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https://issues.apache.org/jira/browse/CASSANDRA-1967?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13422628#comment-13422628
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Jonathan Ellis commented on CASSANDRA-1967:
-------------------------------------------
You're barking up the wrong tree by blaming flush. To the degree that
compaction is a problem (and on a properly tuned system it shouldn't be), we
can simply extend the five minute delay on autocompaction to these flushes as
well.
> commit log replay shouldn't end with a flush
> --------------------------------------------
>
> Key: CASSANDRA-1967
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1967
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Affects Versions: 0.3
> Reporter: Robert Coli
> Priority: Minor
>
> (Apologies in advance if there is some very compelling reason to flush after
> replay, of which I am not currently aware. ;D)
> Currently, when a node restarts, the following sequence occurs :
> a) commitlog is replayed
> b) any memtables resulting from a) are flushed
> c) a new commitlog is opened, new memtables are switched in
> ... (other stuff happens)
> d) node starts taking traffic
> This has side effects, perhaps most seriously the potential of triggering
> compaction. As a node is likely to struggle performance-wise after
> restarting, triggering compaction at that time seems like something we might
> wish to avoid.
> I propose that the sequence be :
> a) commitlog is replayed
> b) a new commitlog is opened, new memtables are switched in
> ... (other stuff happens)
> c) node starts taking traffic
> Looking through the relevant code, the only code that appears to depend on
> this flush is at
> src/java/org/apache/cassandra/db/commitlog/CommitLog.java:112 :
> "
> // all old segments are recovered and deleted before CommitLog is
> instantiated.
> // All we need to do is create a new one.
> segments.add(new CommitLogSegment());
> "
> Presumably this code would have to be refactored to be aware of the currently
> open commitlog.
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