Re: [PATCH] lock transaction-current separately from current

On Oct 8, 2007 12:18 AM, Malcolm Rowe <malcolm-svn-dev@farside.org.uk> wrote:
> Ah, I wasn't clear.
>
> Currently, we do:
> open write-lock
> lock write-lock
> open transaction-current
> read
> close
> open temporary
> write
> fflush
> close
> rename to transaction-current
> open directory
> fflush directory
> close
> unlock write-lock
> close write-lock
>
> We could switch the lockfile to a new transaction-current-lock, sure,
> though it'd be much better if we switched to:
>
> open transaction-current
> lock
> read
> seek
> write
> fflush
> close

Haven't done this yet, but I did *finally* fix up the main patch to
lock transaction-current under a different lock from write-lock, and
committed it as r27735.

Differences from the last version are that we're locking
txn-current-lock instead of transaction-current itself (to avoid the
issue Malcolm mentions above), and that (also at Malcolm's suggestion)
there's no more stat on the lock file: just try to lock and create if
the attempt fails. Thanks! This should help throughput for highly
active repositories.

--dave

-- 
David Glasser | glasser_at_davidglasser.net | http://www.davidglasser.net/
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