Apache Hadoop 2.6.5 Release Notes

These release notes cover new developer and user-facing incompatibilities, important issues, features, and major improvements.

Made CanBuffer interface public for use in client applications.

Two recommendations for the mapreduce.jobhistory.loadedtasks.cache.size property: 1) For every 100k of cache size, set the heap size of the Job History Server to 1.2GB. For example, mapreduce.jobhistory.loadedtasks.cache.size=500000, heap size=6GB. 2) Make sure that the cache size is larger than the number of tasks required for the largest job run on the cluster. It might be a good idea to set the value slightly higher (say, 20%) in order to allow for job size growth.

Fix inconsistent value type ( String and Array ) of the “type” field for LeafQueueInfo in response of RM REST API