Peaks may be occurring during compaction, when Sstable files are memmapped. If so: Upgrading to C* 1.2 may bring some relief: You can trigger minor compaction on an individual SStable file when the percentage of tombstones in that Sstable crosses a user-defined threshold. (Aaron, can you confirm?)
From: Alain RODRIGUEZ [mailto:arodr...@gmail.com] Sent: Wednesday, March 13, 2013 7:11 PM To: user@cassandra.apache.org Subject: About the heap Hi, I would like to know everything that is in the heap. We are here speaking of C*1.1.6 Theory : - Memtable (1024 MB) - Key Cache (100 MB) - Row Cache (disabled, and serialized with JNA activated anyway, so should be off-heap) - BloomFilters (about 1,03 GB - from cfstats, adding all the "Bloom Filter Space Used" and considering they are showed in Bytes - 1103765112) - Anything else ? So my heap should be fluctuating between 1,15 GB and 2.15 GB and growing slowly (from the new BF of my new data). My heap is actually changing from 3-4 GB to 6 GB and sometimes growing to the max 8 GB (crashing the node). Because of this I have an unstable cluster and have no other choice than use Amazon EC2 xLarge instances when we would rather use twice more EC2 Large nodes. What am I missing ? Practice : Is there a way not inducing any load and easy to do to dump the heap to analyse it with MAT (or anything else that you could advice) ? Alain _______________________________________________ This message may contain information that is confidential or privileged. If you are not an intended recipient of this message, please delete it and any attachments, and notify the sender that you have received it in error. Unless specifically stated in the message or otherwise indicated, you may not uplicate, redistribute or forward this message or any portion thereof, including any attachments, by any means to any other person, including any retail investor or customer. This message is not a recommendation, advice, offer or solicitation, to buy/sell any product or service, and is not an official confirmation of any transaction. Any opinions presented are solely those of the author and do not necessarily represent those of Barclays. This message is subject to terms available at: www.barclays.com/emaildisclaimer and, if received from Barclays' Sales or Trading desk, the terms available at: www.barclays.com/salesandtradingdisclaimer/. By messaging with Barclays you consent to the foregoing. Barclays Bank PLC is a company registered in England (number 1026167) with its registered office at 1 Churchill Place, London, E14 5HP. This email may relate to or be sent from other members of the Barclays group. _______________________________________________
