Re: Undocumented(?) limits on regexp functions

From: Andrew Gierth <andrew(at)tao11(dot)riddles(dot)org(dot)uk>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Undocumented(?) limits on regexp functions
Date: 2018-08-14 13:16:42
Message-ID: 87zhxp3xer.fsf@news-spur.riddles.org.uk
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>>>>> "Tom" == Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

>> Should these limits:

>> a) be removed

Tom> Doubt it --- we could use the "huge" request variants, maybe, but
Tom> I wonder whether the engine could run fast enough that you'd want
Tom> to.

I do wonder (albeit without evidence) whether the quadratic slowdown
problem I posted a patch for earlier was ignored for so long because
people just went "meh, regexps are slow" rather than wondering why a
trivial splitting of a 40kbyte string was taking more than a second.

--
Andrew (irc:RhodiumToad)

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