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From John Beatty <john.bea...@gmail.com>
Subject Re: question about checkAndPut() expected value parameter when testing row nonexistence
Date Mon, 16 Aug 2010 17:34:42 GMT
J-D, thanks. I'll take a crack at submitting a patch containing a fix
plus the unit tests.

john

On Mon, Aug 16, 2010 at 10:28 AM, Jean-Daniel Cryans
<jdcryans@apache.org> wrote:
> John,
>
> Looks like its broken, moreover we don't have any unit tests for
> checkAndPut/Delete. We need to fix that, I opened
> https://issues.apache.org/jira/browse/HBASE-2920
>
> This could be a nice first contribution :)
>
> J-D
>
> On Sat, Aug 14, 2010 at 6:51 PM, John Beatty <john.beatty@gmail.com> wrote:
>> Thanks Ryan, but I seem to be missing something then. It NPEs for me.
>> When running against 0.89.20100726 and providing a null expected value
>> I get the below stack trace (and works like a champ when I provide a
>> byte[0]. I also don't see the transformation you're referring to in
>> HTable.
>>
>> (for reference,
>> http://svn.apache.org/viewvc/hbase/branches/0.89.20100726/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java?view=markup)
>>
>> java.io.IOException: java.io.IOException: java.lang.NullPointerException
>>        at org.apache.hadoop.hbase.regionserver.HRegionServer.convertThrowableToIOE(HRegionServer.java:845)
>>        at org.apache.hadoop.hbase.regionserver.HRegionServer.convertThrowableToIOE(HRegionServer.java:835)
>>        at org.apache.hadoop.hbase.regionserver.HRegionServer.checkAndMutate(HRegionServer.java:1754)
>>        at org.apache.hadoop.hbase.regionserver.HRegionServer.checkAndPut(HRegionServer.java:1773)
>>        at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source)
>>        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
>>        at org.apache.hadoop.hbase.ipc.HBaseRPC$Server.call(HBaseRPC.java:576)
>>        at org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:919)
>> Caused by: java.lang.NullPointerException
>>        at org.apache.hadoop.hbase.regionserver.HRegion.checkAndMutate(HRegion.java:1616)
>>        at org.apache.hadoop.hbase.regionserver.HRegionServer.checkAndMutate(HRegionServer.java:1751)
>>        ... 6 more
>>
>> On Sat, Aug 14, 2010 at 6:34 PM, Ryan Rawson <ryanobjc@gmail.com> wrote:
>>> Nulls end up being transformed into byte[0] in HTable and all is well.
>>>
>>> On Aug 14, 2010 6:33 PM, "John Beatty" <john.beatty@gmail.com> wrote:
>>>> There appears to be a disconnect between the API [1] and the
>>>> implementation [2] of checkAndPut() regarding the expected value
>>>> parameter when the caller wants to make the put conditional on the row
>>>> not existing. The javadoc states that the caller should use a null
>>>> expected value for this purpose, whereas the implementation is
>>>> checking for a 0-length byte[]. If a null expected value is given,
>>>> checkAndPut() will NPE; see HRegion.java:1520 in trunk.
>>>>
>>>> I believe that null, rather than 0-length byte[], should be used for
>>>> requiring row non-existence in checkAndPut(). Besides seeming like the
>>>> right API, a 0-length byte[] is technically a valid row key (and least
>>>> for a little put/get test I did; I found this surprising).
>>>>
>>>> Thoughts?
>>>>
>>>> john
>>>>
>>>> [1]
>>> http://hbase.apache.org/docs/r0.89.20100726/apidocs/org/apache/hadoop/hbase/ipc/HRegionInterface.html#checkAndPut(byte[]
>>> ,
>>>> byte[], byte[], byte[], byte[], org.apache.hadoop.hbase.client.Put)
>>>>
>>>> [2]
>>> http://svn.apache.org/viewvc/hbase/trunk/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java?view=markup
>>>> -- line 1520
>>>
>>
>

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