How can I get the record number of a SequenceFile?

[Jeremy Chow <co...@gmail.com>]

Hi list,

I've generated a sequence file by a reducer, then I will use it to start the
second map step, which need the record number of that sequence file. How can
it fast ?
thanks a lot.

-- 
My research interests are distributed systems, parallel computing and
bytecode based virtual machine.

http://coderplay.javaeye.com

Re: How can I get the record number of a SequenceFile?

[Deyaa Adranale <de...@iais.fraunhofer.de>]

Hi Jeremy,

I think the key of the map function is the number of the record in a 
sequence file.

I was trying to retrieve the record number in a normal TextInputFormat 
but could not find it. The best what I could use is the byte offset of 
the record, which does not reflex the record number since the records 
might have different lengths. I have even tried to write my own input 
format (for plain text files) but even did not work :-(. anybody could 
give me a hint on this?

regards

Deyaa

Jeremy Chow wrote:
> Hi list,
>
> I've generated a sequence file by a reducer, then I will use it to start the
> second map step, which need the record number of that sequence file. How can
> it fast ?
> thanks a lot.
>
>