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https://issues.apache.org/jira/browse/HBASE-8721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13689435#comment-13689435
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Lars Hofhansl commented on HBASE-8721:
--------------------------------------

KEEP_DELETED_CELLS would still work fine, but their main goal is to allow 
correct point-in-time-queries, which among others is important for consistent 
backups.

Regarding all the points above. Let's please not go overboard. Now we're 
extending this to Puts as well, and are saying that a Put that hits the 
RegionServer later should be considered newer even if its TS is old, this opens 
another can of worms.

It is unlikely that this will be changed as you have to a find committers to +1 
this. All we got up to this points are a -1 unless it is configurable and a 
couple of -0s.

                
> Deletes can mask puts that happen after the delete
> --------------------------------------------------
>
>                 Key: HBASE-8721
>                 URL: https://issues.apache.org/jira/browse/HBASE-8721
>             Project: HBase
>          Issue Type: Improvement
>          Components: regionserver
>            Reporter: Feng Honghua
>         Attachments: HBASE-8721-0.94-V0.patch
>
>
> this fix aims for bug mentioned in http://hbase.apache.org/book.html 5.8.2.1:
> "Deletes mask puts, even puts that happened after the delete was entered. 
> Remember that a delete writes a tombstone, which only disappears after then 
> next major compaction has run. Suppose you do a delete of everything <= T. 
> After this you do a new put with a timestamp <= T. This put, even if it 
> happened after the delete, will be masked by the delete tombstone. Performing 
> the put will not fail, but when you do a get you will notice the put did have 
> no effect. It will start working again after the major compaction has run. 
> These issues should not be a problem if you use always-increasing versions 
> for new puts to a row. But they can occur even if you do not care about time: 
> just do delete and put immediately after each other, and there is some chance 
> they happen within the same millisecond."

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