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From Michael Segel <michael_se...@hotmail.com>
Subject Re: Why only check1-and-putMany and check1-and-deleteMany?
Date Sun, 18 Nov 2012 20:15:02 GMT
Ok, maybe this is a silly question on my part.... 

Could you define what you mean by check and append? 
With respect to HBase, how would that be different from check and put? 


On Nov 18, 2012, at 12:28 AM, Mike Spreitzer <mspreitz@us.ibm.com> wrote:

> I am not looking at the trunk.  I am just a user looking at the interface 
> documented on the web site and wondering why the atomic composite 
> functionality is so limited.  It is not hard to imagine an expanded 
> interface that allows checking an arbitrary set of columns and, if each 
> has a value specified for it, doing an arbitrary set of Mutations.
> 
> Thanks,
> Mike
> 
> 
> 
> From:   Ted Yu <yuzhihong@gmail.com>
> To:     user@hbase.apache.org
> Date:   11/17/2012 11:44 PM
> Subject:        Re: Why only check1-and-putMany and check1-and-deleteMany?
> 
> 
> 
> Are you looking at trunk code ?
> 
> In trunk, take a look at HRegion.checkAndMutate() where you can specify
> ByteArrayComparable which does the comparison (matching).
> There is still the limit of single value:
>        } else if (result.size() == 1 && !valueIsNull) {
>          KeyValue kv = result.get(0);
> 
> For the moment, only Put and Delete are supported:
> 
>    if (!isPut && !(w instanceof Delete))
>      throw new DoNotRetryIOException("Action must be Put or Delete");
> If you have suggestion on how the check part can be more general, please
> comment.
> 
> Thanks
> 
> On Sat, Nov 17, 2012 at 7:30 PM, Mike Spreitzer <mspreitz@us.ibm.com> 
> wrote:
> 
>> If I understand correctly, an HTable has two composite atomic 
> operations,
>> checkAndPut and checkAndDelete.  The check part checks just a single
>> column's value.  Why not allow checking more than one column?
>> 
>> Why no checkAndAppend?
>> 
>> The checkAndPut operation can put to multiple columns, right?  And the
>> checkAndDelete operation can delete multiple columns, right?  Why not 
> let
>> them be mixed?  Why not checkAndMutate?
>> 
>> Thanks!
>> Mike
> 


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