[
https://issues.apache.org/jira/browse/CASSANDRA-3411?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13147516#comment-13147516
]
Rick Branson commented on CASSANDRA-3411:
-----------------------------------------
Recycling the replayed segments is a good idea. Very elegant.
I wasn't quite sure how strict the cap limit was -- 004 tries to hit the cap
with a "best effort" and doesn't really treat it as a hard limit. If it's
strict-in-bold it definitely needs to be reworked. CommitLog should detect a
potential overflow before it even allows the write to take place and "stop the
world" to perform a flush.
submitCreateFreshSegment was an oversight for sure, a refactor relic.
CLS.recycle() returning a new CLS is more of a preference than anything else --
I tend to reach for more immutability when it doesn't hurt, and overall it
seemed to be a cleaner approach than reseting the state.
You have a good point about the order of shutdownBlocking, and actually, is the
sync() even necessary here or is it cargo cult?
> 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,
> 003-pre-allocated-recycled-commitlog-segment-files-CASSANDRA-3411.patch,
> 004-pre-allocated-recycled-commitlog-segment-files-CASSANDRA-3411.patch,
> 3411-cleaned.txt, 3411-v5.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
