[keycloak-dev] Performance improvements with large number of realms

[Stian Thorgersen]

On a quick glance these changes (1, 2 and 3) seems all to make sense, but
there's a lot of them and we just don't have the capacity to review and
incorporate for 2.x (we're only weeks away from last 2.x release) so I
think it'll have to wait for 3.x.

4 and 5 have been significantly reworked so please review 2.4.0.Final and
see if this release fixed issues around caching.


On 17 November 2016 at 01:43, Gabriel Lavoie <glavoie at gmail.com> wrote:

> Hi,
>      following
> http://lists.jboss.org/pipermail/keycloak-user/2016-October/008032.html
> that was discussed in the keycloak-user mailing list, I've been working in
> the last few weeks on fixing performance issues for Keycloak setup with a
> very large number of realms (tested with 500-600). As suggested by Stian, I
> have changes to submit as pull requests that I want to discuss here first
> to make sure they are acceptable.
>
> With this improvements, the following issues were solved in our setup:
> - Startup time reduced from more than 15 minute to under a minute.
> - Login time to the admin console reduced from ~5 minutes to ~20 secs when
> cache is being filled, to under 5 when cache is filled.
> - Realm creation time reduced from ~1 minute to under 10 secs.
>
> 1 - Too many autoFlush checks by Hibernate and explicit em.flush():
> >From what I see, the JPA entity model is very disconnected and many
> entities are retrieved through their ID using NamedQuery. I'm not sure why
> the mapping was done this way.
>
> This causes Hibernate to make a autoFlush check for dirty entities on every
> query, which is very CPU intensive. There are a few entities that can
> benefit from having a Collection/Set to their child entities and use it
> rather than a query to retrieve the required information. Also, with
> explicit mapping, I foresee multiple explicit em.flush() that could be
> removed when changing the data.
>
> In this changeset I've covered only what was necessary for us, but there
> are still a few areas that could be improved in my opinion:
>
> https://github.com/glavoie/keycloak/commit/93c8056498e38ed075523f5b9b78db
> de2814d783


>
>
> 2 - Many missing index for FKs:
> We are using an Oracle database and indexes are not created automatically
> for FKs. I've added many but I'm not 100% sure if you want a new Liquibase
> changeset for every changes that could go in a version or only one per
> version. I still have one index to fix so don't take this as-is for now:
>
> https://github.com/glavoie/keycloak/commit/7bb44b7dfeea31e663695218524a0d
> a4ce48a331
>
> 3 - Using Set rather than Collection with JPA entities:
> When using a Collection, Hibernate will delete all rows and re-insert them
> in the join table to update the content. This behavior was very slow and
> visible with the "admin" composite role that points to roles for all realms
> (through the different clients). This was slowing down a lot new realm
> creation. When using a Set, Hibernate does a better job at tracking
> changes.
>
> https://github.com/glavoie/keycloak/commit/9eb1bf013e80395affeec09625d5ee
> 6157a7084a
>
>
> 4 - "session" cache when testing for "hasRole" with a composite role:
> The recursive search done KeycloakModelUtils.searchFor() can generate quite
> a lot of hits on the Infinispan cache when trying to test for role. With
> 500 realms, we saw up to 1.5 millions hits on the realmsRevision cache just
> to login to the admin console. I've added a in-memory cache of the
> retrieved composite RoleModel list in the Infinispan RoleAdapter. As I
> understand, every instance of a RoleAdapter is bound to a KeycloakSession
> that can be seen as a transaction/request. Still relying on the delegate
> object if the RealmAdapter is being invalidated.
>
> This is the change that reduced the most the login time to the admin
> console or the time to obtain a Bearer token for the admin API:
>
> https://github.com/glavoie/keycloak/commit/0ab39670525315148761627e7d0f80
> 8d4ef9c3c0
>
>
> 5 - realmRevisions cache size:
> In https://issues.jboss.org/browse/KEYCLOAK-3202, the realmRevisions cache
> creation was moved from standalone.xml to Java code. With our current
> Keycloak cluster we already added the eviction policy mentioned in the
> ticket, but had to increase the size to 50000 to support our number of
> realms. Having this size hardcoded in the Java code becomes a bit
> inconvenient with the latest versions.
>
> I didn't really fix the code as Stian mentioned that this part is being
> heavily reworked. I would guess this has something to do with
> http://lists.jboss.org/pipermail/keycloak-dev/2016-November/008397.html?
>
> https://github.com/glavoie/keycloak/commit/6e3e7e8400da3440a743941980bad3
> dc83be7965
>
>
> Thank you!
>
> Gabriel
>
> --
> Gabriel Lavoie
> glavoie at gmail.com
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