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Re: CheckAndAppend Feature
Hi Lars:

This helps a lot! Thanks!

Best Regards,


Sent from my iPad (sorry for spelling mistakes)

On 2012-08-07, at 20:30, lars hofhansl <[EMAIL PROTECTED]> wrote:

> I filed HBASE-6522. It is a trivial change to make locks and leases available to coprocessors.
> So checkAndSet type operations can then be implemented via coprocessor endpoints: lock row, check, fail or update, unlock row.
> Since the patch is so simple I'll commit that soon (to 0.94.2 and 0.96)
> -- Lars
> ________________________________
> From: lars hofhansl <[EMAIL PROTECTED]>
> Sent: Tuesday, August 7, 2012 8:55 AM
> Subject: Re: CheckAndAppend Feature
> There is no such functionality currently, and there is no good way to simulate that.
> Currently that cannot even be done with a coprocessor endpoint, because region coprocessors have no way to create a region lock (just checked the code).
> (That is something we have to change I think - I will create an issue once the Jira system is back from the walk in the park).
> -- Lars
> ----- Original Message -----
> From: Jerry Lam <[EMAIL PROTECTED]>
> To: user <[EMAIL PROTECTED]>
> Cc:
> Sent: Tuesday, August 7, 2012 8:22 AM
> Subject: CheckAndAppend Feature
> Hi HBase community:
> I checked the HTable API, it has checkAndPut and checkAndDelete but I'm
> looking for checkAndAppend. Is there a way to simulate similarly?
> For instance, I want to check the last 32 bytes of a value (let assume that
> it has 128 bytes in total) in a column before appending atomically some
> values into it.
> Thanks!
> Jerry