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Pavel Yaskevich commented on CASSANDRA-4937: -------------------------------------------- There is only once place where shouldPreheatPageCache() is used (CompactionTask:233) it shouldn't anyhow affect key cache from being populated, that only could be done by getPreheatKeyCache() flag in config. > CRAR improvements (object cache + CompressionMetadata chunk offset storage > moved off-heap). > ------------------------------------------------------------------------------------------- > > Key: CASSANDRA-4937 > URL: https://issues.apache.org/jira/browse/CASSANDRA-4937 > Project: Cassandra > Issue Type: Improvement > Reporter: Pavel Yaskevich > Assignee: Pavel Yaskevich > Labels: core > Fix For: 1.2.4 > > Attachments: 4937-v3.txt, CASSANDRA-4937.patch, > CASSANDRA-4937-trunk.patch, CASSANDRA-4937-v4.patch > > > After good amount of testing on one of the clusters it was found that in > order to improve read latency we need to minimize allocation rate that > compression involves, that minimizes GC (as well as heap usage) and > substantially decreases latency on read heavy workloads. > I have also discovered that RAR skip cache harms performance in situation > when reads are done in parallel with compaction working with relatively big > SSTable files (few GB and more). The attached patch removes possibility to > skip cache from compressed files (I can also add changes to RAR to remove > skip cache functionality as a separate patch). -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira