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Chris Goffinet commented on CASSANDRA-1902: ------------------------------------------- Peter, Just to be clear, I know about the fsync + dirty buffers issue. My patch made sure to fsync data as it flushes. And this isn't related to what I was seeing, because I was watching the pages of SSTables that were all cold, slowly become hot during compaction. > Migrate cached pages during compaction > --------------------------------------- > > Key: CASSANDRA-1902 > URL: https://issues.apache.org/jira/browse/CASSANDRA-1902 > Project: Cassandra > Issue Type: Improvement > Components: Core > Affects Versions: 0.7.1 > Reporter: T Jake Luciani > Assignee: Pavel Yaskevich > Fix For: 1.0 > > Attachments: > 0001-CASSANDRA-1902-cache-migration-impl-with-config-option.txt, > 1902-BufferedSegmentedFile-logandsleep.txt, 1902-formatted.txt, > 1902-per-column-migration-rebase2.txt, 1902-per-column-migration.txt, > CASSANDRA-1902-v10-trunk-rebased.patch, CASSANDRA-1902-v3.patch, > CASSANDRA-1902-v4.patch, CASSANDRA-1902-v5.patch, CASSANDRA-1902-v6.patch, > CASSANDRA-1902-v7.patch, CASSANDRA-1902-v8.patch, > CASSANDRA-1902-v9-trunk-rebased.patch, > CASSANDRA-1902-v9-trunk-with-jmx.patch, CASSANDRA-1902-v9-trunk.patch, > CASSANDRA-1902-v9.patch > > Original Estimate: 32h > Time Spent: 56h > Remaining Estimate: 0h > > Post CASSANDRA-1470 there is an opportunity to migrate cached pages from a > pre-compacted CF during the compaction process. This is now important since > CASSANDRA-1470 caches effectively nothing. > For example an active CF being compacted hurts reads since nothing is cached > in the new SSTable. > The purpose of this ticket then is to make sure SOME data is cached from > active CFs. This can be done my monitoring which Old SSTables are in the page > cache and caching active rows in the New SStable. > A simpler yet similar approach is described here: > http://insights.oetiker.ch/linux/fadvise/ -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira