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From Lsshiu <lss...@gmail.com>
Subject Re: New htable slow
Date Mon, 28 Jan 2013 12:48:46 GMT
Hi Traiq,
    I'll try that and update the result , thanks.

> It does. These excerpts from Hbase Definitive Guide might help you in a
> better fashion :
> 
> "HTablePool:
> Instead of creating an HTable instance for every request from your client
> application, it
> makes much more sense to create one initially and subsequently reuse them.
> The primary reason for doing so is that creating an HTable instance is a
> fairly expensive
> operation that takes a few seconds to complete. In a highly contended
> environment
> with thousands of requests per second, you would not be able to use this
> approach at
> all—creating the HTable instance would be too slow. You need to create the
> instance
> at startup and use it for the duration of your client’s life cycle.
> There is an additional issue with the HTable being reused by multiple
> threads within
> the same process.
> 
> The HTable class is not thread-safe, that is, the local write buffer is not
> guarded against concurrent modifications. Even if you were to use
> setAutoFlush(true) this is not advisable. Instead, you should use
> one instance of HTable for each thread you are running in your client
> application.
> 
> Clients can solve this problem using the HTablePool class. It only serves
> one purpose,
> namely to pool client API instances to the HBase cluster."
> 
> HTH
> 
> Warm Regards,
> Tariq
> https://mtariq.jux.com/
> cloudfront.blogspot.com
> 
> 
> On Mon, Jan 28, 2013 at 5:54 PM, Lsshiu <lsshiu@gmail.com> wrote:
> 
>> Hi Tariq,
>>    Thanks for the update, I'll try it. Btw , will put operation makes any
>> performance difference using htable or htablepool ?
>> 
>> 
>>> Use "HTbalePool" instead and see if it gives you better performance.
>>> Creating an HTable instance is a fairly expensive operation that takes a
>>> few seconds to complete.
>>> 
>>> Warm Regards,
>>> Tariq
>>> https://mtariq.jux.com/
>>> cloudfront.blogspot.com
>>> 
>>> 
>>> On Mon, Jan 28, 2013 at 5:35 PM, Lsshiu <lsshiu@gmail.com> wrote:
>>> 
>>>> 
>>>> 
>>>> Hi Tariq,
>>>>   Thanks for the tip, but I only opened a few htable instances. The
>>>> total region numbers were quite many (more than 70000 ) though.
>>>> 
>>>>> Hi there,
>>>>> 
>>>>>   Do you have too many Htable instances opened simultaneously?It's not
>>>>> advisable to do so.
>>>>> 
>>>>> Warm Regards,
>>>>> Tariq
>>>>> https://mtariq.jux.com/
>>>>> cloudfront.blogspot.com
>>>>> 
>>>>> 
>>>>> On Mon, Jan 28, 2013 at 5:00 PM, Lsshiu <lsshiu@gmail.com> wrote:
>>>>> 
>>>>>> Hi
>>>>>> In my 0.90.6 hbase environment , each time when I try "new htable,
"
>> it
>>>>>> was slow. "Put " also slow too. Can I turn on some kind of trace
to
>> know
>>>>>> the exact time spent in each detail function call? Thanks.
>> 

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