Re: Re: patch: fix performance problems with repated decomprimation of varlena values in plpgsql

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Noah Misch <noah(at)leadboat(dot)com>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Re: patch: fix performance problems with repated decomprimation of varlena values in plpgsql
Date: 2011-01-28 19:09:15
Message-ID: AANLkTini3FQrU8KZ47mXAikbGLSs=bJ677S+A+2rf4jn@mail.gmail.com
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On Tue, Jan 25, 2011 at 11:29 AM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
> variant a) my first patch - detoast on first usage with avoiding to
> useless detoast checking
> variant b) my first patch - detoast on first usage without avoiding to
> useless detoast checking
>
> time for 1 - about 300 ms, a is bout 1.5% faster than b
> time for 2 - about 30000 ms, a is about 3% faster than b

This makes your approach sound pretty good, but it sounds like we
might need to find a better way to structure the code.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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