Cassandra Day Chicago 2015: Building Java Applications with Apache Cassandra
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Transcript of Cassandra Day Chicago 2015: Building Java Applications with Apache Cassandra
An AwesomeDatabase
• Always on • Horizontally scalable • Mul5ple data centers • Cloud/hybrid • Web/mobile/IoT
tim name: Tim
role: teacher
kristenname: Kristen
role: marketing
billy role: CEO
matt name: Matt
role: founder
status: active
status: chill
CREATE TABLE product_browsing_data (product_id uuid, user_id uuid, clicked_at timestamp, serialized_browsing_data text, PRIMARY KEY (product_id, user_id, clicked_at) );
DataStax Java Driver
• Open source (ASL 2.0) • Where CQL happens • Ac5vely developed • Now faster than ThriK • Doesn’t make you want to die
apply plugin: 'java'repositories { jcenter()} dependencies { compile 'com.datastax.cassandra:cassandra-driver-core:2.1.2' testCompile 'org.testng:testng:6.8.8' testCompile 'junit:junit:4.11'}
Gradle Build
session.execute( "INSERT INTO sensor \ (sensor_id, reading, time) \ VALUES \ (24601, 2.171828, now())”);
ClusterInterfaceCluster cluster = Cluster.builder() .addContactPoints(“192.168.50.1”) .build(); Session session = cluster.connect(“IoT_keyspace");
ResultSet resultSet = session.execute("SELECT * FROM sensor");
List<Row> rows = resultSet.all();
for(Row row : rows) { String sensorId = row.getString("sensor_id" ); double reading = row.getDouble("reading" ); Date time = row.getDate("time" ); }
BasicQueries
PreparedStatement insertReading = session.prepare( "INSERT INTO sensor \ (sensor_id, reading, time) VALUES (?, ?, ?)” ); Statement statement = insertReading .bind(24601, 2.71828, new Date()) .setConsistencyLevel(ConsistencyLevel.QUORUM);
session.execute(statement);
PreparedStatements
ClusterInterface
Cluster cluster = Cluster.builder() .addContactPoints(“192.168.50.1”, “192.168.50.4”, “192.168.50.8”) .build();
Outsmar)ng Yourself• Pick one node • Send all coordina5on traffic to that node • Hey, maybe make it a fat node! • WhiteListPolicy • PLEASE DO NOT DO THIS
List<InetSocketAddress> whiteList = new ArrayList<InetSocketAddress>();whiteList.add(...);Cluster c = Cluster.builder().withLoadBalancingPolicy( new WhiteListPolicy( new RoundRobinPolicy(), whiteList)).build();
WhiteListing
apply plugin: 'java'repositories { jcenter()} dependencies { compile 'com.datastax.cassandra:cassandra-driver-core:2.1.2' compile 'com.datastax.cassandra:cassandra-driver-mapping:2.1.2' testCompile 'org.testng:testng:6.8.8' testCompile 'junit:junit:4.11'}
MapperObject
CREATE TABLE sensor ( sensor_id int, reading double, time timestamp );
MapperObject
@UDT(keyspace = "IoT_keyspace", name = "sensor") public class Sensor { private int sensorId; private double reading; private Date Time; // getters and setters elided with extreme prejudice...}
MapperObject
MappingManager manager = new MappingManager(session);Mapper mapper = manager.mapper(Sensor.class);Sensor reading = mapper.get("24601");
ResultSetFuture future = session.executeAsync("SELECT * FROM sensor");
// Returns immediately// Go do productive things here…// Then finally block on the results when you must
ResultSet futureResults = future.get();List<Row> rows = resultSet.all();
FutureResults
Executor executor = Executors.newCachedThreadPool();ResultSetFuture future = session.executeAsync("SELECT * FROM sensor");
future.addListener(new Runnable() { public void run() { // Do the things here… } }, executor);
FutureResults