Memcached Cache Expiration Mechanism

memcached is a high-performance system for storing and retrieving data in memory, which improves system performance by reducing disk I/O operations through a cache expiration mechanism.

Setting Expiration Time

In memcached, expiration time can be set in the following ways:

1. Using Command Line Options

memcached -m 64 -p 11211 -d 10000 -c cache_size=16 -v expire=3600

In this example, -d 10000 indicates an expiration time of 10 seconds (10000ms), and -c cache_size=16 indicates a cache size of 16 bytes.

2. Using Configuration Files

Expiration time can be set in memcached's configuration file (typically /etc(memcached)/memcached.conf):

 expire 3600

Handling Expired Data

When memcached's cache exceeds the specified expiration time, memcached will automatically delete it. However, in some cases, we may need to manually handle expired data.

1. Using the flush Command

You can use the following command to delete all cached data:

memcached -m 64 -p 11211 -d 10000 -c cache_size=16 -v flush all

Alternatively, use the flush command:

memcached -m 64 -p 11211 -d 10000 -c cache_size=16 -v expire=3600 flush key1 value1

2. Using Hooks

Hooks (hook) can be used to handle expired data. Hooks are a feature of memcached that allows us to write custom scripts to handle cache deletion and updates.

For more information about hooks, see memcached documentation.

3. Using Other Solutions

There are also third-party solutions, such as Redis and Hazelcast, which provide more complex expiration mechanisms that can be customized according to specific requirements.