Re: Wedged repositories [#6251]

> I think both times happened when I called Subversion from Emacs, and
> interrupted the operation.

OK, that will generally mean that recovery has to be run, as
you may have interrupted a thread of control while holding a
Berkeley DB data structure mutex.

> The hangs are quite black-and-white: the next operation simply hangs
> completely. It's not a grind-to-a-halt behavior at all. The
> grind-to-a-halt behavior you're talking about comes from page locks
> gradually accumulating across the database, right?

Yes.

> So if the
> application's page locking pattern is not randomly scattered across
> the database (for example, I'll bet Subversion hits the filesystem's
> root node pretty often), then you could get immediate hangs even from
> page locks, right?

Yes. But the root is generally locked read-only, and read locks
are shared, and so won't cause hangs. Write locks on the root
node are pretty rare.

> But this is speculation; I'll try to get a core dump.

This really, really sounds like a thread of control killed while
holding a data resource mutex, and recovery not being run.

I'd say it's time to check to see if that can happen in the code.

Regards,
--keith

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Keith Bostic
Sleepycat Software Inc. bostic@sleepycat.com
118 Tower Rd. +1-781-259-3139
Lincoln, MA 01773 http://www.sleepycat.com

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Received on Tue Jul 23 22:48:11 2002