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

[Gail Badner]

On Thu, May 17, 2018 at 5:24 PM, Gail Badner <gbadner at redhat.com> wrote:

> 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.
>

Actually, the package names are being included in the region names. The
test I was looking at did not have a package.


>
> 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.
>

I've rejected HHH-12598.


>
> 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.Timest
>> ampsRegion
>> >>>> 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/hiber
>> nate-core/src/main/java/org/hibernate/cache/internal/Enabl
>> edCaching.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
>> >
>>
>
>