AWS Blog

Amazon ElastiCache – Now With Redis 2.8.6

Amazon ElastiCache makes it easy for you to create, operate, and scale an in-memory cache. Because ElastiCache contains support for the Memcached and Redis engines, it is compatible with a wide variety of existing applications.

I’m happy to announce that ElastiCache now supports version 2.8.6 of Redis and that you can start using it today:

New Features
The new release of Redis includes support for lots of cool new features. Here are some of the most important ones:

Partial Resynchronization With Slaves – If the connection between a master node and a slave node is momentarily broken, the master now accumulates data that is destined for the slave in a backlog buffer. If the connection is restored before the buffer becomes full, a quick partial resync will be done instead of a potentially longer full resync. You can use the new repl-backlog-size parameter to set the size of the buffer and the repl-backlog-ttl parameter to control its time to live, measured in seconds since the last successful communication  between the master and the slave.

Better Consistency SupportYou can now configure Redis to stop accepting write operations if less than a certain number of slaves are connected (the min-slaves-to-write parameter) or if the time lag between master and slave has become unacceptably high (the min-slaves-max-lag parameter).

New SCAN Commands – You can use the new SCAN, HSCAN, ZSCAN, and SSCAN commands to incrementally iterate over a Redis collection. You can opt to scan all elements or only those which match a regular expression pattern.

Keyspace Event Notification – Redis client apps can now subscribe to PubSub channels in order to receive notification of changes that affect a data set. The subscription model is very flexible and can be configured to generate one or more events in response to a wide range of operations on the data set. You can read about Redis Keyspace Notifications to learn more.

As I mentioned earlier, this new version of the Redis engine is available now and you can start using it today. You can launch a new ElastiCache for Redis cluster or you can upgrade an existing cluster to version 2.8.6.

— Jeff;