[ https://issues.apache.org/jira/browse/CASSANDRA-3411?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jonathan Ellis updated CASSANDRA-3411: -------------------------------------- Attachment: 3411-cleaned.txt attaching -cleaned, which is mostly undoing some renaming that obscured the real changes here. I think there's some work to do around the commitlog preallocation: - Seems like we should try to keep an extra segment ready, so that after we exhaust our preallocated quota we don't block for each new segment - segments to keep around should be our high water mark of active - if we record that high water mark in the system table, that feels like a better way of self-tuning to me than exposing the preallocation count as a tuneable - segment allocation should be done off of the CLExecutor thread. if we make "segments" just "inactive segments" instead of "all segments" then we can make it into a blocking queue for that purpose > Pre-allocated, Recycled Commitlog Segment Files > ----------------------------------------------- > > Key: CASSANDRA-3411 > URL: https://issues.apache.org/jira/browse/CASSANDRA-3411 > Project: Cassandra > Issue Type: Improvement > Components: Core > Reporter: Rick Branson > Priority: Minor > Attachments: > 001-pre-allocated-recycled-commitlog-segment-files-CASSANDRA-3411.patch, > 3411-cleaned.txt > > > An approach for improving commitlog performance is to pre-allocate the full > 128MB segment files and reuse them once all the mutations have been flushed. > Pre-allocation allows writes to be performed without modifying the file size > metadata, and should (in theory) allow the filesystem to allocate a > contiguous block of space for the file. Recycling the segment files prevents > the overhead of pre-allocation from impacting overall performance. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira