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https://issues.apache.org/jira/browse/ACCUMULO-3423?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14313013#comment-14313013
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Eric Newton commented on ACCUMULO-3423:
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Have all the ITs working now, except those related to replication. I talked to
[~elserj] about the changes necessary.
* the tablet server or master should inform replication when a WAL is closed
* the GC should defer deleting WALs in use by replication
* the tablet server should just let the GC clean up WALs
> speed up WAL roll-overs
> -----------------------
>
> Key: ACCUMULO-3423
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3423
> Project: Accumulo
> Issue Type: Bug
> Components: master, tserver
> Reporter: Eric Newton
> Assignee: Eric Newton
>
> After reading the proposal on HBASE-10278, I realized there are many ways to
> make the Accumulo WAL roll-over faster.
> # Open two WALogs, but use only one until it reaches the WALog roll-over size
> # Rollover consists only of swapping the writers
> # WALog roll consists of the final close, which can happen in parallel
> # Don't mark the tablets with log entries: they are already marked with the
> tserver
> # The tserver can make notes about the logs-in-use in the metadata table(s)
> as part of opening the log.
> # The master can copy the log entries to tablets while unassigning them,
> piggybacking on the unassigment mutation.
> # Tablet servers can remove their current log entries from the metadata
> tables when they have no tablets using them.
> There are two issues:
> # tablets will have an empty file in recovery, nearly all the time, but the
> recovery code already handles that case.
> # presently, a tablet doesn't have a marker for a log it did not use. Many
> more tablets will attempt to recover when it is unnecessary.
> This would also address ACCUMULO-2889.
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