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5. Join Patterns > Reduce Side Join
Reduce Side Join
The reduce side join pattern can take the longest time to execute compared to the other join patterns, but it is simple to implement and supports all the different join operations discussed in the previous section.
A reduce side join is arguably one of the easiest implementations of a join in MapReduce, and therefore is a very attractive choice. It can be used to execute any of the types of joins described above with relative ease and there is no limitation on the size of your data sets. Also, it can join as many data sets together at once as you need. All that said, a reduce side join will likely require a large amount of network bandwidth because the bulk of the data is sent to the reduce phase. This can take some time, but if you have resources available and aren’t concerned about execution time, by all means use it! Unfortunately, if all of the data sets are large, this type of....
