| From: | a_ogawa <a_ogawa(at)hi-ho(dot)ne(dot)jp> |
|---|---|
| To: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> |
| Cc: | pgsql-patches(at)postgresql(dot)org |
| Subject: | Re: wchareq improvement |
| Date: | 2005-05-26 14:01:37 |
| Message-ID: | PIEMIKOOMKNIJLLLBCBBKEIECHAA.a_ogawa@hi-ho.ne.jp |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-patches |
Bruce Momjian wrote:
>
> Patch applied with adjustment --- the second part of your patch that
> skips comparing the first byte seemed unnecessary. It seemed likely
> to cause a cpu stall, so just doing the loop seemed faster.
>
> Did you test if the second part of your patch actually caused a speedup?
Well, I measured the performance today. As a result, I confirmed the
second part of my patch is unnecessary as you pointed it out.
Thanks for comment and applying patch.
> a_ogawa wrote:
> >
> > In SQL that uses 'like' operator, wchareq is used to compare characters.
> >
> > At the head of wchareq, length of (multibyte) character is compared by
> > using pg_mblen. Therefore, pg_mblen is executed many times, and it
> > becomes a bottleneck.
regards,
--- Atsushi Ogawa
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2005-05-26 14:10:50 | Re: pgsql: Add PL/pgSQL SQLSTATE and SQLERRM support which sets these values |
| Previous Message | Peter Eisentraut | 2005-05-26 10:59:51 | Re: Implementation of SQLSTATE and SQLERRM variables |