in 1.1 we dont calculate the Key size accurately, hence we have the fix in https://issues.apache.org/jira/browse/CASSANDRA-4315
Regards, </VJ> On Thu, Jun 28, 2012 at 11:25 AM, Gurpreet Singh <gurpreet.si...@gmail.com>wrote: > anyone have an explanation for this? > This kinda screws up memory calculations. > > /G > > On Mon, Jun 25, 2012 at 5:50 PM, Gurpreet Singh > <gurpreet.si...@gmail.com>wrote: > >> Hi, >> I have a question about cassandra 1.1 >> >> Just wanted to confirm if key_cache_size_in_mb is the maximum amount of >> memory that key cache will use in memory? If not, what is it? >> >> My observations: >> With key cache disabled, I started cassandra. I invoked Full GC through >> jconsole a couple of times just to make sure that memory is freed up. >> Total heap memory in use is 2.2 gigs. I have almost 550 million keys, so >> this looked reasonable as the bloom filter itself is around 1 gig. >> >> I enabled key cache again by making key_cache_size_in_mb to a value 800. >> This would lead cassandra to load a previously saved key cache file of size >> 98 mb on disk. I restarted cassandra again. This time the heap size >> increased to 4.2 gigs. I checked the cache sizing in jconsole. >> >> KeyCacheCapacityInMb: 799 >> KeyCacheSize: 410,316,048 >> >> This says that the key cache size is 410 mb. However the increase in the >> heap is 2 gigs. Doesnt add up!! >> >> Can anyone explain this? >> Thanks >> Gurpreet >> > >
