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https://issues.apache.org/jira/browse/HBASE-493?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrei Dragomir updated HBASE-493:
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Affects Version/s: 0.21.0
Status: Patch Available (was: Reopened)
I have a patch related to this.
Basically, it's working just like HTable.checkAndPut, except that it checks
timestamp, not value. There is still a lock on the row, but it's done in the
HRegion object, close to the data. We could make it without, but I don't see
how we could guarantee that it works ok.
> Write-If-Not-Modified-Since support
> -----------------------------------
>
> Key: HBASE-493
> URL: https://issues.apache.org/jira/browse/HBASE-493
> Project: Hadoop HBase
> Issue Type: New Feature
> Components: client, io, regionserver
> Affects Versions: 0.21.0
> Reporter: Chris Richard
> Priority: Minor
> Fix For: 0.21.0
>
>
> Write-If-Not-Modified-Since for optimistic concurrency control:
> Client retrieves cell (or row) and stores timestamp.
> Client writes to same cell (or row) and passes timestamp.
> If the cell's (or row's) latest timestamp matches the passed timestamp, the
> write succeeds. If the timestamps do not match, the write fails and the
> client is notified. The client must re-retrieve the cell/row to get the
> latest timestamp before attempting to write back.
> This behavior would be optional, if the client doesn't pass a timestamp to
> the write method, no modified check would be enforced.
> Note: blocked behind HBASE-489 due to requirement that client be able to
> access timestamp values.
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