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https://issues.apache.org/jira/browse/HBASE-2834?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrew Purtell resolved HBASE-2834.
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Resolution: Duplicate
> Deferred deletes
> ----------------
>
> Key: HBASE-2834
> URL: https://issues.apache.org/jira/browse/HBASE-2834
> Project: HBase
> Issue Type: New Feature
> Reporter: Andrew Purtell
>
> Tangentally mentioned in a blog post, James Hamilton talks about deferred
> deletes:
> {quote}
> If you have an application error, administrative error, or database
> implementation bug that losses data, then it is simply gone unless you have
> an offline copy. This, by the way, is why I'm a big fan of deferred delete.
> This is a technique where deleted items are marked as deleted but not garbage
> collected until some days or preferably weeks later. Deferred delete is not
> full protection but it has saved my butt more than once and I'm a believer.
> See On Designing and Deploying Internet-Scale Services
> (http://mvdirona.com/jrh/talksAndPapers/JamesRH_Lisa.pdf) for more detail.
> {quote}
> (See
> http://perspectives.mvdirona.com/2010/04/07/StonebrakerOnCAPTheoremAndDatabases.aspx)
> Because deletes -- at least, after the initial write has been flushed from
> memstore -- are tombstones, deferred delete in HBase could be supported if
> somehow tombstones could be invalidated, an undelete operation in effect.
> This could be accomplished by adding support for tombstones for deletes.
> Would complicate major compaction but otherwise not touch much. A typical use
> case might be "resurrect any data deleted from _ts1_ to _ts2_ ", a period of
> 4 hours when an application error was operative. In this case a new write
> would be issued to the table that is a tombstone covering any deletes over
> that period of time. Users would defer major compactions until safe
> checkpoint periods.
> Such guarantees could optionally be extended to the memstoe by using
> tombstones there as well. But it would probably be sufficient to provide
> guidance that forcing a flush is necessary to insure edits are persisted in
> a way that allows for undeletion.
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