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HBase >> mail # user >> Differences between ScannerTimeoutException and LeaseException during a scanner


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Re: Differences between ScannerTimeoutException and LeaseException during a scanner
Thanks for sharing your experience.

Have you set hbase.rpc.timeout > hbase.regionserver.lease.period in your
environment ?

Cheers

On Thu, Nov 15, 2012 at 7:45 AM, Guillaume Perrot <[EMAIL PROTECTED]>wrote:

> It looks like a "race condition" between the check that the lease is
> expired in HRegionServer.next, and the LeaseListener.leaseExpired methods.
> If the next call from the client is done before the lease listener do its
> job, the scanner still exists in the map but is expired, which causes
> LeaseException instead of UnknownScannerException.
> Indeed I found this in the logs:
>
> 2012-11-15 08:45:34,003 ERROR
> org.apache.hadoop.hbase.regionserver.HRegionServer:
> org.apache.hadoop.hbase.regionserver.LeaseException: lease
> '4939065839430667309' does not exist
>  at
> org.apache.hadoop.hbase.regionserver.Leases.removeLease(Leases.java:231)
> at
>
> org.apache.hadoop.hbase.regionserver.HRegionServer.next(HRegionServer.java:2117)
>  at sun.reflect.GeneratedMethodAccessor31.invoke(Unknown Source)
> at
>
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
>  at java.lang.reflect.Method.invoke(Method.java:597)
> at
>
> org.apache.hadoop.hbase.ipc.WritableRpcEngine$Server.call(WritableRpcEngine.java:364)
>  at
> org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1326)
>
> Then
>
> 2012-11-15 08:48:37,734 INFO
> org.apache.hadoop.hbase.regionserver.HRegionServer: Scanner
> 4939065839430667309 lease expired
>
> The scanner is properly closed way too late!
> I just realized there is already a related issue about this:
> https://issues.apache.org/jira/browse/HBASE-6856
>
> 2012/11/15 Guillaume Perrot <[EMAIL PROTECTED]>
>
> > Hi,
> > Similar questions have been mailed in the past, but they are not clear
> > enough to me, so here is a new one:
> > In HBase 0.90.3, when a client scanner was too slow to advance (no actual
> > next call within 60s), we had a nice ScannerTimeoutException in client
> > (UnknownScannerException in region server).
> > With HBase 0.92.1, when I simulate such a slow scanner I still have this
> > exception.
> >
> > But in our production environment, scanners that used to
> > produce ScannerTimeoutException in HBase 0.90.3 no longer produce them
> > since we upgraded to HBase 0.92.1.
> > Instead we now have:
> > org.apache.hadoop.hbase.regionserver.LeaseException:
> > org.apache.hadoop.hbase.regionserver.LeaseException: lease
> > '2770824890045864909' does not exist
> > at
> org.apache.hadoop.hbase.regionserver.Leases.removeLease(Leases.java:231)
> >  at
> >
> org.apache.hadoop.hbase.regionserver.HRegionServer.next(HRegionServer.java:2117)
> > at sun.reflect.GeneratedMethodAccessor14.invoke(Unknown Source)
> >  at
> >
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> > at java.lang.reflect.Method.invoke(Method.java:597)
> >  at
> >
> org.apache.hadoop.hbase.ipc.WritableRpcEngine$Server.call(WritableRpcEngine.java:364)
> > at
> >
> org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1326)
> >
> > I don't uderstand the workflow leading to this exception instead of a
> > ScannerTimeoutException, any local attempt to reproduce this problem
> leads
> > to a ScannerTimeoutException and not a LeaseException.
> > Any idea ?
> > Thanks in advance.
> >
>
>
>
> --
>   *Guillaume Perrot
> **Software Engineer
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