Re: testing HS/SR - 1 vs 2 performance

From: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
To: Simon Riggs <simon(at)2ndQuadrant(dot)com>
Cc: Erik Rijkers <er(at)xs4all(dot)nl>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: testing HS/SR - 1 vs 2 performance
Date: 2010-04-16 08:29:54
Message-ID: 4BC82002.3010307@enterprisedb.com
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Simon Riggs wrote:
> On Tue, 2010-04-13 at 21:09 +0300, Heikki Linnakangas wrote:
>> A quick fix would be to check if there's any entries in the hash table
>> before scanning it. That would eliminate the overhead when there's no
>> in-progress transactions in the master. But as soon as there's even one,
>> the overhead comes back.
>
> Any fix should be fairly quick because of the way its modularised - with
> something like this in mind.
>
> I'll try a circular buffer implementation, with fastpath.

I started experimenting with a sorted array based implementation on
Tuesday but got carried away with other stuff. I now got back to that
and cleaned it up.

How does the attached patch look like? It's probably similar to what you
had in mind.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

Attachment Content-Type Size
knownassignedxids-array-2.patch text/x-diff 14.6 KB

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