Re: Postgresql on itanium server - Mailing list pgsql-performance

From Marti Raudsepp
Subject Re: Postgresql on itanium server
Date
Msg-id BANLkTinaGxu-ruoJaPUoCgj5te7HvYSSwA@mail.gmail.com
Whole thread Raw
In response to Re: Postgresql on itanium server  (muthu krishnan <muthu.krishnan.linux@gmail.com>)
Responses Re: Postgresql on itanium server
List pgsql-performance
On Thu, Jun 9, 2011 at 13:03, muthu krishnan
<muthu.krishnan.linux@gmail.com> wrote:
> Thank you for suggesting the valuable URL, we are getting 3 "floating point
> assist fault" error for every second, will it impact the performance for
> postgresql?

Probably.

The kernel throttles these messages, so you're probably performing
many more of these calculations than the number of messages.

> Is there any option to turn on "flush to zero mode" in itanium cpu while
> compiling postgresql from source?

As the URL mentions, you can build with CFLAGS=-ffast-math, that
should work for PostgreSQL too.

But since you know you're operating with denormal numbers, you WILL
get different results to queries. Whether that's a problem for you
depends on your application. You could start getting division by zero
errors for instance.

Regards,
Marti

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