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Re: Inlining comparators as a performance optimisation

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Bruce Momjian <bruce(at)momjian(dot)us>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>, 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 20:04:45
Message-ID: CAFj8pRA5zqAi_dGS_UtwUMZfTb+zpRqUPKmDrFX+L6XSMnEi-Q@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
>>
>> [ 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.)
>
> Agreed.  Doing something once and doing something in the sort loop are
> two different overheads.
>
> I am excited by this major speedup Peter Geoghegan has found.  Postgres
> doesn't have parallel query, which is often used for sorting, so we are
> already behind some of the databases are compared against.  Getting this
> speedup is definitely going to help us.  And I do like the generic
> nature of where we are heading!
>

Oracle has not or had not parallel sort too, and I have a reports so
Oracle does sort faster then PostgreSQL (but without any numbers). So
any solution is welcome

Regards

Pavel

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