Thanks for your comments Aristotle - And no, you're not missing anything, it is suppose to be a 'read lock' associated with the EXISTS method.

It's probably best to get a shared lock right when you tie, then upgrade it to an exclusive lock as soon as you need to write to the file and not downgrade to a shared lock from an exclusive one ever as that will jeopardize integrity.

Are there are any caveats or disadvantages which I should be aware of in acquiring and holding a shared lock for the duration of the life of the tied object?

 

Update - Curiously, while I would expect that a shared lock would be appropriate for the EXISTS method, the module MLDBM::Sync which perrin referred me to here actually calls upon an exclusive lock for calling upon the EXISTS method of the underlying file store.

 

In reply to Re: Re: Locking and synchronisation within tied hashes by rob_au
in thread Locking and synchronisation within tied hashes by rob_au

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