Cassandra summit 2013 - DataStax Java Driver Unleashed!
4 likes3,474 views
This document provides an overview of the DataStax Java Driver and how to use it to connect to and query Cassandra. It introduces key concepts like CQL, the data model, asynchronous operations, prepared statements, load balancing, and retry policies. The document also includes code examples for connecting to Cassandra, performing basic read and write operations using CQL strings and prepared statements, and more advanced techniques like asynchronous reads, query builders, custom load balancing policies, and object mapping.
![contactPoints = {“10.0.0.1”,”10.0.0.2”}
keyspace = “videodb”
public VideoDbBasicImpl(List<String> contactPoints, String keyspace) {
cluster = Cluster
.builder()
.addContactPoints(
! contactPoints.toArray(new String[contactPoints.size()]))
.build();
session = cluster.connect(keyspace);
}
Creating a Basic Connection](https://image.slidesharecdn.com/cassandrasummit-datastaxjavadriver-130613113240-phpapp01/85/Cassandra-summit-2013-DataStax-Java-Driver-Unleashed-13-320.jpg)
![contactPoints = {“10.0.0.1”,”10.0.0.2”}
keyspace = “videodb”
public VideoDbBasicImpl(List<String> contactPoints, String keyspace) {
cluster = Cluster
.builder()
.addContactPoints(
! contactPoints.toArray(new String[contactPoints.size()]))
.withLoadBalancingPolicy(Policies.defaultLoadBalancingPolicy())
.build();
session = cluster.connect(keyspace);
}
Create your own policy!
Add a Load Balancing Policy](https://image.slidesharecdn.com/cassandrasummit-datastaxjavadriver-130613113240-phpapp01/85/Cassandra-summit-2013-DataStax-Java-Driver-Unleashed-23-320.jpg)
![contactPoints = {“10.0.0.1”,”10.0.0.2”}
keyspace = “videodb”
public VideoDbBasicImpl(List<String> contactPoints, String keyspace) {
cluster = Cluster
.builder()
.addContactPoints(
! contactPoints.toArray(new String[contactPoints.size()]))
.withLoadBalancingPolicy(Policies.defaultLoadBalancingPolicy())
.withRetryPolicy(Policies.defaultRetryPolicy())
.build();
session = cluster.connect(keyspace);
}
Create your own policy!
Specify a Retry Policy](https://image.slidesharecdn.com/cassandrasummit-datastaxjavadriver-130613113240-phpapp01/85/Cassandra-summit-2013-DataStax-Java-Driver-Unleashed-25-320.jpg)
Cassandra summit 2013 - DataStax Java Driver Unleashed!
- 1. DataStax Java Driver Unleashed!
- 2. CQL The new face of Cassandra * CQL3 * Simpler Data Model using Denormalized Tables * SQL-like Query Language * Schema Definition * CQL Native Protocol * Introduced in Cassandra 1.2 * Designed for CQL3 * Thrift will keep being supported by Cassandra
- 3. * Cassandra lives closer to users and application * Data model expresses your application intent * Not made for generalizable queries * Key to a successful project CQL Data Model Overview
- 4. CQL3 Data Model Data duplicated over several tables CQL3 Query Language comes with a new Data Model abstraction made of denormalized, statically defined tables
- 5. CQL3 Data Model gmason user_id 1735 tweet_id phenry author Give me liberty or give me death body Partition Key gmason 1742 gwashington I chopped down the cherry tree ahamilton 1767 jadams A government of laws, not men ahamilton 1794 gwashington I chopped down the cherry tree Clustering Key Timeline Table
- 6. CQL3 Data Model gmason user_id 1735 tweet_id phenry author Give me liberty or give me death body Partition Key gmason 1742 gwashington I chopped down the cherry tree ahamilton 1767 jadams A government of laws, not men ahamilton 1794 gwashington I chopped down the cherry tree Clustering Key Timeline Table CREATE TABLE timeline ( user_id varchar, tweet_id timeuuid, author varchar, body varchar, PRIMARY KEY (user_id, tweet_id)); CQL
- 7. DB API CQL Native Protocol CQL API OO API Next Generation Driver New Driver Architecture
- 8. * Reference Implementation * Asynchronous architecture based on Netty * Prepared Statements Support * Automatic Fail-over * Node Discovery * Cassandra Tracing Support * Tunable Policies Java Driver Overview
- 9. Client Without Request Pipelining Cassandra Client Cassandra With Request Pipelining Request Pipelining
- 10. Client Without Notifications With Notifications Node Node Node Client Node Node Node Notifications
- 13. contactPoints = {“10.0.0.1”,”10.0.0.2”} keyspace = “videodb” public VideoDbBasicImpl(List<String> contactPoints, String keyspace) { cluster = Cluster .builder() .addContactPoints( ! contactPoints.toArray(new String[contactPoints.size()])) .build(); session = cluster.connect(keyspace); } Creating a Basic Connection
- 14. public void setUserByUsingString(User user) { StringBuffer userInsert = new StringBuffer( "INSERT INTO users (username, firstname, lastname, email, password, created_date) VALUES ("); userInsert.append("'" + user.getUsername() + "'"); userInsert.append("'" + user.getFirstname() + "'"); userInsert.append("'" + user.getLastname() + "'"); userInsert.append("'" + user.getEmail() + "'"); userInsert.append("'" + user.getPassword() + "'"); userInsert.append("'" + user.getCreated_date().toString() + "'"); userInsert.append(")"); session.execute(userInsert.toString()); } Basic write using insert
