Regarding the conclusion, I am parsing the inputs in combiner and reducer differently. For example the output value of mapper is "s:d" where as the output value of combiner is "s,d". So, in reducer, I am assuming the input as "s,d" and trying to parse it. There I got the exception because it got input as "s:d".
I am using hadoop-17. Icouldn't get exactly what you meant by no guarantee on the number of times a combiner is run. Can you please elaborate a bit on this? Thanks Arun C Murthy-2 wrote: > > > On Jul 1, 2008, at 4:04 AM, novice user wrote: > >> >> Hi all, >> I have a query regarding the functionality of combiner. >> Is it possible to ignore combiner code for some of the outputs of >> mapper and >> directly being sent to reducer though combiner is specified in job >> configuration? >> Because, I figured out that, when I am running on large amounts of >> data, >> some of the mapper output is directly reached reducer. I am >> wondering how >> can this be possible when I have specified combiner in the job >> configuration. Can any one please let me know if this thing happens? >> > > Can you elaborate on how you reached the conclusion that the output > of some maps isn't going through the combiner? > > Also, what version of hadoop are you using? hadoop-0.18 onwards there > aren't guarantees on the number of times a combiner is run... > > Arun > >> >> >> -- >> View this message in context: http://www.nabble.com/Combiner-is- >> optional-though-it-is-specified--tp18213887p18213887.html >> Sent from the Hadoop core-user mailing list archive at Nabble.com. >> > > > -- View this message in context: http://www.nabble.com/Combiner-is-optional-though-it-is-specified--tp18213887p18229533.html Sent from the Hadoop core-user mailing list archive at Nabble.com.
