Re: text_position worst case runtime
От
Tom Lane
Тема
Re: text_position worst case runtime
Дата
Msg-id
4512.1148077116@sss.pgh.pa.us
Ответ на
Re: text_position worst case runtime (Hannu Krosing)
Список
Дерево обсуждения
text_position worst case runtime Mark Dilger <pgsql@markdilger.com>
Re: text_position worst case runtime Tom Lane <tgl@sss.pgh.pa.us>
Re: text_position worst case runtime Mark Dilger <pgsql@markdilger.com>
Re: text_position worst case runtime "Jim C. Nasby" <jnasby@pervasive.com>
Re: text_position worst case runtime Hannu Krosing <hannu@skype.net>
Re: text_position worst case runtime Tom Lane <tgl@sss.pgh.pa.us>
Re: text_position worst case runtime Hannu Krosing <hannu@skype.net>
Re: text_position worst case runtime Hannu Krosing <hannu@skype.net>
Re: text_position worst case runtime Alvaro Herrera <alvherre@commandprompt.com>
Re: text_position worst case runtime Greg Stark <gsstark@mit.edu>
Re: text_position worst case runtime Tom Lane <tgl@sss.pgh.pa.us>
Re: text_position worst case runtime Alvaro Herrera <alvherre@commandprompt.com>
Re: text_position worst case runtime Tom Lane <tgl@sss.pgh.pa.us>
Re: text_position worst case runtime Greg Stark <gsstark@mit.edu>
Re: text_position worst case runtime Tom Lane <tgl@sss.pgh.pa.us>
Re: text_position worst case runtime Mark Dilger <pgsql@markdilger.com>
Hannu Krosing writes:
> I guess our regex implementation already uses boyer-moore or similar.
> Why not just expose the match position of substring('text' in 'regex')
> using some function, called match_position(int searched_text, int
> regex, int matchnum) ?
If it did that might be a nice solution, but I'm not sure that it does
use B-M ... I can't find either "Boyer" or "Moore" in its source code.
There's no particular reason to suppose offhand that a regex engine
would be faster than the naive code for fixed patterns.
regards, tom lane
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