We are planning to upgrade soon. But in the meantime, I wanted to see if we can tweak certain things.
-Rajesh On Wed, Nov 5, 2014 at 3:10 PM, Robert Coli <rc...@eventbrite.com> wrote: > On Tue, Nov 4, 2014 at 8:51 PM, Raj N <raj.cassan...@gmail.com> wrote: > >> Is there a good formula to calculate heap utilization in Cassandra >> pre-1.1, specifically 1.0.10. We are seeing gc pressure on our nodes. And I >> am trying to estimate what could be causing this? Using node tool info my >> steady state heap is at about 10GB. XMX is 12G. >> > > Basically, no. If you really want to know, take a heap dump and load it > into Eclipse Memory Analyzer. > > >> I have 4.5 GB of bloom filters which I can derive looking at cfstats >> > > This is a *very* large percentage of your total heap, and is probably the > lever you have most influence on pulling. > > >> I have negligible row caching. >> > > Row caching is generally not advised in that era, especially with heap > pressure. > > >> I have key caching enabled on my cfs. I couldn't find an easy way to >> estimate how much this is using, but I tried to invalidate the key cache >> and I got 1.3 GB back. >> > > Key caching is generally advisable, but 1.3GB is a lot of key cache.. > > >> That still only adds up to 5.8 GB. I know there is index sampling going >> on as well. I have around 800 million rows. Is there a way to estimate how >> much space this would add up to? >> > > Plenty. You should reduce your bloom filter size, or upgrade to a version > of Cassandra that moves stuff off the heap. > > =Rob > http://twitter.com/rcolidba > > >
