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HBASE-8770 deletes and puts with the same ts should be resolved according to mvcc/seqNum

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Michael Stack 2018-03-01 23:51:08 -08:00
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@ -343,6 +343,7 @@ In particular:
Below we describe how the version dimension in HBase currently works. Below we describe how the version dimension in HBase currently works.
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. 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.
It has more detail on versioning than is provided here. It has more detail on versioning than is provided here.
As of this writing, the limitation _Overwriting values at existing timestamps_ mentioned in the article no longer holds in HBase. As of this writing, the limitation _Overwriting values at existing timestamps_ mentioned in the article no longer holds in HBase.
This section is basically a synopsis of this article by Bruno Dumon. This section is basically a synopsis of this article by Bruno Dumon.
@ -503,8 +504,42 @@ Otherwise, a delete marker with a timestamp in the future is kept until the majo
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]. 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].
The change has been backported to HBase 0.94 and newer branches. The change has been backported to HBase 0.94 and newer branches.
[[new.version.behavior]]
=== Optional New Version and Delete behavior in HBase-2.0.0
In `hbase-2.0.0`, the operator can specify an alternate version and
delete treatment by setting the column descriptor property
`NEW_VERSION_BEHAVIOR` to true (To set a property on a column family
descriptor, you must first disable the table and then alter the
column family descriptor; see <<cf.keep.deleted>> for an example
of editing an attribute on a column family descriptor).
The 'new version behavior', undoes the limitations listed below
whereby a `Delete` ALWAYS overshadows a `Put` if at the same
location -- i.e. same row, column family, qualifier and timestamp
-- regardless of which arrived first. Version accounting is also
changed as deleted versions are considered toward total version count.
This is done to ensure results are not changed should a major
compaction intercede. See `HBASE-15968` and linked issues for
discussion.
Running with this new configuration currently costs; we factor
the Cell MVCC on every compare so we burn more CPU. The slow
down will depend. In testing we've seen between 0% and 25%
degradation.
If replicating, it is advised that you run with the new
serial replication feature (See `HBASE-9465`; the serial
replication feature did NOT make it into `hbase-2.0.0` but
should arrive in a subsequent hbase-2.x release) as now
the order in which Mutations arrive is a factor.
=== Current Limitations === Current Limitations
The below limitations are addressed in hbase-2.0.0. See
the section above, <<new.version.behavior>>.
==== Deletes mask Puts ==== Deletes mask Puts
Deletes mask puts, even puts that happened after the delete was entered. Deletes mask puts, even puts that happened after the delete was entered.