> It has 13.7million keys How big is your Row Keys? Current calculation (in 1.1) assumes that the average size of the Entry<RowKey, Long> in the keycache is 16 bytes.
One thing which you can do to get out this issue is to reduce the Keycache to a low enough to get the server started or increase the Heap to hold all the objects. (If you are using the visualVM try to see the object counts). Regards, </VJ> On Thu, Jun 28, 2012 at 3:40 PM, Gurpreet Singh <gurpreet.si...@gmail.com>wrote: > Vijay, > I am running into an issue right now, not sure if its related to this one. > > My cassandra 1.1 was running fine for a week, and the key cache size (as > checked by jconsole) increased to almost 650 mb. It has 13.7million keys. I > have set key_cache_size_in_mb to 800 mb. I checked the heap size, and it > was at 6 gigs. All good! > However, when i try to restart cassandra, it is unable to start now. > Before i shut it down, it seemed fine at 6 gigs, which means its able to > handle the memory requirements just fine. However it is not able to start > up anymore with the same key cache. jconsole says that the heap is full. > > Thanks > /G > > > On Thu, Jun 28, 2012 at 12:22 PM, Vijay <vijay2...@gmail.com> wrote: > >> 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 >>>> >>> >>> >> >
