Memcached telnet command summary

Here a summary of Memcached commands usable in telnet
If you need to install or set up Memcached as a service on Windows, follow this link

Connecting to Memcached server with telnet

In the following \r\n mean you have to type enter in telnet console
If Memcached server send ERROR or CLIENT_ERROR, something is false with the command, if it’s SERVER_ERROR, server itself is in trouble

Retrieval Commands

Parameters :
<key> : the key of the data stored to retrieve
<key>* mean you can request value of multiple keys separated by whitespace

These commands return :
VALUE <flag> <bytes>\r\n<data> (see the following for explanation of <bytes> and <flag>)
END indicate the end of response

Get

Get value from key
Telnet command : get <key>*\r\n

Gets

Get value from key along with a cas token (to use with cas command)
Telnet command : gets <key>*\r\n

Storage Commands

Parameters :
<key> : the key of the data stored
<flags> : 32-bit unsigned integer that the server store with the data (provided by the user), and return along the data when the item is retrieved
<exptime> : expiration time in seconds, 0 mean no delay, if exptime is superior to 30 day, Memcached will use it as a UNIX timestamps for expiration
<bytes> : number of bytes in the data block
<cas unique> : unique 64-bit value of an existing entry (retrieved with gets command) to use with cas command
[noreply] : optional parameter that inform the server to not send the reply

These commands can return :
STORED to indicate success
NOT_STORED indicate that the data was not stored because condition for “add” or “replace” command wasn’t met, or the item is in a delete queue
EXISTS indicate that the item you are trying to store with “cas” command has been modified since last fetch
NOT_FOUND indicate that the item did not exist or has been deleted

Set

Store key/value pair in Memcached

Telnet command : set <key> <flags> <exptime> <bytes> [noreply]\r\n<value>\r\n

Add

Store key/value pair in Memcached, but only if the server doesn’t already hold data for this key

Telnet command : add <key> <flags> <exptime> <bytes> [noreply]\r\n<value>\r\n

Replace

Store key/value pair in Memcached, but only if the server already hold data for this key

Telnet command : replace <key> <flags> <exptime> <bytes> [noreply]\r\n<value>\r\n

Append

Add value to an existing key after existing data
Append does not take <flags> or <exptime> parameters but you must provide them !

Telnet command : append <key> <flags> <exptime> <bytes> [noreply]\r\n<value>\r\n

Prepend

Add value to an existing key before existing data
Prepend does not take <flags> or <exptime> parameters but you must provide them !

Telnet command : prepend <key> <flags> <exptime> <bytes> [noreply]\r\n<value>\r\n

Cas

Store data only if no one else has updated since the last fetch, determined with the cas tokem from gets command
Telnet command : cas <key> <flags> <exptime> <bytes> <cas unique> [noreply]\r\n

Delete Command

Parameters :
<key> : the key to delete
[<time>] : optional time in second before real deletion of item
[noreply] : optional parameter that inform the server to not send the reply

These command can return :
DELETED to indicate success
NOT_FOUND indicate that the item did not exist or has been deleted

Delete

Store key/value pair in Memcached

Telnet command : delete <key> [<time>] [noreply]\r\n

Increment/Decrement Commands

Parameters :
<key> : the key to delete
<value> : the amount to increase/decrease the item.
[noreply] : optional parameter that inform the server to not send the reply

These command can return :
NOT_FOUND indicate that the item did not exist or has been deleted
<value> increment and decrement return the result

Increment

Increment value associated with key in Memcached, item must exist, increment command will not create it
The limit of increment is the 64 bit mark

Telnet command : incr <key> <value> [noreply]\r\n

Decrement

Decrement value associated with key in Memcached, item must exist, decrement command will not create it
If you try to decrement a value bellow 0, value will stay at 0

Telnet command : decr <key> <value> [noreply]\r\n

Touch Command

Parameters :
<key> : the key to delete
<exptime> : is expiration time. Works the same as with the update commands (set/add/etc). This replaces the existing expiration time.
[noreply] : optional parameter that inform the server to not send the reply

These command can return :
NOT_FOUND indicate that the item did not exist or has been deleted
TOUCHED to indicate success

Touch

The “touch” command is used to update the expiration time of an existing item without fetching it.

Telnet command : touch <key> <exptime> [noreply]\r\n

Statistics Commands

Parameters :
<args> : argument to stats command

These command can return various stats that we will explain in the following

Basic stats

Return general-purpose statistics like uptime, version, memory occupation, …

Telnet command : stats\r\n

Items stats

Return items statistics, will display items statistics (count, age, eviction, …) organized by slabs ID

Telnet command : stats items\r\n

Slabs stats

Return slabs statistics, will display slabs statistics (size, memory usage, commands count, …) organized by slabs ID

Telnet command : stats slabs\r\n

Misc Commands

Flush_all

Flush the server key/value pair (invalidating them) after a optional [<time>] period
It always return OK

Telnet command : flush_all [<time>] [noreply]\r\n

Version

Return the Memcached server version

Telnet command : version\r\n

Verbosity

Change the verbosity ouptut of Memcached server
It always return OK

Telnet command : verbosity <level> [noreply]\r\n

Quit

Server close connection when receiving this command

Telnet command : quit\r\n

For any advanced need Memcached text protocol can be found here

Other Memcached Resources

You can find a lot of Memcached resources on this Memcached resources page.

2 Responses

  1. Binh Thanh Nguyen says:

    Thanks so much

  2. w3bc0d3r says:

    Thnx Good Site!
    Here is my simple memcached cLass on PHP https://github.com/w3bc0d3r/memcached

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