- 15. ! public User getUserByUsernameUsingString(String username) { ! ! User user = new User(); ! ! ResultSet rs = session.execute("SELECT * FROM users WHERE username = '" ! ! ! ! + username + "'"); ! ! // A result set has Rows which can be iterated over ! ! for (Row row : rs) { ! ! ! user.setUsername(username); ! ! ! user.setFirstname(row.getString("firstname")); ! ! ! user.setLastname(row.getString("lastname")); ! ! ! user.setEmail(row.getString("email")); ! ! ! user.setPassword(row.getString("Password")); ! ! ! user.setCreated_date(row.getDate("created_date")); ! ! } ! ! return user; ! } Basic Read using Select
- 16. public void setUserByPreparedStatement(User user) { BoundStatement bs = setUser.bind(); bs.setString("username", user.getUsername()); bs.setString("firstname", user.getFirstname()); bs.setString("lastname", user.getLastname()); bs.setString("email", user.getEmail()); bs.setString("password", user.getPassword()); bs.setDate("created_date", user.getCreated_date()); ! ! session.execute(bs); } Writing with Prepared Statements
- 17. public List<Video> getVideosByUsernameUsingAsyncRead(String username) { BoundStatement bs = getVideosByUsernamePreparedStatement.bind(); List<ResultSetFuture> futures = new ArrayList<ResultSetFuture>(); List<Video> videos = new ArrayList<Video>(); bs.setString("username", username); for (Row row : session.execute(bs)) { futures.add(session.executeAsync(getVideoByIDPreparedStatement .bind(row.getUUID("videoid")))); } for (ResultSetFuture future : futures) { for (Row row : future.getUninterruptibly()) { Video video = new Video(); video.setVideoid(row.getUUID("videoid")); videos.add(video); } } return videos; } Asynchronous Read
- 18. for (String tag : tags) { BoundStatement bs = getVideosByTagPreparedStatement.bind(tag); final ResultSetFuture future = session.executeAsync(bs); future.addListener(new Runnable() { public void run() { for (Row row : future.getUninterruptibly()) { UUID videoId = row.getUUID("videoid"); if (videoIds.putIfAbsent(videoId, PRESENT) == null) { videoFutures.add(session .executeAsync(getVideoByIDPreparedStatement .bind(videoId))); } } } }, executor); } Performing a Read with a Listener
- 19. public Video getVideoByIdUsingQueryBuilder(String videoId) { Video video = new Video(); Query query = select().all().from("videodb", "videos") .where(eq("videoId", videoId)).limit(10); query.setConsistencyLevel(ConsistencyLevel.ONE); ResultSet rs = session.execute(query); for (Row row : rs) { video.setVideoid(row.getUUID("videoid")); video.setVideoname(row.getString("videoName")); video.setUsername(row.getString("username")); video.setDescription(row.getString("description")); } return video; } Using the Query Builder
- 20. Load Balancing Policy Node Node Node Health Monitor Load Balancing and Failover ReconnectionNotifications Client Retry Policy Response Dispatcher 1 3 2 4 5 6
- 21. Node Node NodeClient Datacenter B Node Node Node Client Client Client Client Client Datacenter A Local nodes are queried first, if non are available, the request will be sent to a remote node. Multi Datacenter Load Balancing
- 22. Multi Datacenter Load Balancing Node Node Replica Node Client Node NodeReplica Replica Nodes that own a Replica of the data being read or written by the query will be contacted first.
- 23. contactPoints = {“10.0.0.1”,”10.0.0.2”} keyspace = “videodb” public VideoDbBasicImpl(List<String> contactPoints, String keyspace) { cluster = Cluster .builder() .addContactPoints( ! contactPoints.toArray(new String[contactPoints.size()])) .withLoadBalancingPolicy(Policies.defaultLoadBalancingPolicy()) .build(); session = cluster.connect(keyspace); } Create your own policy! Add a Load Balancing Policy
- 24. Client If the requested Consistency Level cannot be reached (QUORUM here), a second request with a lower CL is sent automatically. Node Node Replica Replica Node Replica Downgrading Retry Policy
- 25. contactPoints = {“10.0.0.1”,”10.0.0.2”} keyspace = “videodb” public VideoDbBasicImpl(List<String> contactPoints, String keyspace) { cluster = Cluster .builder() .addContactPoints( ! contactPoints.toArray(new String[contactPoints.size()])) .withLoadBalancingPolicy(Policies.defaultLoadBalancingPolicy()) .withRetryPolicy(Policies.defaultRetryPolicy()) .build(); session = cluster.connect(keyspace); } Create your own policy! Specify a Retry Policy
- 26. public enum Gender { @EnumValue("m") MALE, @EnumValue("f") FEMALE; } @Table(name = "user") public class User { @PartitionKey @Column(name = "user_id") private String userId; private String name; private String email; private Gender gender; } Object Mapping
- 27. DevCenter an IDE for Developers
- 28. Questions ?