@dbrimley#DevoxxHazelcast

High Performance In-Memory Java with Open Source

David Brimley @dbrimley http://blog.hazelcast.com/ http://www.hazelcast.org/

@dbrimley#DevoxxHazelcast

Who is this guy?

• Senior Solutions Architect for Hazelcast.

• 17 Years Java Development.

• Started out as a Cobol Programmer in 1988.

• Learnt to code Basic on a Vic-20 and BBC Model B.

• Oracle Coherence and Pivotal Gemfire.

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In Memory Java

• High Performance In Memory Java? It’s an IMDG!

• Getting to grips with Hazelcast, a tour of features.

• Some IMDG Tips!

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In Memory Java

• It’s 2 things really, the 2 C.

• Cache

• Compute

• The Magic is the D you stick in front…Distributed!

• DCache + DCompute = IMDG!

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Evolution of IMDG

CACHE IN ONE PROCESS - A MAP, AGGHH OOM!

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Evolution of IMDG

CACHE IN ONE PROCESS - WITH EVICTION

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Evolution of IMDG

DISTRIBUTED CACHE

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Evolution of IMDG

DISTRIBUTED COMPUTE

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Evolution of IMDG

BIG DATA IMDG

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Qualities of an IMDG

• It should be easy to scale, vertically and horizontally.

• It should be fault tolerant.

• It should be performant.

• It should have a easy to understand API.

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Enter Hazelcast!• Java Collections & Queues - Distributed!

• Java Concurrency - Distributed!

• Persist to and Read from from Anything!(RDBMS,File,Hadoop,Cassandra,MongoDB)

• Predicate and SQL like queries!

• Topics(Pub/Sub)

• Rich Event Callbacks

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<dependency> <groupId>com.hazelcast</groupId> <artifactId>hazelcast</artifactId> <version>3.2.2</version> </dependency>

1. Starting a Hazelcast Cluster Node

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HazelcastInstance hz = Hazelcast.newHazelcastInstance();

2. Starting a Hazelcast Cluster Node

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Demo

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Distributed Compute

• Executors

• EntryProcessor

• MapReduce

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Executor can run anywhere

• IExecutorService

• Runnable or Callable

• Targeted execution in the grid (keys,members)

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HazelcastInstance hz = Hazelcast.newHazelcastInstance(); IExecutorService executor = hz.getExecutorService(“myEService");executor.execute(new EchoTask("foo"));

2. Java Executor, but Distributed!

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EntryProcessor

• Execute your code on an entry in an atomic way.

• You do not need any explicit lock on entry.

• Runs via IMap.

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/** * Applies the user defined EntryProcessor to the entry mapped by the key. * Returns the the object which is result of the process() method of EntryProcessor. */

Object executeOnKey(K key, EntryProcessor entryProcessor);

EntryProcessor via IMap

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MapReduce

• New in 3.2

• Hadoop like API.

• Aggregators in 3.3

• Scheduled Tasks in 3.4

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IMap<String,String> map = hazelcastInstance.getMap("articles");

KeyValueSource<String,String> source = KeyValueSource.fromMap(map);

Job<String, String> job = jobTracker.newJob( source );

ICompletableFuture<Map<String, Long>> future = job .mapper( new TokenizerMapper() ) .combiner( new WordCountCombinerFactory() ) .reducer( new WordCountReducerFactory() ) .submit();

MapReduce

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Persist and Read from anywhere.

• Implement a MapStore interface.

• Configure your Map.

• Cache misses will read through to the store.

• Cache updates can persist to store (sync/async).

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<map name="aDistributedMap"> <map-store enabled="true"> <class-name>com.company.YourMapStore</class-name> <write-delay-seconds>30</write-delay-seconds> </map-store> <indexes> <index ordered="true">aValueProperty</index> </indexes> </map>

2. Configure (in XML,Spring or API)

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public class UserMapStore implements MapStore<Integer, User> {

public void store(Integer userKey, User user) { userDao.insertUser(user); } public User load(Integer userKey) { return userDao.getUser(userKey); }

…… (more methods like delete, loadAll)

2. Implement MapStore

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We like standards.

• Greg Luck, Hazelcast CTO is JSR107 co-spec lead.

• Hazelcast will be JSR107 compliant this summer.

• https://github.com/hazelcast/hazelcast/tree/jcache-preview

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Demo

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Some IMDG Advice

• Don’t force in your RDBMS schema.

• Do you really need that transaction?

• Execute near the data.

• Use the right Serialisation interface.

• Tune your JVM.

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Summar

y

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Powerful tool for many Use Cases

• Unscalable NoSQL or RDBMS fix.

• Compute Intensive Tasks

• Web Session Replication

• HA Services

• WAN Replication

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Get Coding!

• hazelcast.org - for open source and downloads

• hazelcast.com - for pro support,papers & webinars

• github.com/hazelcast for sources

• github.com/hazelcast/hazelcast-code-samples

• follow me on twitter @dbrimley

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Q & A

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Thanks / Creative Commons

•Presentation Template — Guillaume LaForge

•The Queen — A prestigious heritage with some inspiration from The Sex Pistols and funny Devoxxians

•Girl with a Balloon — Banksy

•Tube — Michael Keen