Memorystore for Memcached is backed by open source Memcached software. Memorystore currently supports Memcached versions 1.5.16 and 1.6.15. The default version is Memcached 1.5.16.
For instructions on how to upgrade the Memcached version of an instance, see Upgrade the Memcached version of an instance.
For information about how upgrading the Memcached version affects the instance, see About upgrading the Memcached version of an instance.
Version support policy
Memorystore for Memcached supports one patch version for every major OSS Memcached version listed in the Current versions section of this page. The patch is kept up to date on a regular basis during maintenance periods. Memorystore for Memcached monitors for any critical patches that need to be applied to your instance. Critical security patches are rolled out outside of the regular maintenance period. See About maintenance for more details.
Current versions
This table lists the supported Memcached versions and when each version was last updated:
| Memcached version | Last update |
|---|---|
| 1.5.16 | March 26, 2020 |
| 1.6.15 | September 19, 2023 |
Memcached version 1.6.15
The table below outlines Memorystore support of some major features introduced by Memcached version 1.6.15.
| Feature | Description | Supported in Memorystore for Memcached |
|---|---|---|
| Meta protocol | The new meta protocol now has more features than the binary protocol. Anything you can do with the text/binary protocol can be done with the new meta commands. These commands can bring huge benefits to performance and correctness of cache systems. | Yes |
| Batching of response syscalls | The network code has been refactored to allow automatic batching of response syscalls. As a result of this feature, if you submit multiple get commands in the same TCP packet, Memcached tends to send the responses with a single syscall. | Yes |
| Disable watch commands | A configuration to disable watch commands. For more details, see Supported Memcached configurations. | Yes |
| XXH3 hash algorithm | XXH3 hash algorithm has been added to the list of hash table algorithms. For more details, see Supported Memcached configurations. | Yes |
| Watch connevents | Watch connevents command shows real-time entries about connection/disconnection events | Yes |
| Warm Cache Restart | Memcached can now recover its cache in between restarts. | No |
| Extstore | Extstore is an addition to memcached which leaves the hash table and keys in memory, but moves values to external storage (usually flash). | No |
| TLS | Memcached 1.5.13+ supports authentication and encryption via TLS which allows clients to communicate with servers via secure channel. | No |