Thank you all for the response. I figured out the root cause. I thought all my data was in memtable only but the data was actually being dumped to the disk. That's why I was noticing the drop in throughput.
On Wed, May 24, 2017 at 9:42 AM, daemeon reiydelle <daeme...@gmail.com> wrote: > You speak of increase. Please provide your results. Specific examples, Eg > 25% increase results in n% increase. Also please include number of nodes, > size of total keyspace, rep factor, etc. > > Hopefully this is a 6 node cluster with several hundred gig per keyspace, > not some single node free tier box. > > “All men dream, but not equally. Those who dream by night in the dusty > recesses of their minds wake up in the day to find it was vanity, but the > dreamers of the day are dangerous men, for they may act their dreams with > open eyes, to make it possible.” — T.E. Lawrence > > sent from my mobile > Daemeon Reiydelle > skype daemeon.c.m.reiydelle > USA 415.501.0198 <(415)%20501-0198> > > On May 24, 2017 9:32 AM, "preetika tyagi" <preetikaty...@gmail.com> wrote: > >> Hi, >> >> I'm experimenting with memtable/heap size on my Cassandra server to >> understand how it impacts the latency/throughput for read requests. >> >> I vary heap size (Xms and -Xmx) in jvm.options so memtable will be 1/4 of >> this. When I increase the heap size and hence memtable, I notice the drop >> in throughput and increase in latency. I'm also creating the database such >> that its size doesn't exceed the size of memtable. Therefore, all data >> exist in memtable and I'm not able to reason why bigger size of memtable is >> resulting into higher latency/low throughput. >> >> Since everything is DRAM, shouldn't the throughput/latency remain same in >> all the cases? >> >> Thanks, >> Preetika >> >
