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https://issues.apache.org/jira/browse/HBASE-5604?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13234485#comment-13234485
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Lars Hofhansl commented on HBASE-5604:
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This is a part of HBase I not that familiar with.
Why is this in principle different from ImportTsv?
I guess it is because each mapper can encounter WALEdits for many tables in the
HLog file(s) that it works on...?
In the end, though, it would a reducer writing the HFiles, so the distribution
of HLogs to mappers should not matter. I think.
Hmm... Maybe this is only useful when we have a *lot* of logs to replay such as
in a point in time recovery scenario using HLogs.
Or maybe there would be no advantage here turning this in an M/R job, but maybe
it should just be a standalone client...?
> HLog replay tool that generates HFiles for use by LoadIncrementalHFiles.
> ------------------------------------------------------------------------
>
> Key: HBASE-5604
> URL: https://issues.apache.org/jira/browse/HBASE-5604
> Project: HBase
> Issue Type: New Feature
> Reporter: Lars Hofhansl
>
> Just an idea I had. Might be useful for restore of a backup using the HLogs.
> This could an M/R (with a mapper per HLog file).
> The tool would get a timerange and a (set of) table(s). We'd pick the right
> HLogs based on time before the M/R job is started and then have a mapper per
> HLog file.
> The mapper would then go through the HLog, filter all WALEdits that didn't
> fit into the time range or are not any of the tables and then uses
> HFileOutputFormat to generate HFiles.
> Would need to indicate the splits we want, probably from a live table.
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