Comment 9 for bug 1582585

Reviewed: https://review.openstack.org/328820
Committed: https://git.openstack.org/cgit/openstack/keystone/commit/?id=53bb53a814324234aa4b798651a616e310396221
Submitter: Jenkins
Branch: master

commit 53bb53a814324234aa4b798651a616e310396221
Author: liuhongjiang <email address hidden>
Date: Mon Jun 13 08:11:16 2016 +0800

    Added cache for id mapping manager

    When using a identity driver without providing uuid, and using default
    sql id mapping driver, if there are lots of users, then it may take
    minutes to list users. Adding cache to the id mapping manager can
    improve the performance.

    After adding the cache, when listing 12000 users though the keystone
    api, and the time is reduced from about 75 seconds to 20 seconds.

    Closes-Bug: #1582585
    Change-Id: I72eeb88926d8babb09a61e99f6f594371987f393