Re: [hibernate-dev] HHH-13916 / WFLY-13259

Hi Gail, I would go ahead with this improvement for ORM 6 and avoid spending your precious time on a v5 improvement - especially if it's going to require coordination with both the Infinispan and WildFly teams. Thanks On Fri, 10 Apr 2020 at 00:56, Gail Badner <gbadner(a)redhat.com&gt; wrote: > > I've been looking into how to fix this issue: > > https://hibernate.atlassian.net/browse/HHH-13916 > https://issues.redhat.com/browse/WFLY-13259 > > The crux of the matter is when Hibernate calls CacheHelper.fromSharedCache( > session, cacheKey, cachAccess ), and the entity is not found in the cache, > Infinispan stores a PendingPut containing a > SharedSessionContractImplementor instance. > > IIUC, as an optimization, Infinispan assumes that the entity not found in > the cache will ultimately be added to the cache after it is loaded from the > database. If that doesn't happen, the PendingPut will expire and will > eventually be removed. Until it expires, > the SharedSessionContractImplementor instance cannot be garbage-collected. > > This is particularly a problem if the cache is not disabled while a large > amount of cacheable data is being imported. This is the particular use case > described by WFLY-13259. There is a reproducer attached that > throws OutOfMemoryError. > > The obvious workaround is to set org.hibernate.CacheMode.IGNORE (or > possibly CacheMode.PUT?) while importing data. > > I discussed this briefly with Sanne, and we agree that an improvement would > be to not store a SharedSessionContractImplementor in a PendingPut at all. > > There is already a way to get a UUID for the session by calling > SharedSessionContractImplementor#getSessionIdentifier(). Unfortunately, the > implementation in AbstractSharedSessionContract indicates that frequent > "UUID generations will cause a significant amount of contention". > > Sanne has suggested returning a "token" that is just a new Object. I've > created a branch > <https://github.com/gbadner/hibernate-core/tree/HHH-13916_token> [1] that > does this. > > Infinispan would need to be updated so that PendingPut#owner is set > to SharedSessionContractImplementor#getSessionToken() (instead of > the SharedSessionContractImplementor object). > > Looking at the Infinispan code, I see that code that would be affected is > in > org.infinispan.hibernate.cache.commons.access.PutFromLoadValidator, which > is used by infinispan-hibernate-cache-v51. > > IIUC, in order to fix this any time soon for WildFly or EAP 7.x, [1] would > have to be backported to both Hibernate ORM 5.1 and 5.3 branches, and the > Hibernate versions would have to be updated in Infinispan before Infinispan > could be updated to use SharedSessionContractImplementor#getSessionToken(). > > Galder/Radim, are there any plans for > dropping infinispan-hibernate-cache-v51? > > Are there other places where the SharedSessionContractImplementor is stored > in the cache? > > Aside from infinispan-hibernate-cache-v51, do you see anything about [1] > that would cause problems? > > If not, when do you think we could coordinate this change? Do we need to > wait for Hibernate ORM 6.0? > > This is considered an improvement, so it's not urgent. It would be nice to > fix this though. > > Galder/Radim, please provide your input so we figure out when it can be > fixed. > > Thanks, > Gail > > [1] https://github.com/gbadner/hibernate-core/tree/HHH-13916_token > [2] > _______________________________________________ > hibernate-dev mailing list > hibernate-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/hibernate-dev >