Hi! Tom White's "Hadoop: The Definitive Guide" is probably the best source for information on this (apart from the code itself ;-) Look at MergeManagerImpl.java btw in case you are so inclined).
HTH Ravi On Friday, October 25, 2013 2:36 PM, - <[email protected]> wrote: Hi All, Can anyone provide documentation regarding how on-disk merge on reduce phase works in detail in Hadoop 2.2.0? There is an explanation in this page but I am afraid it could be outdated since what I observe in my log files is a bunch of "OnDiskMerger - Thread to merge on-disk map-outputs" work at the end of merge phase. Thanks, -
