On Sat, May 7, 2011 at 8:54 AM, Jonathan Ellis <jbel...@gmail.com> wrote: > On Sat, May 7, 2011 at 2:01 AM, Terje Marthinussen > <tmarthinus...@gmail.com> wrote: >> 1. Would it make sense to make full compactions occur a bit more aggressive. > > I'd rather reduce the performance impact of being behind, than do more > full compactions: https://issues.apache.org/jira/browse/CASSANDRA-2498 > >> 2. I >> would think the code should be smart enough to either trigger a full >> compaction and scrap the current queue, or at least merge some of those >> pending tasks into larger ones > > Not crazy but a queue-rewriter would be nontrivial. For now I'm okay > with saying "add capacity until compaction can mostly keep up." (Most > people's problem is making compaction LESS aggressive, hence > https://issues.apache.org/jira/browse/CASSANDRA-2156.) > > -- > Jonathan Ellis > Project Chair, Apache Cassandra > co-founder of DataStax, the source for professional Cassandra support > http://www.datastax.com >
Adjusting compaction and memtable settings is a tuning thing. Tuning is not usually a game changer. Every once in a while you hit a something wonderful and get 20% or 30% enhancement. But normally you are in the gain 1%-3% range. If you are seeing 600 pending compaction tasks regularly you almost definitely need more hardware.
