Thanks very much for your reply Thomas. I search in Mapper.map() method,but i still can't find out the way to retrieve the source file name of the input data,can you describe in more details? for your proposed suggestion,i have some doubts, the names of the three files are random,so we couldn't sort the values by file name,which will not correspond to the order of (value1A,value1B,value1C),e.g "bbbb" "aaaa" "ccccc" key1-value1A key1-value1B key1-value1C
then if we sort the value by file name,the result will be "key1-(value1B,value1A,value1C)" or "key1-(value1C,value1A,value1B)" Maybe i should use some particular rules to sort the values. Thanks Thomas. Up to now i don't know how to retrieve the source file name of the input data within Mapper.map() method,.Anyway,i have some doubts about your proposed suggestion. On Mon, Oct 26, 2009 at 8:59 PM, Thomas Thevis <[email protected]>wrote: > Hi Anty, > > as far as I know, it is possible to retrieve the source file name of the > input data within the Mapper's map() method. > If so, you could use secondary sort on values (have a look at the Hadoop > wiki pages) to propagate the values sorted first by key and second by > filename to the Reducer which could aggregate them in any particukar way. > > Hope that helps > Thomas > > > Anty schrieb: > >> Does MultipleInputs meet this situation? >> Does any one have any idea about this? >> >> On Mon, Oct 26, 2009 at 7:44 PM, Anty <[email protected] <mailto: >> [email protected]>> wrote: >> >> Hi: >> all >> I have a such use case:i have three files,each file is key-value pairs, >> file1: file2: file3: >> key1-value1A key1-value1B key1-value1C >> key2-value2A key2-value2B key2-value2C >> key3-value3A kye3-value3B kye3-value3C >> ..... ...... >> ..... >> now ,i want to write a MR job to generate a file, >> file4: >> key1-(value1A,value1B,value1C) >> key2-(value2A,value2B,value2C) >> key3-(value3A,value3B,value3C) >> .......... >> Any suggestion will be appreciated. >> -- Best Regards >> Anty Rao >> >> >> >> >> -- >> Best Regards >> Anty Rao >> > > -- Best Regards Anty Rao
