Redis 6.0 Released: Access Control Lists, SSL and Threaded I/O

What happened

Redis 6.0 was released on April 30, 2020, according to the official announcement on the Redis blog, made generally available by Redis creator Salvatore Sanfilippo. The team described it as no shallow update, grouping the new work into security, performance, ease of use and entirely new functionality.

Access control lists and SSL

The biggest, most game-changing feature was access control lists (ACLs), which brought the concept of users to Redis. Each user can have a defined set of capabilities dictating which commands they can run and on which keys, enabling least-privilege access and reducing the risk of mistakes like running FLUSHDB on production. Redis 6 also added the ability to encrypt traffic over SSL, where previously encryption had to be handled by external applications.

Threaded I/O and RESP3

Despite Redis's single-threaded reputation, Redis 6 threaded its I/O: while data access remained single-threaded, reading and writing to sockets was delegated to other threads, freeing the main process to spend more cycles manipulating and retrieving data while retaining transactional characteristics. The release also introduced RESP3, a new version of the Redis protocol that adds richness to results so client libraries can better map responses to host-language types, and added a cluster proxy to help languages without full cluster support.

Client-side caching and new commands

Redis 6 added support for client-side caching, letting sophisticated client libraries store a subset of data in their own process with the speed of local variables while keeping data in sync. The expiration cycle was rewritten for faster, more accurate key expiration, and Sanfilippo surprised the community with a new longest-common-subsequence (LCS) command family for finding non-contiguous sequences among strings.

Why it mattered

Redis 6.0 was a milestone that broadened where Redis could be used. ACLs and SSL made it viable in security-sensitive environments, threaded I/O and client-side caching pushed performance further, and RESP3 laid the groundwork for thinner, more capable client libraries, setting up the programmability and scalability advances of Redis 7.

Related on Skillo

See also: Redis 7.0's Functions and Sharded Pub/Sub.

Sources

• Diving Into Redis 6.0 (official Redis blog)

Published date reflects the original event date (2020-04-30). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.