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Re: can libsvn_fs handle parallel writes to the same txn?

From: Garrett Rooney <rooneg_at_electricjellyfish.net>
Date: 2006-05-22 21:07:28 CEST

On 5/22/06, Ben Collins-Sussman <sussman@red-bean.com> wrote:
> On 5/22/06, Garrett Rooney <rooneg@electricjellyfish.net> wrote:
>
> > Making things work concurrently might be complex, but at the very
> > least it seems like we should think about adding some locking... If
> > you're going to append to the prototype rev file you lock it (both
> > file based and a mutex if you're a multithreaded process, just like we
> > do for the repos lock), same for the changes file, etc.
>
> Yup, this would make concurrent writes to the same txn safe. But it
> also means that FSFS would never get any of the benefits of
> parallel-processed commits. There might be multiple httpds all trying
> to write at once, but then serialized at the fs level.

Only so long as the actual write is occurring. I imagine there's
still gains to be had for reading network traffic concurrently,
preparing to do the write, etc. Not saying it couldn't be made
better, just that a "slow, but safe" approach seems best at the
beginning.

-garrett

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Received on Mon May 22 21:07:56 2006

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