Re: Inlining comparators as a performance optimisation

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Peter Geoghegan <peter(at)2ndquadrant(dot)com>, PG Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Inlining comparators as a performance optimisation
Date: 2011-12-02 15:11:19
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Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> OK, but I think it's also going to cost you an extra syscache lookup,
> no? You're going to have to check for this new support function
> first, and then if you don't find it, you'll have to check for the
> original one. I don't think there's any higher-level caching around
> opfamilies to save our bacon here, is there?

[ shrug... ] If you are bothered by that, get off your duff and provide
the function for your datatype. But it's certainly going to be in the
noise for btree index usage, and I submit that query parsing/setup
involves quite a lot of syscache lookups already. I think that as a
performance objection, the above is nonsensical. (And I would also
comment that your proposal with a handle is going to involve a table
search that's at least as expensive as a syscache lookup.)

regards, tom lane

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