Thanks for your response I think the reference you are talking about is http://wiki.apache.org/cassandra/MemtableSSTable Regards, Anurag
On Sun, May 8, 2011 at 11:01 AM, Peter Schuller <peter.schul...@infidyne.com > wrote: > > I stop my cassandra node and restarted it,this start and stop > > resulted in decrease in the space used by cassandra by 20%. > > I am not sure what is happening?Can Anyone please shower some light on > this > > Probably because unused sstables were deleted on start-up that were > otherwise not used, and waiting on full GC to be removed. Check > system.log for "deleted sstable" messages. I didn't find a wiki ref > right now, but in short cassandra uses weak references to discover > when an sstable is guaranteed to no longer be used, in order to > perform removals of the actual sstable files. This can lead to a delay > of sstable removal which will vary with whatever else is happening > (the more busy the node, the more often a concurrent mark/sweep gc > phase is triggered, and the more frequently obsolete sstables are > deleted). > > -- > / Peter Schuller >
