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Re: SVN Update/Commit Concurrency

From: Ulrich Eckhardt <eckhardt_at_satorlaser.com>
Date: Thu, 10 Jan 2008 10:29:36 +0100

Note up front: I didn't actually look at the sources, so I might be wrong.

On Thursday 10 January 2008, Daniel Becroft wrote:
> What is the method that SVN uses to control commits that happen during
> another user's update?
>
> For example, in the following scenario:
>
> 1. [UserA] svn update (HEAD is 100).
> 2. [UserB] svn commit (HEAD is 101) - happens while UserA's update is
> happening
>
> When UserA's update has completed, will the working copy revision number be
> 100, or 101?

It will be 100.

> I'm guessing that the first thing that the 'svn update' would do is to get
> the HEAD revision and store that, so it becomes a 'svn update --revision
> 100' command?

Right. The first thing is probably that it determines the head revision. From
then on, even if the head revision changes, the revision itself doesn't (they
are treated as almost immutable) so these changes don't affect the ongoing
read operation.

> I've attempted to replicate this situation without success - I can't seem
> to make UserA's update go long enough.

Throttle the network. ;)

Just wondering, but what do you need this info for?

Uli

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Received on 2008-01-10 10:31:02 CET

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