On Mon, Nov 12, 2012 at 3:35 PM, cem <cayiro...@gmail.com> wrote: > We are currently facing a performance issue with counter column families. I > see lots of pending ReplicateOnWriteStage tasks in tpstats. Then I disabled > replicate_on_write. It helped a lot. I want to use like that but I am not > sure how to use it.
Quoting Sylvain, one of the primary authors/maintainers of the Counters support... https://issues.apache.org/jira/browse/CASSANDRA-3868 " I don't disagree about the efficiency of the valve, but at what price? 'Bootstrapping a node will make you lose increments (you don't know which ones, you don't know how many and this even if nothing goes wrong)' is a pretty bad drawback. That is pretty much why that option makes me uncomfortable: it does give you better performance, so people may be tempted to use it. Now if it was only a matter of replicating writes only through read-repair/repair, then ok, it's pretty dangerous but it's rather easy to explain/understand the drawback (if you don't lose a disk, you don't lose increments, and you'd better use CL.ALL or have read_repair_chance to 1). But the fact that it doesn't work with bootstrap/move makes me wonder if having the option at all is not making a disservice to users. " IOW, don't be tempted to turn off replicate_on_write. It breaks counters. If you are under capacity at a steady state, increase capacity. =Rob -- =Robert Coli AIM>ALK - rc...@palominodb.com YAHOO - rcoli.palominob SKYPE - rcoli_palominodb
