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https://issues.apache.org/jira/browse/ACCUMULO-3232?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Josh Elser updated ACCUMULO-3232:
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Fix Version/s: (was: 1.7.0)
> Improve consumption of WAL header in partial replication case
> -------------------------------------------------------------
>
> Key: ACCUMULO-3232
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3232
> Project: Accumulo
> Issue Type: Improvement
> Components: replication
> Reporter: Josh Elser
>
> Consider a system that is actively replicating from one instance to another.
> Specifically, assume there is one WAL that is currently being replicated to
> the destination and the source instance is shutdown.
> When the source instance is restarted, it will notice that the WAL has read
> through N {{LogFileKey}}/{{LogFileValue}} pairs (from before it was shutdown)
> and while proceed past these records to get to the data in the file which it
> needs to read.
> We have to re-read each of these pairs from the file because the WAL is an
> append-only structure, and we can't efficiently seek to some point in the
> file, as we wouldn't know how to correlate the byte offset to entries.
> As we read the WAL, in addition (or perhaps instead of) tracking the offset
> in the WAL, it would be good to track the correlation of N bytes read to M
> records consumed which would help us better resume replication.
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