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https://issues.apache.org/jira/browse/HBASE-17852?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16344302#comment-16344302
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stack commented on HBASE-17852:
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{quote}The majority of this code (but not all) went into master in HBASE-19568
btw.
{quote}
The majority of 'HBASE-17852 Add Fault tolerance to HBASE-14417 (Support bulk
loaded files in incremental backup)', a contentious issue, went into another
commit named 'HBASE-19568 Restore of HBase table using incremental backup
doesn't restore rows from an earlier incremental backup' with no outline of
what made it and what did not, and no changeset explaination. There is no
release note. The two JIRAs are not even linked.
{quote}Nope, it turned out that this patch (HBASE-17852) also fixes the issue
raised in HBASE-19568, that is why it was committed (with refactoring code
stripped down). No conspiracy here.
{quote}
But hang on, now the patch here on 'fault tolerance' fixes issues over in the
'restore rows' issue, -HBASE-19568?-
I can see how [~appy] might arrive at his assessment.
On the 'declarations', the first offers options free of context or explanation.
This one I find interesting:
# Use procedure framework: Short answer - no. I will wait until procv2
becomes more mature and robust. I do not want to build new feature on a
foundation of a new feature. Too risky in my opinion. NO
....when we are talking about a hbase3 (possibly) feature and when there is no
alternative.
Anyway, keeping it short.
> 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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