couchdb-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Curtis Caravone <carav...@gmail.com>
Subject stale views and scalability
Date Thu, 19 Mar 2009 11:39:01 GMT
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is available in memory, go ahead and use it, even if it may be out of
date.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

Mime
View raw message