Memcached replace command

The Memcached replace command replaces the value of the key (key) that already exists.

If key does not exist, the replacement fails and you will get a response NOT_STORED .

Grammar:

The basic syntax of the replace command is as follows:

replace key flags exptime bytes [noreply]
value

The parameters are described below:

• Key: Key in the key-value structure to find cached values.
• flags: You can include integer parameters for key value pairs, which the client uses to store additional information about key value pairs.
• exptime: The length of time (in seconds, 0 means forever) to save key pairs in the cache
• Bytes: The number of bytes stored in the cache
• Noreply (optional): This parameter tells the server that no data needs to be returned
• value: Stored value (always on the second row) (can be understood directly as value in key-value structure)

Instance

In the following example we set:

• key → mykey
• flag → 0
• exptime → 900 (in seconds)
• Bytes → 10 (bytes of data storage)
• value → data_value

In the following example we use the key bit 'mykey' and store the corresponding value data_value. After execution we replace the value of the same key as 'some_other_value'.

add mykey 0 900 10
data_value
STORED
get mykey
VALUE mykey 0 10
data_value
END
replace mykey 0 900 16
some_other_value
get mykey
VALUE mykey 0 16
some_other_value
END

Output

If the data is added successfully, the output:

STORED

Output information description:

• STORED: The output after the successful save.
• NOT_STORED: Output after replacement failure.