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From Michael Dagaev <michael.dag...@gmail.com>
Subject Re: Question on RowLock
Date Mon, 16 Feb 2009 17:28:02 GMT
Thanks, Jonathan !

On Mon, Feb 16, 2009 at 7:24 PM, Jonathan Gray <jlist@streamy.com> wrote:
> Michael,
>
> Stack is exactly right.  RowLocks are definitely intended to be used in this
> way (this is how we use them, primarily as a method for an atomic read/write
> operation).
>
> You need to explicitly unlock them, but also be aware that they have a lease
> just as a scanner does, so they will always eventually unlock themselves (in
> the case that your client dies, etc).
>
> JG
>
>> -----Original Message-----
>> From: saint.ack@gmail.com [mailto:saint.ack@gmail.com] On Behalf Of
>> stack
>> Sent: Monday, February 16, 2009 8:28 AM
>> To: hbase-user@hadoop.apache.org
>> Subject: Re: Question on RowLock
>>
>> See how you can lock a row -- it returns a RowLock instance -- here
>> http://hadoop.apache.org/hbase/docs/r0.19.0/api/org/apache/hadoop/hbase
>> /client/HTable.html#lockRow(byte[]).
>> Then see how elsewhere in HTable, all operations optionally take a
>> RowLock
>> instance.  Unlock the row when done using this method:
>> http://hadoop.apache.org/hbase/docs/r0.19.0/api/org/apache/hadoop/hbase
>> /client/HTable.html#unlockRow(org.apache.hadoop.hbase.client.RowLock)
>> .
>>
>> A single server at any one time will be hosting the region that
>> contains the
>> row you are locking.  When you get a RowLock its held by this host.
>> Ergo,
>> no need for it to be distributed.
>>
>> St.Ack
>>
>>
>> On Mon, Feb 16, 2009 at 8:07 AM, Michael Dagaev
>> <michael.dagaev@gmail.com>wrote:
>>
>> > Hi, all
>> >
>> >    Is this class intended for public use?
>> >
>> >   Can I use it to lock a row, read and update the row data
>> > and unlock the row ? I guess  it is not a distributed lock I need
>> > but I want to be sure ...
>> >
>> > What I need is a some way to lock a row, read and update the data
>> > and unlock the row after the update.
>> >
>> > Thank you for your cooperation,
>> > M.
>> >
>
>

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