Re: Fwd: Effects of importing over 18000 items into repository as one commit transaction

Ben Collins-Sussman wrote:
> On 1/10/06, Garrett Rooney <rooneg@electricjellyfish.net> wrote:
>
>>On 1/10/06, Julian Foad <julianfoad@btopenworld.com> wrote:
>>
>>
>>>If the large revision is causing a massive slow-down in "svn log", that's
>>>certainly something we ought to investigate, but it might be a low priority if
>>>it is only moderate and/or only occurs on revision 1.
>>
>>If that is the case, it tends to be because of the need to run authz
>>checks on large numbers of paths, and other than turning off path
>>based authz there isn't a lot that can be done about it.

Not by the user, maybe. Presumably what can be done about it from our point of
view is to ensure that the authz-checking code is called efficiently - in such
a way that it can accept and reject whole sub-trees without having to evaluate
every path individually.

> Right. For more explanation, see our notes/authz_policy.txt file.

That document mentions the problem of O(N) behaviour for copy operations, in
section 3 of each "chapter". It doesn't mention such a problem for any other
situation. Do you want to patch it to warn of O(N) behaviour in other or all
cases?

This document also mentions that it need not be that slow:

> Depending on the specific path-based authz module being used,
> however, there are sometimes solutions that aren't quite so
> expensive as O(N).

- Julian

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Received on Wed Jan 11 15:04:42 2006