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https://issues.apache.org/jira/browse/HBASE-17852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16344231#comment-16344231
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Josh Elser commented on HBASE-17852:
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{quote}
HBASE-19568 had basically everything that was objected in the reviews here, why
wasn't it brought to the attention of people who raised objections? The
title/reason of that jira reason doesn't matter.
I see it as a really sly move - going behind community and committed changes
which were heavily objected against, by using separate jira.
{quote}
[~appy], let's take a step back, please. I called this out to your attention --
I was under the impression that, based on your earlier comment
([here|https://issues.apache.org/jira/browse/HBASE-17852?focusedCommentId=16327774&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16327774])
that you were OK of this implementation landing in master as-is.
HBASE-19568 was used to commit to master (with what I thought was your
blessing) while we continue to use this JIRA issue to flesh out design because
of all of the discussion that has happened. If I misunderstood you or poorly
asked you the question, let's take that over to HBASE-19568 and get a revert in
place. There was nothing malicious intending to happen here.
> Add Fault tolerance to HBASE-14417 (Support bulk loaded files in incremental
> backup)
> ------------------------------------------------------------------------------------
>
> Key: HBASE-17852
> URL: https://issues.apache.org/jira/browse/HBASE-17852
> Project: HBase
> Issue Type: Sub-task
> Reporter: Vladimir Rodionov
> Assignee: Vladimir Rodionov
> Priority: Major
> Fix For: 3.0.0
>
> Attachments: HBASE-17852-v10.patch, screenshot-1.png
>
>
> Design approach rollback-via-snapshot implemented in this ticket:
> # Before backup create/delete/merge starts we take a snapshot of the backup
> meta-table (backup system table). This procedure is lightweight because meta
> table is small, usually should fit a single region.
> # When operation fails on a server side, we handle this failure by cleaning
> up partial data in backup destination, followed by restoring backup
> meta-table from a snapshot.
> # When operation fails on a client side (abnormal termination, for example),
> next time user will try create/merge/delete he(she) will see error message,
> that system is in inconsistent state and repair is required, he(she) will
> need to run backup repair tool.
> # To avoid multiple writers to the backup system table (backup client and
> BackupObserver's) we introduce small table ONLY to keep listing of bulk
> loaded files. All backup observers will work only with this new tables. The
> reason: in case of a failure during backup create/delete/merge/restore, when
> system performs automatic rollback, some data written by backup observers
> during failed operation may be lost. This is what we try to avoid.
> # Second table keeps only bulk load related references. We do not care about
> consistency of this table, because bulk load is idempotent operation and can
> be repeated after failure. Partially written data in second table does not
> affect on BackupHFileCleaner plugin, because this data (list of bulk loaded
> files) correspond to a files which have not been loaded yet successfully and,
> hence - are not visible to the system
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