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

Switch to Threaded View
HBase, mail # user - Inconsistent scan performance with caching set to 1


Copy link to this message
-
Re: Inconsistent scan performance with caching set to 1
Jay T 2012-08-30, 16:24
 Thanks Stack for pointing us in the right direction. Indeed it was the
tcpNodeDelay setting. We set these to be true.

ipc.server.tcpnodelay ==> true
hbase.ipc.client.tcpnodelay ==> true

All reads that previously had the 40ms overhead are now between 2 and 3
ms like we would expect them to be.

Are these settings worthy of being put in the Hbase online book  ?

Thanks,
Jay

On 8/30/12 2:07 AM, Stack wrote:
> On Wed, Aug 29, 2012 at 10:42 AM, Wayne<[EMAIL PROTECTED]>  wrote:
>> This is basically a read bug/performance problem. The execution path
>> followed when the caching is used up is not consistent with the initial
>> execution path/performance. Can anyone help shed light on this? Was there
>> any changes to 0.94 to introduce this (we have not tested on other
>> versions)? Any help or advice would be appreciated. As it is stands we are
>> looking to have to reverse engineer every aspect of a read from both the
>> hbase client and server components to find and fix.
>>
>> One additional lead is that not all rows behave like this. Only certain
>> small rows seem to do this consistently. Most of our rows are larger and do
>> not have this behavior.
>>
> Nagles?  (https://issues.apache.org/jira/browse/HBASE-2125)
> St.Ack