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https://issues.apache.org/jira/browse/PHOENIX-2154?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14700735#comment-14700735
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James Taylor commented on PHOENIX-2154:
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It's single reducer because the index table is a new/empty table and thus has a
single region. We can't know the split points in advance as there's no
correlation between the data table split points and the index split plints.
It'd be good to make it configurable to still use the HFile path, as for an
index rebuild, we would have multiple, existing regions so perf should improve.
We should perf test the rebuild scenario too.
> Failure of one mapper should not affect other mappers in MR index build
> -----------------------------------------------------------------------
>
> Key: PHOENIX-2154
> URL: https://issues.apache.org/jira/browse/PHOENIX-2154
> Project: Phoenix
> Issue Type: Bug
> Reporter: James Taylor
> Attachments: IndexTool.java
>
>
> Once a mapper in the MR index job succeeds, it should not need to be re-done
> in the event of the failure of one of the other mappers. The initial
> population of an index is based on a snapshot in time, so new rows getting
> *after* the index build has started and/or failed do not impact it.
> Also, there's a 1:1 correspondence between index rows and table rows, so
> there's really no need to dedup. However, the index rows will have a
> different row key than the data table, so I'm not sure how the HFiles are
> split. Will they potentially overlap and is this an issue?
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