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Hudson commented on CASSANDRA-1469: ----------------------------------- Integrated in Cassandra #536 (See [https://hudson.apache.org/hudson/job/Cassandra/536/]) Adaptively set the heap size and memtable thresholds at runtime. Patch by brandonwilliams, reviewed by jbellis for CASSANDRA-1469 > adaptive default heap size > -------------------------- > > Key: CASSANDRA-1469 > URL: https://issues.apache.org/jira/browse/CASSANDRA-1469 > Project: Cassandra > Issue Type: New Feature > Components: Packaging > Reporter: Jonathan Ellis > Assignee: Brandon Williams > Fix For: 0.7.0 > > Attachments: 0001_adaptively_determine_heap_size.txt, > 0002_determine_memtable_thresholds_at_runtime.txt > > > Cassandra comes out of the box with very conservative defaults, especially in > -Xmx and memtable sizes, which leads to complaints of poor performance or > even OOM conditions under heavy load. But changing these to be aggressive > can cause the same problem: most servers enable swap out of the box, so > asking for a 4GB or 8GB heap could allocate happily but also cause problems > when it starts paging. > Proposed solution is to update the start script to set Xmx to half of system > ram ("free -m | awk '/Mem:/ {print $2}'"). Memtable defaults will have to be > handled by Java, but we can do that based on heap size (Runtime.maxMemory). > An alternative suggestion was to provide "small", "medium", "large" > configurations, but this plays poorly with rpm and deb packages. I think the > adaptive approach is more promising. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.