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Re: BDB log file factoids (prbly part of why they are so big)

From: ryan <ryan_at_netidea.com>
Date: 2003-04-06 00:41:44 CEST

> I'll go out on a speculative limb a bit here, and beyond the topic of
> log file mgt: it seems to me (on the basis of the "structure"
> document) that you pay a steep cost in database updates and log space
> to provide the "global-to-repository revision number" which
> effectively serializes all write txns to svn databases. Furthermore,
> I see little actual user benefit to that serialization: writes to
> unrelated projects or branches within a repository need not be


Database logs don't provide serializing. They provide the 'D' in ACID
compliance. It's possible to get serialization without logs, using OS level
semaphores for example.

Now, there is a question of if db4 doesn't recycle the logs often enough.
This really isn't a subversion question.

One possibility is if you consider each subversion repository a 'project'
then you could place a structure on top of that such as you're suggesting.
Thus allowing branching and merging between svn repos across the network.
Svn copy http://url1 http://url2

To branch from one repository to another, or perhaps to a local one:
Svn copy http://netrepository file:///home/me/mybranch

Note then that in this case the revision numbers are specific to a
project/branch as you suggest.

I really think the log file 'issue' is a red herring.


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Received on Sun Apr 6 00:42:13 2003

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