Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
HBase >> mail # user >> Warning messages in hbase logs


Copy link to this message
-
Re: Warning messages in hbase logs
Vimal,
In my case, for a single client my queries take less than a second (sub-second performance is  on what we were shooting for).
But the same queries when run concurrently gives completely degraded performance. That is the reason I wrote that no-op test case which I have attached in the test HBASE-9410 bug. So many queries trying to execute on a region lead to some sort of lock contentions, is my guess which is causing the slow performance. 
My test case runs fine on 0.95.2 but on 0.94.x even for about 8 concurrent clients it is very high and I see these errors in the log.
You should also try running the test case. You will see bad performance even though the coprocessor function does not do anything.
 
Regards,
- kiru
Kiru Pakkirisamy | webcloudtech.wordpress.com
________________________________
 From: Vimal Jain <[EMAIL PROTECTED]>
To: Kiru Pakkirisamy <[EMAIL PROTECTED]>
Cc: Himanshu Vashishtha <[EMAIL PROTECTED]>; "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>; lars hofhansl <[EMAIL PROTECTED]>
Sent: Wednesday, October 23, 2013 10:50 PM
Subject: Re: Warning messages in hbase logs
 
Hi Kiru,
Can you please elaborate on this ?
On Mon, Oct 21, 2013 at 5:30 PM, Vimal Jain <[EMAIL PROTECTED]> wrote:

Hi Kiru,
>Thanks for the reply.
>My understanding is not very clear  with respect to these warning messages in region server logs.
>When i read documentation , it says its related to slow query logs.
>So is it a issue in earlier versions of hbase and is fixed in 0.96 or is it an issue in my configuration and i have to set some parameters to prevent this?
>Please help in understanding the exact issue.
>
>
>
>
>On Sat, Oct 19, 2013 at 3:31 AM, Kiru Pakkirisamy <[EMAIL PROTECTED]> wrote:
>
>Vimal,
>>Maybe you should try running the test case for HBASE-9410 (with some modifications) and report back.
>>This way Lars/committers/contributors can work on this bug with confirmation.
>>
>>
>>
>>The test case makes a coprocessor call (which does nothing) on a table with regions in all the region servers.
>>Feel free to send me any email in this regards. 
>> 
>>Regards,
>>- kiru
>>
>>
>>
>>Kiru Pakkirisamy | webcloudtech.wordpress.com
>>
>>
>>________________________________
>> From: Vimal Jain <[EMAIL PROTECTED]>
>>To: Himanshu Vashishtha <[EMAIL PROTECTED]>
>>Cc: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>; Kiru Pakkirisamy <[EMAIL PROTECTED]>; lars hofhansl <[EMAIL PROTECTED]>
>>Sent: Thursday, October 17, 2013 9:39 PM
>>
>>Subject: Re: Warning messages in hbase logs
>>
>>
>>
>>Hi.
>>I am still getting these warnings in region server logs.
>>I am still using hbase 0.94.7.
>>Is there any impact of these warning messages ?
>>
>>
>>
>>
>>On Thu, Sep 26, 2013 at 11:19 PM, Himanshu Vashishtha <[EMAIL PROTECTED]> wrote:
>>
>>
>>>
>>>
>>>
>>>
>>>On Thu, Sep 26, 2013 at 4:07 AM, Kiru Pakkirisamy <[EMAIL PROTECTED]> wrote:
>>>
>>>I was on 0.94.11 and still got the same msgs as Vimal. 
>>>>Ultimately, I moved to 0.95.2.
>>>>
>>> 
>>>You know it is a dev release, right? 
>>>
>>>
>>>
>>>
>>>Regards,
>>>>- kiru
>>>>
>>>>
>>>>Kiru Pakkirisamy | webcloudtech.wordpress.com
>>>>
>>>>
>>>>
>>>>________________________________
>>>> From: lars hofhansl <[EMAIL PROTECTED]>
>>>>To: Vimal Jain <[EMAIL PROTECTED]>; "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
>>>>Cc: Kiru Pakkirisamy <[EMAIL PROTECTED]>
>>>>Sent: Wednesday, September 25, 2013 9:46 PM
>>>>
>>>>Subject: Re: Warning messages in hbase logs
>>>>
>>>>
>>>>You probably ran into
>>>>[HBASE-6870] - HTable#coprocessorExec always scan the whole table (0.94.8)
>>>>
>>>>Or maybe one of these:
>>>>
>>>>[HBASE-8806] - Row locks are acquired repeatedly in HRegion.doMiniBatchMutation for duplicate rows. (0.94.10)
>>>>[HBASE-8639] - Poor performance of htable#getscanner in multithreaded environment due to DNS.getDefaultHost() being called in ScannerCallable#prepare() (0.94.9)
>>>>[HBASE-9087] - Handlers being blocked during reads (0.94.11)
>>>>
>>>>
>>>
Thanks and Regards,
Vimal Jain