Eric Moyer 538f221627 Document that groupByKey will OOM for large keys ... This pull request is my own work and I license it under Spark's open-source license. This contribution is an improvement to the documentation. I documented that the maximum number of values per key for groupByKey is limited by available RAM (see [Datablox][datablox link] and [the spark mailing list][list link]). Just saying that better performance is available is not sufficient. Sometimes you need to do a group-by - your operation needs all the items available in order to complete. This warning explains the problem. [datablox link]: http://databricks.gitbooks.io/databricks-spark-knowledge-base/content/best_practices/prefer_reducebykey_over_groupbykey.html [list link]: http://apache-spark-user-list.1001560.n3.nabble.com/Understanding-RDD-GroupBy-OutOfMemory-Exceptions-tp11427p11466.html Author: Eric Moyer <eric_moyer@yahoo.com> Closes #3936 from RadixSeven/better-group-by-docs and squashes the following commits: 5b6f4e9 [Eric Moyer] groupByKey docs naming updates 238e81b [Eric Moyer] Doc that groupByKey will OOM for large keys		2015-01-08 11:55:23 -08:00
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src	Document that groupByKey will OOM for large keys	2015-01-08 11:55:23 -08:00
pom.xml	SPARK-4159 [CORE] Maven build doesn't run JUnit test suites	2015-01-06 12:02:08 -08:00