HBASE-8770 deletes and puts with the same ts should be resolved according to mvcc/seqNum
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@ -343,6 +343,7 @@ In particular:
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Below we describe how the version dimension in HBase currently works.
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See link:https://issues.apache.org/jira/browse/HBASE-2406[HBASE-2406] for discussion of HBase versions. link:https://www.ngdata.com/bending-time-in-hbase/[Bending time in HBase] makes for a good read on the version, or time, dimension in HBase.
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It has more detail on versioning than is provided here.
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As of this writing, the limitation _Overwriting values at existing timestamps_ mentioned in the article no longer holds in HBase.
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This section is basically a synopsis of this article by Bruno Dumon.
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@ -503,8 +504,42 @@ Otherwise, a delete marker with a timestamp in the future is kept until the majo
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NOTE: This behavior represents a fix for an unexpected change that was introduced in HBase 0.94, and was fixed in link:https://issues.apache.org/jira/browse/HBASE-10118[HBASE-10118].
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The change has been backported to HBase 0.94 and newer branches.
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[[new.version.behavior]]
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=== Optional New Version and Delete behavior in HBase-2.0.0
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In `hbase-2.0.0`, the operator can specify an alternate version and
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delete treatment by setting the column descriptor property
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`NEW_VERSION_BEHAVIOR` to true (To set a property on a column family
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descriptor, you must first disable the table and then alter the
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column family descriptor; see <<cf.keep.deleted>> for an example
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of editing an attribute on a column family descriptor).
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The 'new version behavior', undoes the limitations listed below
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whereby a `Delete` ALWAYS overshadows a `Put` if at the same
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location -- i.e. same row, column family, qualifier and timestamp
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-- regardless of which arrived first. Version accounting is also
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changed as deleted versions are considered toward total version count.
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This is done to ensure results are not changed should a major
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compaction intercede. See `HBASE-15968` and linked issues for
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discussion.
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Running with this new configuration currently costs; we factor
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the Cell MVCC on every compare so we burn more CPU. The slow
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down will depend. In testing we've seen between 0% and 25%
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degradation.
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If replicating, it is advised that you run with the new
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serial replication feature (See `HBASE-9465`; the serial
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replication feature did NOT make it into `hbase-2.0.0` but
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should arrive in a subsequent hbase-2.x release) as now
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the order in which Mutations arrive is a factor.
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=== Current Limitations
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The below limitations are addressed in hbase-2.0.0. See
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the section above, <<new.version.behavior>>.
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==== Deletes mask Puts
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Deletes mask puts, even puts that happened after the delete was entered.
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