[[modules-memcached]]
== memcached

The memcached module allows to expose *elasticsearch*
APIs over the memcached protocol (as closely
as possible).

It is provided as a plugin called `transport-memcached` and installing
is explained
https://github.com/elasticsearch/elasticsearch-transport-memcached[here]
. Another option is to download the memcached plugin and placing it
under the `plugins` directory.

The memcached protocol supports both the binary and the text protocol,
automatically detecting the correct one to use.

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=== Mapping REST to Memcached Protocol

Memcached commands are mapped to REST and handled by the same generic
REST layer in elasticsearch. Here is a list of the memcached commands
supported:

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==== GET

The memcached `GET` command maps to a REST `GET`. The key used is the
URI (with parameters). The main downside is the fact that the memcached
`GET` does not allow body in the request (and `SET` does not allow to
return a result...). For this reason, most REST APIs (like search) allow
to accept the "source" as a URI parameter as well.

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==== SET

The memcached `SET` command maps to a REST `POST`. The key used is the
URI (with parameters), and the body maps to the REST body.

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==== DELETE

The memcached `DELETE` command maps to a REST `DELETE`. The key used is
the URI (with parameters).

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==== QUIT

The memcached `QUIT` command is supported and disconnects the client.

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=== Settings

The following are the settings the can be configured for memcached:

[cols="<,<",options="header",]
|===============================================================
|Setting |Description
|`memcached.port` |A bind port range. Defaults to `11211-11311`.
|===============================================================

It also uses the common
<<modules-network,network settings>>.

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=== Disable memcached

The memcached module can be completely disabled and not started using by
setting `memcached.enabled` to `false`. By default it is enabled once it
is detected as a plugin.
