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From Bryan Pendleton <bpendle...@amberpoint.com>
Subject Re: Releasing latches when waiting for locks. When and why?
Date Sat, 18 Nov 2006 00:12:15 GMT
> When this method is used, the specified latch will be
> released if the lock cannot be obtained immediately, and that page
> will be re-latched when the lock has been obtained.

I'm just guessing here ...

I think that there are some fairly advanced Btree traversal algorithms,
in particular situations in which you are reading backward through a
Btree which may be undergoing concurrent structural modifications by
others, in which a primitive operation like the one you describe is crucial.

So perhaps this method was included in the Store in preparation for some
access method techniques which haven't yet been implemented?

thanks,

bryan



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