Hi Peter, Thanks for the response. I haven't explictly set a value for the memtable_flush_after_mins parameter. Looks like the default is 60minutes. I will try to play around this value to see if that fixes things. Thanks again!
On Thu, May 12, 2011 at 11:41 AM, Peter Schuller < peter.schul...@infidyne.com> wrote: > > I understand that cassandra periodically cleans up the commitlog > directories > > by generating sstables in datadir. Is there any way to speed up this > > movement from commitog to datadir? > > commitlog_rotation_threshold_in_mb could cause problems if it was set > very very high, but with the default of 128mb it should not be an > issue. > > I suspect the most likely reason is that you have a column family > whose memtable flush settings are extreme. A commit log segment cannot > be removed until the corresponding data has been flushed to an > sstable. For high-throughput memtables where you flush regularly this > should happen often. For idle or almost idle memtables you may be > waiting on the timeout criteria to trigger. So in general, having a > memtable with a long expiry time will have the potential to generate > commit logs of whatever size is implied by the write traffic during > that periods. > > The memtable setting in question is the "memtable_flush_after" > setting. Do you have that set to something very high on one of your > column families? > > You can use "describe keyspace name_of_keyspace" in cassandra-cli to > check current settings. > > -- > / Peter Schuller >
