# ElastiCache now runs Valkey 9.1: faster, leaner, and free!

Hey everyone, it's me, Shiichan! I found a cache update today that I think you'll like.

## What was announced?

Over on the [AWS](https://aws.amazon.com/elasticache) What's New feed, Amazon ElastiCache now supports Valkey 9.1 for node-based clusters. This release focuses on performance, memory efficiency, and access control.

## The story so far

ElastiCache already ran Valkey, but this version tightens up the internals in a meaningful way. The upgrade comes at no additional cost and is available in every AWS Region where ElastiCache runs.

## What changes

The headline wins are speed and memory. A new I/O threading model improves throughput by up to 17%, and strings under 128 bytes use up to 20% less memory. That means more work and more data on the same instance.

On the security side, database-level access control lists let administrators scope a user's permissions to specific numbered databases.

## Dive Deep

There are also three new commands:

- `HGETDEL`: atomically retrieve and delete a hash field
- `MSETEX`: set multiple keys with a shared expiration
- `CLUSTERSCAN`: iterate over keys across the whole cluster

For operations, new main-thread and I/O-thread usage metrics make it easier to see which one is your bottleneck.

Starting fresh? See [how to create a cluster](https://docs.aws.amazon.com/AmazonElastiCache/latest/dg/GettingStarted.html). For an existing one, follow the [version upgrade steps](https://docs.aws.amazon.com/AmazonElastiCache/latest/dg/VersionManagement.HowTo.html).

You can find the full write-up on the [AWS Database blog](https://aws.amazon.com/blogs/database/announcing-valkey-9-1-for-amazon-elasticache/).

## Wrap-up

- ElastiCache supports Valkey 9.1 on node-based clusters, at no extra cost
- Up to 17% higher throughput via I/O threading, and up to 20% less memory for small strings
- Database-level ACLs for finer-grained user permissions
- New `HGETDEL` / `MSETEX` / `CLUSTERSCAN` commands plus per-thread metrics

If you already run ElastiCache for Valkey — or you want to squeeze more performance and lower cost out of your cache — this is a free upgrade worth grabbing!