>>Watching trends on these pools for increases in the pending tasks >>column is an excellent indicator of the need to add additional capacity.
Additional capacity meaning add more writers and reader threads to handle the requests ? On Tue, Oct 1, 2013 at 12:22 PM, Robert Coli <rc...@eventbrite.com> wrote: > On Wed, Aug 28, 2013 at 5:47 AM, Girish Kumar <girishkuma...@gmail.com>wrote: > >> When high number of Pending tasks are showing up what it means to >> cassandra? What are the reasons for high number pending tasks? Does that >> mean Cassandra is overloaded ? >> > > It means that tasks have been queued to run inside of a Thread Pool, but > are not currently running. A given task moves from Pending to Active state, > and then Completed. "Blocked" is "I attempted to move something from > Pending to Active, but was unable to." > > http://www.datastax.com/docs/1.0/operations/monitoring > " > Cassandra maintains distinct thread pools for different stages of > execution. Each of these thread pools provide statistics on the number of > tasks that are active, pending and completed. Watching trends on these > pools for increases in the pending tasks column is an excellent indicator > of the need to add additional capacity. > " > > =Rob > >
