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From Mike Spreitzer <mspre...@us.ibm.com>
Subject Re: Why only check1-and-putMany and check1-and-deleteMany?
Date Sun, 18 Nov 2012 06:28:10 GMT
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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