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From Guilherme Germoglio <germog...@gmail.com>
Subject Re: Problems when executing many (?) HTable.lockRow()
Date Sun, 10 May 2009 00:02:42 GMT
On Sat, May 9, 2009 at 8:36 PM, Ryan Rawson <ryanobjc@gmail.com> wrote:

> if we had a compare and set operation would this help you?
>

Compare and set wouldn't be the same as HTable.checkAndSave()
http://hadoop.apache.org/hbase/docs/current/api/org/apache/hadoop/hbase/client/HTable.html#checkAndSave(org.apache.hadoop.hbase.io.BatchUpdate,%20org.apache.hadoop.hbase.io.HbaseMapWritable,%20org.apache.hadoop.hbase.client.RowLock)
?

Also, since the values I'm getting with multiple threads (when changing
hbase.regionserver.handler.count) are not sufficient, I'll change my schema
and use checkAndSave (I hope :-).


> Another thing, normally hbase regionserver only runs 10 ipc handler
> threads... I'm not sure how relevant or important this is yet. Holding a
> row
> open should not tie up an ipc thread though.
>
> On May 9, 2009 4:19 PM, "Guilherme Germoglio" <germoglio@gmail.com> wrote:
>
> Hey Ryan,
>
> Thank for such a quick response!
>
> The log is here: http://germoglio.googlepages.com/log.zip Unfortunately, I
> wasn't running with debug on. I'll do it tomorrow in order to get more data
> (Will I be able to find how to turn on debug in the mailing list archives
> or
> in hbase wiki?). Also, you will notice that the log is only from the master
> server. The reason for this is that I'm running on the pseudodistributed
> mode and the region server log has only one message "2009-05-09
> 19:04:26,242
> WARN org.apache.hadoop.hbase.regionserver.HRegionServer: Not starting a
> distinct region server because hbase.master is set to 'local' mode".
>
> Thank you for the advice. I understand that a simple put doesn't make sense
> to lock a row. However, I'm just considering the performance of it. If the
> put operation into a single row (which I think is the fastest operation)
> isn't fast enough for my project, I'll not even try what I'm really
> intending to do, which is atomically getting a value, modifying it (not
> necessarily incrementing it), and then putting it back to the table.
>
> I wasn't expecting great performance either, but is it ok to execute a
> single put into a locked row in 5~10 minutes?
>
> On Sat, May 9, 2009 at 7:54 PM, Ryan Rawson <ryanobjc@gmail.com> wrote: >
> Hey Guilherme, > > We'd ...
> --
>
> Guilherme msn: guigermoglio@hotmail.com homepage:
> http://germoglio.googlepages.com
>



-- 
Guilherme

msn: guigermoglio@hotmail.com
homepage: http://germoglio.googlepages.com

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