193Algebraic Optimization of RDF Graph Pattern Queries on MapReduce
6.3.4 ComPlementary oPtimization teChniQues on maPreDuCe
There have been other compile-time and run-time techniques to optimize join pro-
cessing on MapReduce. Though some of this work is pursued outside the context of
RDF and SPARQL, they are very relevant to this discussion. Compile-time optimi-
zations include techniques that share scans or results of subexpressions within [28]
or across queries [13,31,35]. A multiway join algorithm [6] has also been proposed
that efciently partitions and replicates tuples across reducers in a way that mini-
mizes the communication cost as well as the required number of MapReduce cycles.
Run-time optimization techniques such as side-way inform ...