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Re: Berkeley DB in Subversion

From: Karl Fogel <kfogel_at_galois.collab.net>
Date: 2001-02-22 16:06:03 CET

Heh heh. Regarding the weird text (now corrected by Greg Stein) that
claimed sql databases had more reliable transactions than Berkeley DB,
I recently wrote this to Brian Behlendorf in a private mail:

> He's quite right to complain. I don't know what crack someone was
> smoking to claim that Berkeley DB has unreliable transactions.

Then, perhaps unconsciously suspecting the worst, I ran

   $ cvs annotate -r 1.10 future.texi

on the file to see who *had* written it. Of course, you already know
where this is going: it was me!

My apologies for the baseless libel, Michael :-). I honestly have no
memory what I was thinking.


Jim Blandy <jimb@zwingli.cygnus.com> writes:
> Michael, I did the Subversion filesystem design, and chose Berkeley DB
> for this implementation, precisely for its recoverability and
> transaction support. I have no idea who put that bit on the web site.
> If someone knows of problems with Berkeley DB's recoverability, I'm
> also very interested in hearing about them.
> As written, the web text seems to make a superstitious association
> between reliability and the query language a database uses. It's kind
> of embarrassing. I'd like to see it either substantiated, or revised.
> Subversion is not yet deployed, but when it is, I think it would be
> great to have it on Sleepycat's site, assuming the other developers
> don't object.
> > I'm Mike Olson. I work at Sleepycat Software. We develop,
> > distribute, and support Berkeley DB.
> >
> > I came across this excerpt on your Web site, and wanted to
> > follow up with you about it:
> >
> > SQL Back-End
> >
> > The Subversion filesystem will probably use Berkeley DB to store
> > data on disk; however, a real SQL database provides much more
> > reliable transactions. Someone can rewrite the filesystem back-end
> > to speak SQL.
> >
> > Needless to say, we disagree pretty strongly about the reliable
> > transactions statement. Berkeley DB survives failure without loss
> > of data, and without corruption. We're a bunch of database
> > heavyweights with significant time at the big relational companies.
> > We use the same techniques that the other vendors do for transactions,
> > including two-phase locking and write-ahead logging. I don't think
> > that a relational client/server system would be more reliable, but
> > I'm certain that it would be slower.
> >
> > Have you had problems with Berkeley DB that led you to make that
> > statement? If there's a problem, we'd like to know more so that
> > we can help you fix it.
> >
> > If you're in deployment now with Berkeley DB in Milestone 1, we'd
> > like to include you on our open source partners page. We've
> > recently redesigned the Web site, and will put up a new page in
> > the next few weeks that lists the open source projects that rely
> > on Berkeley DB. We'd be glad to have Subversion on that list,
> > if you're willing.
> >
> > Please do let me know about the reliability issue.
> >
> > mike
Received on Sat Oct 21 14:36:23 2006

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