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Tyler Hobbs commented on CASSANDRA-5519: ---------------------------------------- An initial idea for the implementation: Based on the recent (last 15m?) read rate (reads/sec), periodically down-sample the summary for SSTables which fall below the mean rate. The down-sampling rate could use a sliding scale based on the ratio of the mean to that SSTable's rate. As a example basic implementation, keep X% of the samples, where {{X = max(25, min(100, 100 * (rate / mean_rate)))}}, so the coldest SSTables keep only 25% of the samples in memory. Presenting a way for the user to tune this (other than a simple on/off) is a little trickier. Perhaps make the min (default 25%) adjustable? Or start down-sampling at a configurable point (the default is the mean)? Those could also be automatically adjusted based on memory pressure. > Reduce index summary memory use for cold sstables > ------------------------------------------------- > > Key: CASSANDRA-5519 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5519 > Project: Cassandra > Issue Type: Bug > Components: Core > Reporter: Jonathan Ellis > Priority: Minor > Fix For: 2.0.1 > > -- 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