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From Michael Segel <michael_se...@hotmail.com>
Subject Re: CheckAndAppend Feature
Date Wed, 08 Aug 2012 00:54:52 GMT
While this may be a trivial fix, have you considered possible down sides to the implementation?

I'm not sure its a bad idea, but one that could have some potential issues when put into practice.


-Mike

On Aug 7, 2012, at 7:30 PM, lars hofhansl <lhofhansl@yahoo.com> 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 <lhofhansl@yahoo.com>
> To: "user@hbase.apache.org" <user@hbase.apache.org> 
> 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 <chilinglam@gmail.com>
> To: user <user@hbase.apache.org>
> 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
> 


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