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Re: svn commit: r1615458 - /subversion/branches/authzperf/subversion/libsvn_repos/log.c

From: Ivan Zhakov <ivan_at_visualsvn.com>
Date: Mon, 4 Aug 2014 18:30:32 +0400

On 4 August 2014 17:43, Branko Čibej <brane_at_wandisco.com> wrote:
> On 04.08.2014 14:22, Ivan Zhakov wrote:
>
> On 4 August 2014 02:47, <stefan2_at_apache.org> wrote:
>
> Author: stefan2
> Date: Sun Aug 3 22:47:07 2014
> New Revision: 1615458
>
> URL: http://svn.apache.org/r1615458
> Log:
> On the authzperf branch: Speed up authz-aware 'svn log' by sorting the
> paths before checking them. This lets the recent O(1) authz lookup
> optimization for sibbling paths kick in.
>
> * subversion/libsvn_repos/log.c
> (check_changed_path): Factored out loop content of ...
> (detect_changed): ... this. Use sorted iteration when applying authz.
>
> Stefan,
>
> Could you please confirm after that commit repository layer will do
> more (sort changed path) assuming that particular authz check function
> will work faster if calls will come in sorted order?
>
>
> That's the general idea, yes; authz lookups should be MUCH faster with the
> new in-memory representation, and the representation will work best with
> in-order sequences of queries. Note that there is no semantic change for
> existing authz files.
>
I don't like such implicit coupling between layers for improving
performance. It will be very fragile optimization and could break in
future making performance worse than before.

-- 
Ivan Zhakov
CTO | VisualSVN | http://www.visualsvn.com
Received on 2014-08-04 16:31:20 CEST

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