Re: Pathological regexp match
От | Alvaro Herrera |
---|---|
Тема | Re: Pathological regexp match |
Дата | |
Msg-id | 20100129025922.GA1793@alvh.no-ip.org обсуждение исходный текст |
Ответ на | Pathological regexp match (Michael Glaesemann <michael.glaesemann@myyearbook.com>) |
Ответы |
Re: Pathological regexp match
Re: Pathological regexp match |
Список | pgsql-hackers |
Hi Michael, Michael Glaesemann wrote: > We came across a regexp that takes very much longer than expected. > > PostgreSQL 8.4.1 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-44), 64-bit > > SELECT 'ooo...' ~ $r$Z(Q)[^Q]*A.*?(\1)$r$; -- omitted for email brevity The ? after .* is pointless. If you remove it, the query returns immediately. (There's a badly needed CHECK_FOR_INTERRUPTS in this code BTW) -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc.
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