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From Curtis Caravone <carav...@gmail.com>
Subject Re: stale views and scalability
Date Thu, 19 Mar 2009 15:21:26 GMT
Thanks.  I built the latest from the trunk and it works beautifully!

On Thu, Mar 19, 2009 at 4:54 AM, Adam Kocoloski
<adam.kocoloski@gmail.com> wrote:
> On Mar 19, 2009, at 7:39 AM, Curtis Caravone wrote:
>
>> The documentation for stale=ok describes the following semantics:
>>
>> The stale option can be used for higher performance ...  Using this
>> option essentially tells CouchDB that if a reference to the view index
>> is available in memory, go ahead and use it, even if it may be out of
>> date. ...if there is no view index pointer in memory, the behavior
>> with this option is that same as the behavior without the option...
>>
>> For views of large data sets with frequent updates, it is highly
>> likely that a random key or range query will fail to find its data in
>> memory, so the query will block until the view has been updated.  In
>> fact, multiple concurrent requests will all block until the update has
>> completed, which is an issue for scalability.  It seems like there
>> should be an option to immediately return the view query results based
>> on the latest available snapshot of the view index, regardless of
>> whether it is in memory or on disk.
>>
>> Is this something that's easy to implement?
>>
>> Curtis
>
> Hi Curtis, stale=ok works the way you want it to now.  A reference to the
> view index is still available even if the entire index is too large to fit
> in memory.  I think the language about finding a reference was meant to
> cover the case where the view had not been built or accessed yet.  Best,
>
> Adam
>

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