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Posted to common-user@hadoop.apache.org by Stas Oskin <st...@gmail.com> on 2009/05/26 14:31:38 UTC
InputStream.open() efficiency
Hi.
I'm looking to find out, how the InputStream.open() + skip(), compares to
keeping a handle of InputStream() and just seeking the position.
Has anyone compared these approaches, and can advice on their speed?
Regards.
Re: InputStream.open() efficiency
Posted by Stas Oskin <st...@gmail.com>.
Hi.
Thanks for the advice.
Regards.
2009/5/26 Raghu Angadi <ra...@yahoo-inc.com>
> Stas Oskin wrote:
>
>> Hi.
>>
>> Thanks for the answer.
>>
>> Would up to 5 minute of handlers cause any issues?
>>
>
> 5 min should not cause any issues..
>
> And same about writing?
>>
>
> writing is not affected by the couple of issues I mentioned. Writing over a
> long time should work as well as writing over shorter time.
>
> Raghu.
>
>
> Regards.
>>
>> 2009/5/26 Raghu Angadi <ra...@yahoo-inc.com>
>>
>> 'in.seek(); in.read()' is certainly better than,
>>> 'in = fs.open(); in.seek(); in.read()'
>>>
>>> The difference is is exactly one open() call. So you would save an RPC to
>>> NameNode.
>>>
>>> There are couple of issues that affect apps that keep the handlers open
>>> very long time (many hours to days).. but those will be fixed soon.
>>>
>>> Raghu.
>>>
>>>
>>> Stas Oskin wrote:
>>>
>>> Hi.
>>>>
>>>> I'm looking to find out, how the InputStream.open() + skip(), compares
>>>> to
>>>> keeping a handle of InputStream() and just seeking the position.
>>>>
>>>> Has anyone compared these approaches, and can advice on their speed?
>>>>
>>>> Regards.
>>>>
>>>>
>>>>
>>
>
Re: InputStream.open() efficiency
Posted by Raghu Angadi <ra...@yahoo-inc.com>.
Stas Oskin wrote:
> Hi.
>
> Thanks for the answer.
>
> Would up to 5 minute of handlers cause any issues?
5 min should not cause any issues..
> And same about writing?
writing is not affected by the couple of issues I mentioned. Writing
over a long time should work as well as writing over shorter time.
Raghu.
> Regards.
>
> 2009/5/26 Raghu Angadi <ra...@yahoo-inc.com>
>
>> 'in.seek(); in.read()' is certainly better than,
>> 'in = fs.open(); in.seek(); in.read()'
>>
>> The difference is is exactly one open() call. So you would save an RPC to
>> NameNode.
>>
>> There are couple of issues that affect apps that keep the handlers open
>> very long time (many hours to days).. but those will be fixed soon.
>>
>> Raghu.
>>
>>
>> Stas Oskin wrote:
>>
>>> Hi.
>>>
>>> I'm looking to find out, how the InputStream.open() + skip(), compares to
>>> keeping a handle of InputStream() and just seeking the position.
>>>
>>> Has anyone compared these approaches, and can advice on their speed?
>>>
>>> Regards.
>>>
>>>
>
Re: InputStream.open() efficiency
Posted by Stas Oskin <st...@gmail.com>.
Hi.
Thanks for the answer.
Would up to 5 minute of handlers cause any issues?
And same about writing?
Regards.
2009/5/26 Raghu Angadi <ra...@yahoo-inc.com>
>
> 'in.seek(); in.read()' is certainly better than,
> 'in = fs.open(); in.seek(); in.read()'
>
> The difference is is exactly one open() call. So you would save an RPC to
> NameNode.
>
> There are couple of issues that affect apps that keep the handlers open
> very long time (many hours to days).. but those will be fixed soon.
>
> Raghu.
>
>
> Stas Oskin wrote:
>
>> Hi.
>>
>> I'm looking to find out, how the InputStream.open() + skip(), compares to
>> keeping a handle of InputStream() and just seeking the position.
>>
>> Has anyone compared these approaches, and can advice on their speed?
>>
>> Regards.
>>
>>
>
Re: InputStream.open() efficiency
Posted by Raghu Angadi <ra...@yahoo-inc.com>.
'in.seek(); in.read()' is certainly better than,
'in = fs.open(); in.seek(); in.read()'
The difference is is exactly one open() call. So you would save an RPC
to NameNode.
There are couple of issues that affect apps that keep the handlers open
very long time (many hours to days).. but those will be fixed soon.
Raghu.
Stas Oskin wrote:
> Hi.
>
> I'm looking to find out, how the InputStream.open() + skip(), compares to
> keeping a handle of InputStream() and just seeking the position.
>
> Has anyone compared these approaches, and can advice on their speed?
>
> Regards.
>