What operation are you calling ? Are you trying to read the entire row back?
How many SSTables do you have for the CF? Does your data have a lot of overwrites ? Have you modified the default compaction settings ? Do you have row cache enabled ? How long does the second request take ? Can you use JConsole to check the read latency for the CF? Sorry for all the questions, the answer to your initial question is "mmm, that does not sound right. It will depend on...." Aaron On 5 Feb 2011, at 08:13, Dan Kuebrich wrote: > Hi all, > > It often takes more than two seconds to load: > > - one row of ~450 events comprising ~600k > - cluster size of 1 > - client is pycassa 1.04 > - timeout on recv > - cold read (I believe) > - load generally < 0.5 on a 4-core machine, 2 EC2 instance store drives for > cassandra > - cpu wait generally < 1% > > Often the following sequence occurs: > > 1. First attempt times out after 2 sec > 2. Second attempt loads fine on immediate retry > > So, I assume it's an issue about cache miss and going to disk. Is 2 seconds > the normal "I went to disk" latency for cassandra? What should we look to > tune, if anything? I don't think keeping everything in-memory is an option > for us given dataset size and access pattern (hot set is stuff being > currently written, stuff being accessed is likely to be older). > > I didn't notice this problem with cassandra 0.6.8 and pycassa 0.3. > > Thanks, > dan
