Re: POSIX regex performance bug in 7.3 Vs. 7.2

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: wade <wade(at)wavefire(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: POSIX regex performance bug in 7.3 Vs. 7.2
Date: 2003-02-04 04:08:14
Message-ID: 2603.1044331694@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Next question: may I guess that you weren't using MULTIBYTE in 7.2?

After still more digging, I'm coming round to the opinion that the
problem is that MULTIBYTE is forced on in 7.3, and this imposes a
factor-of-256 overhead in a bunch of the operations in regcomp.c.
In particular, compiling a case-independent regex is now hugely
more expensive than it used to be.

The parties who wanted to force MULTIBYTE on promised that there
would be no such penalties :-(

regards, tom lane

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 2003-02-04 04:33:08 Re: regression failure on freebsd/alpha
Previous Message Tom Lane 2003-02-04 03:02:42 Re: POSIX regex performance bug in 7.3 Vs. 7.2