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From Bob Schulze <b.schu...@ecircle.com>
Subject Re: Pooling HTable?
Date Fri, 24 Apr 2009 08:43:23 GMT
Thx a lot. I may help too.

Bob

Jonathan Gray schrieb:
> File issued.
> 
> https://issues.apache.org/jira/browse/HBASE-1341
> 
> If no one else picks it up, I will assign the issue to myself next week
> and take care of it.
> 
> JG
> 
> On Thu, April 23, 2009 9:47 am, Tom Nichols wrote:
>> If what you say is true in the general case, it is probably advisable
>> to add this as a feature.  If one other person needed it, it would seem
>> fine to just DIY.  But it sounds like in general something users would
>> want.  If you could file an issue or even contribute some code that would
>> be great.
>>
>> -Tom
>>
>>
>>
>> On Thu, Apr 23, 2009 at 12:29 PM, Jonathan Gray <jlist@streamy.com>
>> wrote:
>>
>>> Bob,
>>>
>>>
>>> In my experience, it does make sense to pool HTable instances.
>>>
>>>
>>> Internally we use something we call HBaseRef that does this for us.
>>>  The
>>> general API of it is just HBaseRef.getTable(String) and
>>> HBaseRef.putTable(HTable).  This was designed way back in 0.2.1 so
>>> might be a bit overkill today.
>>>
>>> The two things to take in to account w.r.t. HTable:
>>>
>>>
>>> - Instantiating a new HTable is costly, often times an order of
>>> magnitude or more slower than a single random read.  This is really what
>>> we want to avoid in a web-facing app w/ low latency requirements.
>>>
>>> - All testing and benchmarking has shown that there is no performance
>>> difference for READS in different threads sharing a single HTable.
>>>  WRITES
>>> do benefit from using a unique HTable per thread.
>>>
>>> So in practice, you do want to pool/reuse HTable instances because you
>>> want to keep latency low.  Might be useful to actually make an
>>> HTablePool
>>> as part of HBase client utilities.
>>>
>>> There's nothing complex about it, but if you are interested in seeing
>>> code let me know and I can file an issue.
>>>
>>> JG
>>>
>>>
>>> On Thu, April 23, 2009 12:25 am, Bob Schulze wrote:
>>>
>>>> Is Hbase' Connection manager already taking care of the connection
>>>> pooling? Does it make sense to Pool HTable instances in a
>>>> multi-threaded (web like) usage scenario?
>>>>
>>>>
>>>>
>>>> Thx,
>>>>
>>>>
>>>>
>>>> Bob
>>>>
>>>>
>>>>
>>>>
>>>
>>
> 
> 


-- 

	Bob Schulze
	Head Software Development
	eCircle AG, Munich, Germany
	+49-89-12009-703

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