Dan,
One of the ways we get around the scanner timeouts is to keep track of
the last row that was read and restart the scan from that row.
--------------
boolean scanComplete = false;
while (!scanComplete){
long lastFetchTs = 0;
scanner = table.getScanner(scan);
Result row = null;
while ((row = scanner.next()) != null) {
lastFetchTs = System.currentTimeMillis();
....
....
....
if(hasLeaseExpired(lastFetchTs)){
scanner.close();
scan.setStartRow(row.getRow());
break;
}
}
if(row == null){
scanComplete = true;
}
}
------------------
Alok
On Wed, Mar 20, 2013 at 9:32 AM, Dan Crosta <[email protected]> wrote:
> I'm confused -- I only see one setting in CDH manager, what is the name of
> the other setting?
>
> Our load is moderately frequent small writes (in batches of 1000 cells at a
> time, typically split over a few hundred rows -- these complete very fast, we
> haven't seen any timeouts there), and infrequent batches of large reads
> (scans), which is where we do see timeouts. My guess is that the timeout is
> more due to our application taking some time -- apparently more than 60s --
> to process the results of each scan's output, rather than due to slowness in
> HBase itself, which tends to be only moderately loaded (judging by CPU,
> network, and disk) while we do the reads.
>
> Thanks,
> - Dan
>
> On Mar 17, 2013, at 2:20 PM, Ted Yu wrote:
>
>> The lease timeout is used by row locking too.
>> That's the reason behind splitting the setting into two config parameters.
>>
>> How is your load composition ? Do you mostly serve reads from HBase ?
>>
>> Cheers
>>
>> On Sun, Mar 17, 2013 at 1:56 PM, Dan Crosta <[email protected]> wrote:
>>
>>> Ah, thanks Ted -- I was wondering what that setting was for.
>>>
>>> We are using CDH 4.2.0, which is HBase 0.94.2 (give or take a few
>>> backports from 0.94.3).
>>>
>>> Is there any harm in setting the lease timeout to something larger, like 5
>>> or 10 minutes?
>>>
>>> Thanks,
>>> - Dan
>>>
>>> On Mar 17, 2013, at 1:46 PM, Ted Yu wrote:
>>>
>>>> Which HBase version are you using ?
>>>>
>>>> In 0.94 and prior, the config param is hbase.regionserver.lease.period
>>>>
>>>> In 0.95, it is different. See release notes of HBASE-6170
>>>>
>>>> On Sun, Mar 17, 2013 at 11:46 AM, Dan Crosta <[email protected]> wrote:
>>>>
>>>>> We occasionally get scanner timeout errors such as "66698ms passed since
>>>>> the last invocation, timeout is currently set to 60000" when iterating a
>>>>> scanner through the Thrift API. Is there any reason not to raise the
>>>>> timeout to something larger than the default 60s? Put another way, what
>>>>> resources (and how much of them) does a scanner take up on a thrift
>>> server
>>>>> or region server?
>>>>>
>>>>> Also, to confirm -- I believe "hbase.rpc.timeout" is the setting in
>>>>> question here, but someone please correct me if I'm wrong.
>>>>>
>>>>> Thanks,
>>>>> - Dan
>>>>>
>>>>>
>>>>>
>>>
>>>
>
