At 10:52 PM 1/31/03 -0500, Tom Lane wrote:
>wade <wade@wavefire.com> writes:
>>   We recently upgraded a project from 7.2 to 7.3.1 to make use of some of
>> the cool new features in 7.3.  The installed version is CVS stable from
>> yesterday.  However, we noticed a major performance hit in POSIX regular
>> expression matches against columns using the ~* operator.  
>
>The only thought that comes to mind is that multibyte character sets are
>supported in 7.3 whereas they were optional (and not default) in 7.2.
>I'd not have expected a factor-of-150 performance hit from that, though.
>
>Could you rebuild your backend with profiling enabled and get a gprof
>summary of where the time is going?
>
>			regards, tom lane
>
>
Here is the profile information.  I included a log of the session that
generated it at the top of the gprof  output.  If there is any other info I
can help you with, please let me know.
http://arch.wavefire.com/pgregexgmon.txt

  -Wade Klaver

Mon, 03 Feb 2003 14:34:20 -0800
wade <wade@wavefire.com>
Re: POSIX regex performance bug in 7.3 Vs. 7.2 
wade <wade@wavefire.com> writes:
> Here is the profile information.  I included a log of the session that
> generated it at the top of the gprof  output.  If there is any other info I
> can help you with, please let me know.

A four-second test isn't long enough to gather any statistically
meaningful profile info.  On most machines, gprof samples 100 times per
second, so realistically you need a minute or two of runtime to have
trustworthy numbers.

Please replicate the rows in the table by a factor of ten or twenty or
so and try again.

			regards, tom lane

Mon, 03 Feb 2003 17:51:28 -0500
Tom Lane <tgl@sss.pgh.pa.us>
Re: POSIX regex performance bug in 7.3 Vs. 7.2 