On Sun, May 16, 2010 at 2:52 PM, Joost Ouwerkerk <jo...@openplaces.org> wrote: > Meanwhile. I'm still getting TimedOutException errors when mapping this > 30-million row table, even when retrieving no data at all. It looks like it > is related to disk activity on "hot" nodes (when the same cassandra node has > to handle many concurrent requests for adjacent range slices). Using 0.7 > trunk branch doesn't appear to alleviate it. CPU load is at about 25% when > this happens. Is there some kind of synchronization that might prevent the > same file from being scanned by multiple threads?
No, but there's only `concurrent_reads` threads serving reads and if you have a lot of ops in the queue ahead of you then that would do it. (pending tasks in row stage under cassandra.concurrent jmx.) -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of Riptano, the source for professional Cassandra support http://riptano.com
