8:43 a.m.
On 18/02/16 08:07, Stian Thorgersen wrote:
Having two many joins (fetching everything about a realm in one
query)
is probably going to be bad for performance, especially if there are
loads of clients and roles. There can also be large difference between
different vendors.
Maybe clients and roles (and groups?) shouldn't be loaded
eagerly with
realm, but I guess most of the other stuff can be (ie. federation
providers, identity providers, SMTP configurations etc). Also for
clients we can eagerly load most of the stuff (ie. redirectUris, scopes
). ATM we eagerly preload whole realm in CachedRealm constructor, but we
have fetchType.LAZY everywhere. IMO this is not optimal and would mean
lot of SQL at startup during realm preload (I did not doublecheck myself).
Marek
Another thing in the future we should separate clients out into a
separate store. There could be thousands of clients or even more. So
they should be treated in a similar fashion to users. Does that have
impact on how we improve/refactor/fix caching now?
On 17 February 2016 at 21:56, Bill Burke <bburke(a)redhat.com
<mailto:bburke@redhat.com>> wrote:
On 2/17/2016 3:09 PM, Marek Posolda wrote:
> On 17/02/16 18:11, Bill Burke wrote:
>> Currently, adding or deleting a client, or updating a realm causes
>> invalidation/eviction of the realm and all clients in that realm. To
>> make matters worse, the next time the realm is accessed, it queries and
>> loads each client and its relationships. Why do we do this? When a
>> realm invalidation happens, the cache has no idea if the realm is just
>> being updated or removed entirely from the DB. With a realm removal, you
>> also need to evict the cache of all clients within the realm. So, a
>> cached realm MUST have a list of all clients within it. As a result,
>> the more clients that get added, keycloak gets slower and slower.
>> Eventually though the cache stabilizes after inserts/update/deletes
>> subside and we get back to normal performance, but you can see a nasty
>> blip for a little bit.
> We don't need to eagerly preload all clients when realm is
> loaded. Infinispan has streaming/predicate API and we are using
> it in many places (see InfinispanUserSessionProvider and all the
> stuff in package org.keycloak.models.sessions.infinispan.stream
> ). So when entry is invalidated, we can have cacheListener, which
> will query infinispan to return all cached clients of the realm
> and remove them. I can see that we already have listener. So
> possibly we can just change this line to use predicate query:
>
https://github.com/keycloak/keycloak/blob/master/model/infinispan/src/mai...
>
>
Lol, i was sort of kind of doing that doing cache.values(). This
makes it much easier with much less refactoring.
> Other option is, that we can try to optimize eager preload and
> see if we can reduce number of SQL queries at startup. For
> example, it seems that CachedClient constructor sends SQL query
> to preload just realm roles. And then each client sends another
> SQL query to preload his client roles (method
> CachedClient.cacheRoles ). Couldn't we instead send one SQL query
> to load all roles of realm (both realm and client roles)? Maybe
> we can even send one big SQL query to load realm with all it's
> objects :-) Possibly some FetchType.EAGER in Hibernate entities
> could help here.
>
yeah, we should start looking into stuff like this. We can at
least reduce the number of sql calls for caching a client or realm
individually. I'm not sure how feasible it is though or how much
better it is. Realms and clients contain more than a few one to
many relationships which would make the query result HUGE if I
remember how joins work.
--
Bill Burke
JBoss, a division of Red Hat
http://bill.burkecentral.com
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