Garbage Collection In Hadoop

Ranjan Banerjee explains how the Java garbage collector works, using Hadoop as an example:

The reason why we all love Java is due to the fact that we can be careless with memory creations and the work of cleaning the mess is performed by the JVM. On a high level, Java heap memory is classified into two phases:

1) Young (eden) space

2)Old space

The eden space is where newly created objects goto. There are various algorithms for garbage collection, but all of them try to first free memory from the young space and for those long lasting memory objects, they are transferred to the old space.

One common issue that can be noticed in running Map Reduce Applications are GC overhead limit exceeded.

Read on for more, including where you can find GC logs.

Related Posts

Event Sourcing On Kafka

Adam Warski shows how you can use Apache Kafka as your event sourcing data source: There’s a number of great introductory articles, so this is going to be a very brief introduction. With event sourcing, instead of storing the “current” state of the entities that are used in our system, we store a stream of events that relate to these […]

Read More

The Basics Of Kafka Security

Stephane Maarek has a nice post covering some of the basics of securing an Apache Kafka cluster: Once your Kafka clients are authenticated, Kafka needs to be able to decide what they can and cannot do. This is where Authorization comes in, controlled by Access Control Lists (ACL). ACL are what you expect them to be: […]

Read More


March 2017
« Feb Apr »