied , pgsql-performance@postgresql.org Subject: Re: Postgresql on itanium server In-reply-to: <386582098.20110609125323@erwied.eu> References: <16710651848.20110609113019@erwied.eu> <386582098.20110609125323@erwied.eu> Comments: In-reply-to Jochen Erwied message dated "Thu, 09 Jun 2011 12:53:23 +0200" Date: Thu, 09 Jun 2011 12:20:02 -0400 Message-ID: <9435.1307636402@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201106/103 X-Sequence-Number: 44036 Jochen Erwied 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