Take a look at https://issues.apache.org/jira/browse/CASSANDRA-5661
On Mon, Jul 15, 2013 at 4:18 AM, sulong <sulong1...@gmail.com> wrote: > Thanks for your help. Yes, I will try to increase the sstable size. I hope > it can save me. > > 9000 SSTableReader x 10 RandomAccessReader x 64Kb = 5.6G memory. If there > is only one RandomAccessReader, the memory will be 9000 * 1 * 64Kb = 0.56G > . Looks great. But I think it must be reasonable to recycle the > RandomAccessReader. > > > On Mon, Jul 15, 2013 at 4:02 PM, Janne Jalkanen > <janne.jalka...@ecyrd.com>wrote: > >> >> I had exactly the same problem, so I increased the sstable size (from 5 >> to 50 MB - the default 5MB is most certainly too low for serious usecases). >> Now the number of SSTableReader objects is manageable, and my heap is >> happier. >> >> Note that for immediate effect I stopped the node, removed the *.json >> files and restarted - which put all SSTables to L0, which meant a weekend >> full of compactions… Would be really cool if there was a way to >> automatically drop all LCS SSTables one level down to make them compact >> earlier without avoiding the >> "OMG-must-compact-everything-aargh-my-L0-is-full" -effect of removing the >> JSON file. >> >> /Janne >> >> On 15 Jul 2013, at 10:48, sulong <sulong1...@gmail.com> wrote: >> >> > Why does cassandra PoolingSegmentedFile recycle the RandomAccessReader? >> The RandomAccessReader objects consums too much memory. >> > >> > I have a cluster of 4 nodes. Every node's cassandra jvm has 8G heap. >> The cassandra's memory is full after about one month, so I have to restart >> the 4 nodes every month. >> > >> > I have 100G data on every node, with LevedCompactionStrategy and 10M >> sstable size, so there are more than 10000 sstable files. By looking >> through the heap dump file, I see there are more than 9000 SSTableReader >> objects in memory, which references lots of RandomAccessReader objects. >> The memory is consumed by these RandomAccessReader objects. >> > >> > I see the PoolingSegementedFile has a recycle method, which puts the >> RandomAccessReader to a queue. Looks like the Queue always grow until the >> sstable is compacted. Is there any way to stop the RandomAccessReader >> recycling? Or, set a limit to the recycled RandomAccessReader's number? >> > >> > >> >> > -- http://twitter.com/tjake
