Re: wchareq improvement
| От | a_ogawa |
|---|---|
| Тема | Re: wchareq improvement |
| Дата | |
| Msg-id | PIEMIKOOMKNIJLLLBCBBKEIECHAA.a_ogawa@hi-ho.ne.jp обсуждение исходный текст |
| Ответ на | Re: wchareq improvement (Bruce Momjian <pgman@candle.pha.pa.us>) |
| Список | 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
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