Off Heap enhancements

The off heap implementation in Infinispan has become much more widely used since its introduction. There have been some issues and improvements identified to get this storage type more in line with its heap counterpart. For those of you that are unware the off-heap setting is actually only "off" the JVM heap and still resides in the native memory of the application.

The best part of all the below changes is the user does not need to change anything, other than configuring Off Heap storage.

Resizing Off Heap Container

For those of you that have used/configured off heap storage before you may have noticed that there was a configuration option named address count. This setting allowed you to configure how many address pointers the container had. You can think of this as essentially how many buckets you have in a HashMap. Unfortunately the number of pointers was fixed and therefore the user would have to know how many elements they expected to have.

This setting also had another problem. If the user required a larger size of elements this would increase startup time as the container can be iterated upon multiple times when it is empty. Iterating over a container of one million empty pointers would be much slower than iterating over one of only 1024 for example.

I am glad to say as of Infinispan 10.0.0.Final this setting and the performance of iteration have been greatly improved.

Configuration

The address count variable is now ignored and instead the off heap based container will start at smaller amount of "buckets" in the range of 128 or 256. We then apply a load factor of .75, which means we will automatically increase the size of the underlying "buckets" once we have inserted a number of entries being 75% or larger than the current "bucket" size.

The resize operation will grow to have double the amount of "buckets" it had prior. The resize operation will be performed concurrently with other operations, providing minimal blocking as we have locks equal to the number of CPUs times two.

This will allow for a cache with off heap to be started significantly faster and relieves some configuration options that were unneeded. Note that the map, just like a java.util.HashMap, will not decrease the number of "buckets" once it grows to a given size.

Iteration changes

I mentioned that iteration was slower during startup of larger number of "buckets". This was due to it possibly having a large number of them, however it was also plauged by an ineffecient way of iterating over them. In addition to rewriting the resize operation, we have also optimized the memory layout so that "buckets" can be iterated sequentially which provides more mechanical sympathy.

Hash changes

This one is rather short and sweet, but the old hash algorithm we used would cause too many collisions for objects that had hash functions that returned values in a similar range, such as java.lang.Integer and java.util.String (with shared startubg characters).

Therefore it has been changed to provide a bit better spreading. This is part of ISPN 10.0.0.Final.

Expiration bugs

Unfortunately off heap had a few issues with expiration. It didn’t support max idle and expiration metadata was not properly transferred to new nodes during state transfer.

In addition to max idle algorithm being rewritten, Off heap now properly supports max idle as of 10.1.4.Final and 11.0.0.Final.

Off heap metadata transferred to new nodes has been fixed in 10.1.8.Final and 11.0.0.Final.

News

Tags

JUGs alpha as7 asymmetric clusters asynchronous beta c++ cdi chat clustering community conference configuration console data grids data-as-a-service database devoxx distributed executors docker event functional grouping and aggregation hotrod infinispan java 8 jboss cache jcache jclouds jcp jdg jpa judcon kubernetes listeners meetup minor release off-heap openshift performance presentations product protostream radargun radegast recruit release release 8.2 9.0 final release candidate remote query replication queue rest query security spring streams transactions vert.x workshop 8.1.0 API DSL Hibernate-Search Ickle Infinispan Query JP-QL JSON JUGs JavaOne LGPL License NoSQL Open Source Protobuf SCM administration affinity algorithms alpha amazon annotations announcement archetype archetypes as5 as7 asl2 asynchronous atomic maps atomic objects availability aws beer benchmark benchmarks berkeleydb beta beta release blogger book breizh camp buddy replication bugfix c# c++ c3p0 cache benchmark framework cache store cache stores cachestore cassandra cdi cep certification cli cloud storage clustered cache configuration clustered counters clustered locks codemotion codename colocation command line interface community comparison compose concurrency conference conferences configuration console counter cpp-client cpu creative cross site replication csharp custom commands daas data container data entry data grids data structures data-as-a-service deadlock detection demo deployment dev-preview devnation devoxx distributed executors distributed queries distribution docker documentation domain mode dotnet-client dzone refcard ec2 ehcache embedded query equivalence event eviction example externalizers failover faq final fine grained flags flink full-text functional future garbage collection geecon getAll gigaspaces git github gke google graalvm greach conf gsoc hackergarten hadoop hbase health hibernate hibernate ogm hibernate search hot rod hotrod hql http/2 ide index indexing india infinispan infinispan 8 infoq internationalization interoperability interview introduction iteration javascript jboss as 5 jboss asylum jboss cache jbossworld jbug jcache jclouds jcp jdbc jdg jgroups jopr jpa js-client jsr 107 jsr 347 jta judcon kafka kubernetes lambda language leveldb license listeners loader local mode lock striping locking logging lucene mac management map reduce marshalling maven memcached memory migration minikube minishift minor release modules mongodb monitoring multi-tenancy nashorn native near caching netty node.js nodejs nosqlunit off-heap openshift operator oracle osgi overhead paas paid support partition handling partitioning performance persistence podcast presentations protostream public speaking push api putAll python quarkus query quick start radargun radegast react reactive red hat redis rehashing releaase release release candidate remote remote events remote query replication rest rest query roadmap rocksdb ruby s3 scattered cache scripting second level cache provider security segmented server shell site snowcamp spark split brain spring spring boot spring-session stable standards state transfer statistics storage store store by reference store by value streams substratevm synchronization syntax highlighting testing tomcat transactions uneven load user groups user guide vagrant versioning vert.x video videos virtual nodes vote voxxed voxxed days milano wallpaper websocket websockets wildfly workshop xsd xsite yarn zulip
Posted by William Burns on 2020-06-09
Tags: off-heap storage
back to top