What is your row cache hit rate? By "still slow" do you mean "no change observed" or "faster but not fast enough?"
On Tue, Mar 30, 2010 at 10:47 PM, James Golick <jamesgol...@gmail.com> wrote: > We are starting to use cassandra to power our activity feed. The way we > organize our data is simple. "Event"s live in a CF called Events and are > keyed by a UUID. The timelines themselves live in a CF called Timelines, > which is keyed by user id (i.e. "1229") and contains a event uuids as column > names (sorted by TimeUUIDType). > To load a feed, we get a slice of the timeline CF for that user, then > multiget all of the corresponding events. > Loading the slice of the timeline is reasonably fast at 4-6ms. But, > multigetting the events is terribly slow - on the order of 35-100ms. > To alleviate the problem, we write events through to memcached and use a > memcached multiget in front of the cassandra multiget. We have enough cache > space to get upwards of a 99% hit rate, which makes loading the events > extremely fast, but it would be nice to make use of the 24GB of memory in > our cassandra nodes. > We're on 0.6, and I've enabled the row cache. It seems to have data in it, > but it's still slow. > So, am I doing something wrong, or is this the expected perf? > - James
