From: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
---|---|
To: | Neil Conway <nconway(at)klamath(dot)dyndns(dot)org> |
Cc: | Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: compile bug in HEAD? |
Date: | 2002-04-18 01:41:07 |
Message-ID: | 200204180141.g3I1f7Z15567@candle.pha.pa.us |
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Lists: | pgsql-hackers |
Neil Conway wrote:
> On Wed, Mar 27, 2002 at 07:56:15PM -0500, Peter Eisentraut wrote:
> > Neil Conway writes:
> >
> > > I'm curious; why is this "not the right fix"? According to the manpage:
> > >
> > > -l turns on maximum compatibility with the original
> > > AT&T lex implementation. Note that this does not
> > > mean full compatibility. Use of this option
> > > costs a considerable amount of performance...
> >
> > The manpage also lists the specific incompatibilities. I think we should
> > not be affected by them, but someone better check before removing the -l.
>
> AFAICT current sources don't actually use "-l" anywhere.
>
> However, it does appear that we can tweak flex for more performance
> (usually at the expense of a larger generated parser). In particular, it
> looks like we could use "-Cf" or "-CF". Is this a good idea?
>
> While we're on the subject of minor optimizations, is there a reason why
> we execute gcc with "-O2" rather than "-O3" during compilation?
Added to TODO:
* Try flex flags -Cf and -CF to see if performance improves
--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
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