The equi-join between the log and the reference data can have a large impact on the performance of log processing. Unfortunately, the MapReduce framework is somewhat cumbersome for joins, since it was not originally designed to combine information from two or more data sources. Consequently, adapting well-known join algorithms to MapReduce is not as straightforward as one might hope, and MapReduce programmers often use simple but inefficient algorithms to perform equi-joins.