| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | postgres performance list <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Shortcutting too-large offsets? |
| Date: | 2011-09-30 18:44:25 |
| Message-ID: | 4E860E09.7090107@agliodbs.com |
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| Lists: | pgsql-performance |
Tom,
> In principle, yeah, we could make it do that, but it seems like a likely
> source of maintenance headaches. This example is not exactly compelling
> enough to make me want to do it. Large OFFSETs are always going to be
> problematic from a performance standpoint, and the fact that we could
> short-circuit this one corner case isn't really going to make them much
> more usable.
It's not that uncommon of a corner case though; it's one which happens
all the time in webapps which paginate. People just have to ask for a
page after the end. It's really a question of how simple the code to
make the optimization would be; if it would be a 5-line patch, then it's
worth it; if it would be a 110-line refactor, no.
Lemme see if I can figure it out ...
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com
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