MapReuse: Reusing Computation in an In-Memory MapReduce System

MapReduce programming model is being increasingly adopted for data intensive high performance computing. Recently, it has been observed that in data-intensive environment, programs are often run multiple times with either identical or slightly-changed input, which creates a significant opportunity for computation reuse. Recognizing the opportunity, researchers have proposed techniques to reuse computation in disk-based MapReduce systems such as Hadoop, but not for in-memory MapReduce (IMMR) systems such as Phoenix. In this paper, we propose a novel technique for computation reuse in IMMR systems, which we refer to as MapReuse. MapReuse detects input similarity by comparing their signatures. It skips re-computing output from a repeated portion of the input, computes output from a new portion of input, and removes output that corresponds to a deleted portion of the input. MapReuse is built on top of an existing IMMR system, leaving it largely unmodified. MapReuse significantly speeds up IMMR, even when the new input differs by 25% compared to the original input.