is it possible to view the number of hfiles a GET touches in hbase?

[Richard Tang <tr...@gmail.com>]

Hi,
Given a GET() operation, I want to monitor the number of on-disk hfiles it
touches? GET() may need to
check every in-memory hfiles (block index),  but don't need to touch every
on-disk parts of hfiles. I want to know
how many disk hfile a GET() accesses, that is, how many disk IO a GET() end
up with...

is it possible to obtain this information without hack into hbase source
code?
Richard

Re: is it possible to view the number of hfiles a GET touches in hbase?

[Jean-Daniel Cryans <jd...@apache.org>]

This won't be possible until we add tracing in HBase. It's being
worked on here: https://issues.apache.org/jira/browse/HBASE-6449

J-D

On Fri, Aug 10, 2012 at 4:17 AM, Richard Tang <tr...@gmail.com> wrote:
> Hi,
> Given a GET() operation, I want to monitor the number of on-disk hfiles it
> touches? GET() may need to
> check every in-memory hfiles (block index),  but don't need to touch every
> on-disk parts of hfiles. I want to know
> how many disk hfile a GET() accesses, that is, how many disk IO a GET() end
> up with...
>
> is it possible to obtain this information without hack into hbase source
> code?
> Richard

Re: is it possible to view the number of hfiles a GET touches in hbase?

[jmozah <jm...@gmail.com>]

Hi Richard,

I am not so sure if there is any HBase metrics on this...!!!
But you can use the DataNode metrics like "blocksRead", "readBlockOp" etc to come to some conclusion.


Ganglia may come in handy here..

./Zahoor


On 10-Aug-2012, at 4:47 PM, Richard Tang <tr...@gmail.com> wrote:

> Hi,
> Given a GET() operation, I want to monitor the number of on-disk hfiles it
> touches? GET() may need to
> check every in-memory hfiles (block index),  but don't need to touch every
> on-disk parts of hfiles. I want to know
> how many disk hfile a GET() accesses, that is, how many disk IO a GET() end
> up with...
> 
> is it possible to obtain this information without hack into hbase source
> code?
> Richard