Glossary
This page defines key terms used in ApsaraDB for Memcache documentation.
Memcached
Memcached is a high-performance distributed caching system for in-memory objects. ApsaraDB for Memcache is compatible with both the Memcached binary protocol and text protocol. For the official Memcached project, see Memcached.
Instance ID
An instance is the basic unit for using ApsaraDB for Memcache, and each instance corresponds to an isolated user space. Each instance has a unique instance ID. Different capacity specifications have different queries per second (QPS) limits and traffic limits. View the instance ID list on the ApsaraDB for Memcache console.
Connection address
The host address used to connect to an ApsaraDB for Memcache instance. The address is in domain name format. To find the connection address, go to Instance Information > Basic Information > Instance Details > Intranet Address.
Connection password
The password used to authenticate connections to ApsaraDB for Memcache. Set the password when you purchase an instance, or reset it at any time after purchase.
Hit rate
The ratio of successful cache reads to total read requests.
Formula: Hit rate = successful reads / total reads
For example, a hit rate of 80% means 8 out of every 10 read requests are served from the cache. A higher hit rate reduces backend load and improves response times.
Password-free access
An access mode that allows connections to an ApsaraDB for Memcache instance from an authorized ECS instance without a password. For setup instructions, see Password-free access.
SASL
Simple Authentication and Security Layer (SASL) is a framework that adds authentication capabilities to client/server protocols.
Why ApsaraDB for Memcache uses SASL: ApsaraDB for Memcache is a multi-tenant service. SASL authentication isolates and protects each tenant's cached data by using passwords as the underlying security mechanism.
Version support: Memcached has supported SASL since version 1.4.3.
Authentication interval: ApsaraDB for Memcache re-authenticates connections automatically every 60 seconds.
Security guidance: Use a strong password and rotate it regularly.