From: Tom Lane <tgl@sss.pgh.pa.us>
To: George Pavlov <gpavlov@mynewplace.com>
Cc: pgsql-hackers@postgreSQL.org
Subject: Re: [GENERAL] query log corrupted-looking entries
Date: Wed, 18 Oct 2006 16:17:24 -0400
Message-ID: <29860.1161202644@sss.pgh.pa.us> (raw)
In-Reply-To: <11790.1161119352@sss.pgh.pa.us>
References: <8C5B026B51B6854CBE88121DBF097A8651DDE7@ehost010-33.exch010.intermedia.net>
<11790.1161119352@sss.pgh.pa.us>
I wrote:
> I checked around with some kernel/glibc gurus in Red Hat, and the
> consensus seemed to be that we'd be better off to bypass fprintf() and
> just send message strings to stderr using write() --- ie, instead of
> elog.c doing
> fprintf(stderr, "%s", buf.data);
> do
> write(fileno(stderr), buf.data, strlen(buf.data));
I did some strace'ing of the backend, and observed that even for very
long messages (upwards of 100K) the fprintf results in a single write()
call. This was true on both Fedora Core 5 and a pretty old HPUX version.
So it'd seem that most versions of libc already know about optimizing
fprintf-%s into a direct write(), and changing our code wouldn't change
the behavior. It'd be interesting to verify whether it's the same on
George's machine though.
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, gpavlov@mynewplace.com
Subject: Re: [GENERAL] query log corrupted-looking entries
In-Reply-To: <29860.1161202644@sss.pgh.pa.us>
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