keycloak-scim/docbook/auth-server-docs/reference/en/en-US/modules/cache.xml

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<chapter id="server_cache">
    <title>Server Cache</title>
    <para>
        By default, Keycloak caches realm metadata and users.  There are two separate caches, one for realm metadata
        (realm, application, client, roles, etc...) and one for users.  These caches greatly improves the performance of the server.
    </para>

    <section>
        <title>Disabling Caches</title>
        <para>
            The realm and user caches can be disabled through configuration or through the management console.  To
            manally disable the realm or user cache, you must edit the <literal>keycloak-server.json</literal> file
            in your distribution.  Here's what the config looks like initially.
        </para>
        <para>
            <programlisting><![CDATA[
    "realmCache": {
        "provider": "${keycloak.realm.cache.provider:mem}"
    },

    "userCache": {
        "provider": "${keycloak.user.cache.provider:mem}",
        "mem": {
            "maxSize": 20000
        }
    },
]]></programlisting>
        </para>
        <para>You must then change it to:
            <programlisting><![CDATA[
    "realmCache": {
        "provider": "${keycloak.realm.cache.provider:none}"
    },

    "userCache": {
        "provider": "${keycloak.user.cache.provider:none}"
    },
]]></programlisting>
        </para>
        <para>
           You can also disable either of the caches at runtime through the Keycloak admin console Realm Settings page.
           This will not permanently disable the cache.  If you reboot the server, the cache will be re-enabled unless
            you manualy disable the cache in the <literal>keycloak-server.json</literal> file.
        </para>
    </section>
    <section>
        <title>Clear Caches</title>
        <para>
            To clear the realm or user cache, go to the Keycloak admin console Realm Settings->Cache Config page.  Disable the cache
            you want.  Save the settings.  Then re-enable the cache.  This will cause the cache to be cleared.
        </para>
    </section>
    <section>
        <title>Cache Config</title>
        <para>
            Cache configuration is done within <literal>keycloak-server.json</literal>.  Changes to this file will not
            be seen by the server until you reboot.  Currently you can only configure the max size of the user cache.
            <programlisting><![CDATA[
    "userCache": {
        "provider": "${keycloak.user.cache.provider:mem}",
        "mem": {
            "maxSize": 20000
        }
    },
]]></programlisting>
        </para>
    </section>
</chapter>