I don't think that 0.9.3 has been released, so I'm assuming that you're running on branch-0.9.
There's been over 4000 commits between 0.9.3 and 1.3.1, so I'm afraid that this question doesn't have a concise answer: https://github.com/apache/spark/compare/branch-0.9...v1.3.1 To narrow down the potential causes, have you tried comparing 0.9.3 to, say, 1.0.2 or branch-1.0, or some other version that's closer to 0.9? On Fri, May 22, 2015 at 9:43 AM, Shay Seng <s...@urbanengines.com> wrote: > Hi. > I have a job that takes > ~50min with Spark 0.9.3 and > ~1.8hrs on Spark 1.3.1 on the same cluster. > > The only code difference between the two code bases is to fix the Seq -> > Iter changes that happened in the Spark 1.x series. > > Are there any other changes in the defaults from spark 0.9.3 -> 1.3.1 that > would cause such a large degradation in performance? Changes in > partitioning algorithms, scheduling etc? > > shay > >