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From Lucian Iordache <lucian.george.iorda...@gmail.com>
Subject Re: Lease does not exist exceptions
Date Mon, 24 Oct 2011 15:04:30 GMT
Hi all,

I have exactly the same problem that Eran had.
But there is something I don't understand: in my case, I have set the lease
time to 240000 (4 minutes). But most of the map tasks that are failing run
about 2 minutes. How is it possible to get a LeaseException if the task runs
less than the configured time for a lease?

Regards,
Lucian Iordache

On Fri, Oct 21, 2011 at 12:34 AM, Eran Kutner <eran@gigya.com> wrote:

> Perfect! Thanks.
>
> -eran
>
>
>
> On Thu, Oct 20, 2011 at 23:27, Jean-Daniel Cryans <jdcryans@apache.org
> >wrote:
>
> > hbase.regionserver.lease.period
> >
> > Set it bigger than 60000.
> >
> > J-D
> >
> > On Thu, Oct 20, 2011 at 2:23 PM, Eran Kutner <eran@gigya.com> wrote:
> > >
> > > Thanks J-D!
> > > Since my main table is expected to continue growing I guess at some
> point
> > > even setting the cache size to 1 will not be enough. Is there a way to
> > > configure the lease timeout?
> > >
> > > -eran
> > >
> > >
> > >
> > > On Thu, Oct 20, 2011 at 23:16, Jean-Daniel Cryans <jdcryans@apache.org
> > >wrote:
> > >
> > > > On Wed, Oct 19, 2011 at 12:51 PM, Eran Kutner <eran@gigya.com>
> wrote:
> > > >
> > > > > Hi J-D,
> > > > > Thanks for the detailed explanation.
> > > > > So if I understand correctly the lease we're talking about is a
> > scanner
> > > > > lease and the timeout is between two scanner calls, correct? I
> think
> > that
> > > > > make sense because I now realize that jobs that fail (some jobs
> > continued
> > > > > to
> > > > > fail even after reducing the number of map tasks as Stack
> suggested)
> > use
> > > > > filters to fetch relatively few rows out of a very large table, so
> > they
> > > > > could be spending a lot of time on the region server scanning rows
> > until
> > > > it
> > > > > reached my setCaching value which was 1000. Setting the caching
> value
> > to
> > > > 1
> > > > > seem to allow these job to complete.
> > > > > I think it has to be the above, since my rows are small, with just
> a
> > few
> > > > > columns and processing them is very quick.
> > > > >
> > > >
> > > > Excellent!
> > > >
> > > >
> > > > >
> > > > > However, there are still a couple ofw thing I don't understand:
> > > > > 1. What is the difference between setCaching and setBatch?
> > > > >
> > > >
> > > > * Set the maximum number of values to return for each call to next()
> > > >
> > > > VS
> > > >
> > > > * Set the number of rows for caching that will be passed to scanners.
> > > >
> > > > The former is useful if you have rows with millions of columns and
> you
> > > > could
> > > > setBatch to get only 1000 of them at a time. You could call that
> > intra-row
> > > > scanning.
> > > >
> > > >
> > > > > 2. Examining the region server logs more closely than I did
> yesterday
> > I
> > > > see
> > > > > a log of ClosedChannelExceptions in addition to the expired leases
> > (but
> > > > no
> > > > > UnknownScannerException), is that expected? You can see an excerpt
> of
> > the
> > > > > log from one of the region servers here:
> > http://pastebin.com/NLcZTzsY
> > > >
> > > >
> > > > It means that when the server got to process that client request and
> > > > started
> > > > reading from the socket, the client was already gone. Killing a
> client
> > does
> > > > that (or killing a MR that scans), so does SocketTimeoutException.
> This
> > > > should probably go in the book. We should also print something nicer
> :)
> > > >
> > > > J-D
> > > >
> >
>

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