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https://issues.apache.org/jira/browse/HBASE-10247?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14094632#comment-14094632
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Andrew Purtell commented on HBASE-10247:
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bq. Either we accept out of order timestamps at the slave (when we use the 
timestamps of the primary)

Yes, but this can be acceptable for DR use cases. Also, if backups are handled 
through some other means, such as snapshots+copy and replication is not active, 
having an option to restrict timestamps to server generated stamps can still be 
useful. Until we're bridging clusters with Raft etc.

> Client promises about timestamps
> --------------------------------
>
>                 Key: HBASE-10247
>                 URL: https://issues.apache.org/jira/browse/HBASE-10247
>             Project: HBase
>          Issue Type: Brainstorming
>            Reporter: Lars Hofhansl
>            Priority: Minor
>             Fix For: 0.99.0, 2.0.0
>
>         Attachments: 10247-do-not-try-may-eat-your-first-born-v2.txt, 
> 10247.txt
>
>
> This is to start a discussion about timestamp promises declared per table of 
> CF.
> For example if a client promises only monotonically increasing timestamps (or 
> no custom set timestamps) and VERSIONS=1, we can aggressively and easily 
> remove old versions of the same row/fam/col from the memstore before we 
> flush, just by supplying a comparator that ignores the timestamp (i.e. two KV 
> just differing by TS would be considered equal).
> That would increase the performance of counters significantly.



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