Re: maintain_cluster_order_v5.patch

From: Jeff Davis <pgsql(at)j-davis(dot)com>
To: "phb07(at)apra(dot)asso(dot)fr" <phb07(at)apra(dot)asso(dot)fr>
Cc: pgsql-performance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: maintain_cluster_order_v5.patch
Date: 2009-10-19 22:05:53
Message-ID: 1255989953.31947.114.camel@monkey-cat.sm.truviso.com
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On Mon, 2009-10-19 at 21:32 +0200, phb07(at)apra(dot)asso(dot)fr wrote:
> Hi all,
>
> The current discussion about "Indexes on low cardinality columns" let
> me discover this
> "grouped index tuples" patch (http://community.enterprisedb.com/git/)
> and its associated
> "maintain cluster order" patch
> (http://community.enterprisedb.com/git/maintain_cluster_order_v5.patch)
>
> This last patch seems to cover the TODO item named "Automatically
> maintain clustering on a table".

The TODO item isn't clear about whether the order should be strictly
maintained, or whether it should just make an effort to keep the table
mostly clustered. The patch mentioned above makes an effort, but does
not guarantee cluster order.

> As this patch is not so new (2007), I would like to know why it has
> not been yet integrated in a standart version of PG (not well
> finalized ? not totaly sure ? not corresponding to the way the core
> team would like to address this item ?) and if there are good chance
> to see it committed in a near future.

Search the archives on -hackers for discussion. I don't think either of
these features were rejected, but some of the work and benchmarking have
not been completed.

If you can help (either benchmark work or C coding), try reviving the
features by testing them and merging them with the current tree. I
recommend reading the discussion first, to see if there are any major
problems.

Personally, I'd like to see the GIT feature finished as well. When I
have time, I was planning to take a look into it.

Regards,
Jeff Davis

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