There's likely 2 things occurring 1) the cfhistograms error is due to https://issues.apache.org/jira/browse/CASSANDRA-8028 Which is resolved in 2.1.3. Looks like voting is under way for 2.1.3. As rcoli mentioned, you are running the latest open source of C* which should be treated as beta until a few dot releases are published.
2) compaction running all the time doesn't mean that compaction is "caught up". It's possible that the nodes are behind in compaction which will cause slow reads. C* read performance is typically associated with disk system performance, both to service reads from disk as well as to enable fast background processing, like compaction. You mentioned raided hdds. What type of raid is configured? How fast are your disks responding? You may want to check iostat to see how large your queues and awaits are. If the await is high, then you could be experiencing disk perf issues impacting reads. Hope this helps On Jan 9, 2015, at 9:29 AM, Roni Balthazar <ronibaltha...@gmail.com> wrote: Hi there, The compaction remains running with our workload. We are using SATA HDDs RAIDs. When trying to run cfhistograms on our user_data table, we are getting this message: nodetool: Unable to compute when histogram overflowed Please see what happens when running some queries on this cf: http://pastebin.com/jbAgDzVK Thanks, Roni Balthazar On Fri, Jan 9, 2015 at 12:03 PM, datastax <jlacefi...@datastax.com> wrote: Hello You may not be experiencing versioning issues. Do you know if compaction is keeping up with your workload? The behavior described in the subject is typically associated with compaction falling behind or having a suboptimal compaction strategy configured. What does the output of nodetool cfhistograms <keyspace> <table> look like for a table that is experiencing this issue? Also, what type of disks are you using on the nodes? Sent from my iPad On Jan 9, 2015, at 8:55 AM, Brian Tarbox <briantar...@gmail.com> wrote: C* seems to have more than its share of "version x doesn't work, use version y " type issues.... On Thu, Jan 8, 2015 at 2:23 PM, Robert Coli <rc...@eventbrite.com> wrote: On Thu, Jan 8, 2015 at 11:14 AM, Roni Balthazar <ronibaltha...@gmail.com> wrote: We are using C* 2.1.2 with 2 DCs. 30 nodes DC1 and 10 nodes DC2. https://engineering.eventbrite.com/what-version-of-cassandra-should-i-run/ 2.1.2 in particular is known to have significant issues. You'd be better off running 2.1.1 ... =Rob -- http://about.me/BrianTarbox
