Memcache is a widely used distributed memory caching system. It is often used to speed up dynamic database-driven websites by caching data and objects in memory to reduce the need for repeated database queries.
**Description**: Stores the specified value in the cache under the given key. The `flags` parameter is used to store metadata about the value, such as its data type or compression method. The `exptime` parameter specifies the expiration time in seconds. The `bytes` parameter indicates the size of the value in bytes. The optional `noreply` parameter tells the server not to send a response.
**Example**: `set mykey 0 3600 5\r\nhello\r\n`
### GET
**Command**: `get <key>`
**Description**: Retrieves the value stored in the cache under the given key.
**Example**: `get mykey`
### DELETE
**Command**: `delete <key> [noreply]`
**Description**: Deletes the value stored in the cache under the given key. The optional `noreply` parameter tells the server not to send a response.
**Example**: `delete mykey`
## Advanced Commands
### INCR
**Command**: `incr <key> <value>`
**Description**: Increments the value stored in the cache under the given key by the specified amount. If the value is not numeric, an error is returned.
**Description**: Decrements the value stored in the cache under the given key by the specified amount. If the value is not numeric, an error is returned.
**Example**: `decr mykey 5`
### APPEND
**Command**: `append <key> <bytes> [noreply]`
**Description**: Appends the specified value to the value stored in the cache under the given key. The `bytes` parameter indicates the size of the value to be appended. The optional `noreply` parameter tells the server not to send a response.
**Example**: `append mykey 5\r\nworld\r\n`
### PREPEND
**Command**: `prepend <key> <bytes> [noreply]`
**Description**: Prepends the specified value to the value stored in the cache under the given key. The `bytes` parameter indicates the size of the value to be prepended. The optional `noreply` parameter tells the server not to send a response.
**Description**: Stores the specified value in the cache under the given key, but only if the value has not been modified since the last retrieval. The `cas_unique` parameter is a unique identifier for the value. The `flags`, `exptime`, and `bytes` parameters have the same meaning as in the `set` command. The optional `noreply` parameter tells the server not to send a response.
These are some of the basic and advanced commands available in Memcache. Understanding and utilizing these commands can greatly enhance your ability to work with Memcache and optimize the performance of your applications.
To determine the number of keys that exist in a Memcache server, you can use the `stats` command. This command provides statistics about the server, including the total number of keys stored.
This command will return a list of items with their corresponding statistics. Look for the line that starts with `STAT items:`, which indicates the total number of items (keys) stored in the Memcache server.
