But if your files DO fit into memory then the datanodes that have copies of the blocks of your file will probably still have them in memory and since maps are typically data local, you will benefit as much as possible.
On 2/10/08 11:17 AM, "Arun C Murthy" <[EMAIL PROTECTED]> wrote: >> Is Hadoop cache frequently/LRU/MRU map input files? Or does it >> upload files >> from the disk each time a file is needed no matter if it was the >> same file >> that was required by the last job on the same node? >> > > There is no concept of caching input files across jobs. > > Hadoop is geared towards dealing with _huge_ amounts of data which > don't fit into memory anyway... and hence doing it across jobs is moot.
