[hibernate-dev] Cache region names are not prefixed in 5.3

[Gail Badner]

I see that HHH-11356 removed prefixes from region names used by Hibernate.

I also noticed that entity regions are unprefixed and the package name is
removed.

I've created 2 issues:
HHH-12599 to add Javadoc to make it clear that region names are unprefixed;
HHH-12598 to add the package onto entity region names.

Should I create an ISPN issue for hibernate-infinispan (or whatever it's
referred to now) to add the prefixes?

On Thu, May 17, 2018 at 4:55 AM, Sanne Grinovero <sanne at hibernate.org>
wrote:

> On 17 May 2018 at 12:09, Radim Vansa <rvansa at redhat.com> wrote:
> > I basically agree with Sanne here that having the prefix isolated opens
> > space for performance improvements, though if certain call is prefixed,
> > RegionFactory can always drop that prefix. The important thing is to
> mention
> > if the region name is prefixed or not in javadocs. I would also prefer if
> > *all* region names that RegionFactory is supposed to access followed the
> > same strategy (prefixed/not-prefixed).
> >
> > 5.1 included method
> >
> >     QueryResultsRegion buildQueryResultsRegion(String regionName,
> Properties
> > properties)
> >
> > where StandardQueryCache did the prefix for us, the change in 5.3 to
> >
> >     QueryResultsRegion buildQueryResultsRegion(String regionName,
> > SessionFactoryImplementor sessionFactory)
> >
> > does not indicate that the prefix won't be there and the javadoc is
> missing
> > completely.
> >
> > Also, DomainDataRegionConfig.getRegionName() has no javadoc and
> > RegionFactory does not add the prefix.
> >
> > @Steve could you please amend the javadoc and confirm if RF should prefix
> > region names?
> >
> > @Sanne while cache manager per deployment is an obvious way to
> distinguish
> > regions at deployments, CM holds some heavy resources (e.g. threads) - so I
> > while we are supposed to scale number of caches up to thousands (and
> we've
> > fixed some problems that arise when you have for example ~3k caches), ATM
> > you're not supposed to scale CMs. And I don't think that we'll focus in
> this
> > direction since the bright future lies in microservices :)
>
> Right, good points. It's a possible optimization I'd like to see
> eventually but it's not trivial to get there yet.
>
> Yet assuming a microservices scenario, this does become trivial to
> benefit from: the container knows there's a single deployment, a
> single CM. So no need to isolate them at all, just need to possibly
> isolate multiple PUs defined in the same service.
>
> So it will be easy to run hundreds of isolated microservices on the
> same physical CPU and kill each other via process contention :P
>
> >
> > Radim
> >
> >
> > On 05/17/2018 12:23 PM, Sanne Grinovero wrote:
> >>
> >> On 17 May 2018 at 11:11, Sanne Grinovero <sanne at hibernate.org> wrote:
> >>>
> >>> I think this is the RegionFactory's responsibility, as Hibernate ORM
> >>> alone can't know if this is necessary.
> >>>
> >>> Prefixing is one of many options to isolate caches; a Cache technology
> >>> might wish to use a different approach by implementing a custom
> >>> `org.hibernate.cache.spi.CacheKeysFactory`.
> >>
> >> Hum, I regret how I wrote the above paragraph.
> >>
> >> I actually meant that a Cache technology could implement isolation in
> >> many different ways.
> >> Using a custom `CacheKeysFactory` is just an example, there are many
> >> other options as well. In fact, I believe a good choice for
> >> application servers would be to have an independent CacheManager for
> >> each deployment. Then it can safely inspect the deployment, see if
> >> there are multiple Persistence Units using the same caching
> >> technology, and implement further isolation only if necessary.
> >>
> >> These thoughts are a consequence of a chat I had with Paul Ferraro
> >> from the WildFly team, as he mentioned the size of the keys becoming
> >> problematic with all the additional prefixing they need to apply. I
> >> hope this will make it possible to e.g. create an "as small as
> >> possible" unique identifier for the deployments to replace the
> >> deployment name during serialization (to identify the CacheManager)
> >> followed by a numeric id indexing the PUs within the deployment - or
> >> nothing altogether in case of single PUs.
> >>
> >> Of course, I don't expect that to be needed right away; the
> >> RegionFactory could just do good old prefixing for now but I hope
> >> we'll explore such improvements in the near future.
> >>
> >> Thanks,
> >> Sanne
> >>
> >>> Not least the server / deployer might be able to hint the Cache
> >>> provider to tell if isolation is at all necessary.
> >>>
> >>> In conclusion, by having Hibernate ORM not messing with prefixes
> >>> allows other technologies to implement more efficient solutions. Our
> >>> own code also ends up being more efficient by not needing to add a
> >>> prefix during each and every access to the cache.
> >>>
> >>> Thanks,
> >>> Sanne
> >>>
> >>> On 17 May 2018 at 06:34, Gail Badner <gbadner at redhat.com> wrote:
> >>>>
> >>>> I see that cache region names are not being prefixed in 5.3.
> >>>>
> >>>> EnabledCaching sets the TimestampsRegion region name
> >>>> to TimestampsRegion.class.getName(), and sets the QueryResultsRegion
> >>>> region
> >>>> name to QueryResultsRegion.class.getName(). [1]
> >>>>
> >>>> Without a prefix, WildFly is failing intermittently when there are 2
> >>>> persistence units with the query cache enabled due to:
> >>>>
> >>>> org.infinispan.commons.CacheConfigurationException: ISPN000453:
> Attempt
> >>>> to
> >>>> define configuration for cache org.hibernate.cache.spi.
> TimestampsRegion
> >>>> which already exists
> >>>>
> >>>> Entity region names are not being prefixed either.
> >>>>
> >>>> Should they be prefixed by Hibernate or by the RegionFactory?
> >>>>
> >>>> Regards,
> >>>> Gail
> >>>>
> >>>> [1]
> >>>>
> >>>> https://github.com/hibernate/hibernate-orm/blob/master/
> hibernate-core/src/main/java/org/hibernate/cache/internal/
> EnabledCaching.java#L80-L92
> >>>> _______________________________________________
> >>>> hibernate-dev mailing list
> >>>> hibernate-dev at lists.jboss.org
> >>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
> >
> >
> >
> > --
> > Radim Vansa <rvansa at redhat.com>
> > JBoss Performance Team
> >
>