YugabyteDB JDBC smart driver is a distributed JDBC driver for YSQL built on the PostgreSQL JDBC driver, with additional connection load balancing features:

  • It is cluster-aware, which eliminates the need for an external load balancer.
  • It is topology-aware, which is essential for geographically-distributed applications.

Load balancing

The YugabyteDB JDBC smart driver has the following load balancing features:

  • Uniform load balancing

    In this mode, the driver makes the best effort to uniformly distribute the connections to each YugabyteDB server. For example, if a client application creates 100 connections to a YugabyteDB cluster consisting of 10 servers, then the driver creates 10 connections to each server. If the number of connections are not exactly divisible by the number of servers, then a few may have 1 less or 1 more connection than the others. This is the client view of the load, so the servers may not be well balanced if other client applications are not using the YugabyteDB JDBC driver.

    The driver package includes a YBClusterAwareDataSource class that uses one initial contact point for the YugabyteDB cluster as a means of discovering all the nodes and, if required, refreshing the list of live endpoints with every new connection attempt. The refresh is triggered if stale information (older than 5 minutes) is discovered.

  • Topology-aware load balancing

    Because YugabyteDB clusters can have servers in different regions and availability zones, the YugabyteDB JDBC driver is topology-aware. The driver uses servers that are part of a set of geo-locations specified by topology keys. This means it can be configured to create connections only on servers that are in specific regions and zones. This is beneficial for client applications that need to connect to the geographically nearest regions and availability zone for lower latency; the driver tries to uniformly load only those servers that belong to the specified regions and zone.

The YugabyteDB JDBC driver can be configured with popular pooling solutions such as Hikari and Tomcat. Different pools can be configured with different load balancing policies if required. For example, an application can configure one pool with topology awareness for one region and its availability zones, and configure another pool to talk to a completely different region.

Quick start

Learn how to establish a connection to a YugabyteDB database and begin basic CRUD operations using the steps in Build an Application.

Download the driver dependency

YugabyteDB JDBC Driver is available as maven dependency. Download the driver by adding the following dependency entries in the java project.

Maven dependency

To get the driver and HikariPool from Maven, add the following dependencies to the Maven project:

<dependency>
  <groupId>com.yugabyte</groupId>
  <artifactId>jdbc-yugabytedb</artifactId>
  <version>42.3.0</version>
</dependency>

<!-- https://mvnrepository.com/artifact/com.zaxxer/HikariCP -->
<dependency>
  <groupId>com.zaxxer</groupId>
  <artifactId>HikariCP</artifactId>
  <version>4.0.3</version>
</dependency>

Gradle dependency

To get the driver and HikariPool, add the following dependencies to the Gradle project:

// https://mvnrepository.com/artifact/org.postgresql/postgresql
implementation 'com.yugabyte:jdbc-yugabytedb:42.3.0'
implementation 'com.zaxxer:HikariCP:4.0.3'

Fundamentals

Learn how to perform the common tasks required for Java App Development using the PostgreSQL JDBC driver

Note

The driver requires YugabyteDB version 2.7.2.0 or higher, and Java 8 or above.

Load balancing connection properties

The following connection properties need to be added to enable load balancing:

  • load-balance - enable cluster-aware load balancing by setting this property to true; disabled by default.
  • topology-keys - provide comma-separated geo-location values to enable topology-aware load balancing. Geo-locations can be provided as cloud.region.zone.

Use the driver

The YugabyteDB JDBC driver's driver class is com.yugabyte.Driver.

To use the driver, do the following:

  • Pass new connection properties for load balancing in the connection URL or properties pool.

    To enable uniform load balancing across all servers, you set the load-balance property to true in the URL, as per the following example:

    String yburl = "jdbc:yugabytedb://127.0.0.1:5433/yugabyte?user=yugabyte&password=yugabyte&load-balance=true";
    DriverManager.getConnection(yburl);
    

    To specify topology keys, you set the topology-keys property to comma separated values, as per the following example:

    String yburl = "jdbc:yugabytedb://127.0.0.1:5433/yugabyte?user=yugabyte&password=yugabyte&load-balance=true&topology-keys=cloud1.region1.zone1,cloud1.region1.zone2";
    DriverManager.getConnection(yburl);
    
  • Configure YBClusterAwareDataSource for uniform load balancing and then use it to create a connection, as per the following example:

    String jdbcUrl = "jdbc:yugabytedb://127.0.0.1:5433/yugabyte";
    YBClusterAwareDataSource ds = new YBClusterAwareDataSource();
    ds.setUrl(jdbcUrl);
    // Set topology keys to enable topology-aware distribution
    ds.setTopologyKeys("cloud1.region1.zone1,cloud1.region2.zone2");
    // Provide more end points to prevent first connection failure
    // if an initial contact point is not available
    ds.setAdditionalEndpoints("127.0.0.2:5433,127.0.0.3:5433");
    
    Connection conn = ds.getConnection();
    
  • Configure YBClusterAwareDataSource with a pooling solution such as Hikari and then use it to create a connection, as per the following example:

    Properties poolProperties = new Properties();
    poolProperties.setProperty("dataSourceClassName", "com.yugabyte.ysql.YBClusterAwareDataSource");
    poolProperties.setProperty("maximumPoolSize", 10);
    poolProperties.setProperty("dataSource.serverName", "127.0.0.1");
    poolProperties.setProperty("dataSource.portNumber", "5433");
    poolProperties.setProperty("dataSource.databaseName", "yugabyte");
    poolProperties.setProperty("dataSource.user", "yugabyte");
    poolProperties.setProperty("dataSource.password", "yugabyte");
    // If you want to provide additional end points
    String additionalEndpoints = "127.0.0.2:5433,127.0.0.3:5433,127.0.0.4:5433,127.0.0.5:5433";
    poolProperties.setProperty("dataSource.additionalEndpoints", additionalEndpoints);
    // If you want to load balance between specific geo locations using topology keys
    String geoLocations = "cloud1.region1.zone1,cloud1.region2.zone2";
    poolProperties.setProperty("dataSource.topologyKeys", geoLocations);
    
    poolProperties.setProperty("poolName", name);
    
    HikariConfig config = new HikariConfig(poolProperties);
    config.validate();
    HikariDataSource ds = new HikariDataSource(config);
    
    Connection conn = ds.getConnection();
    

Try it out

This tutorial shows how to use the YugabyteDB JDBC Driver with YugabyteDB. It starts by creating a three-node cluster with a replication factor of 3. This tutorial uses the yb-ctl utility.

Next, you use yb-sample-apps to demonstrate the driver's load balancing features and create a Maven project to learn how to use the driver in an application.

Note

The driver requires YugabyteDB version 2.7.2.0 or higher, and Java 8 or above.

Install YugabyteDB and create a local cluster

Create a universe with a 3-node RF-3 cluster with some fictitious geo-locations assigned. The placement values used are just tokens and have nothing to do with actual AWS cloud regions and zones.

$ cd <path-to-yugabytedb-installation>

./bin/yb-ctl create --rf 3 --placement_info "aws.us-west.us-west-2a,aws.us-west.us-west-2a,aws.us-west.us-west-2b"

Check uniform load balancing using yb-sample-apps

  • Download the yb-sample-apps JAR file.

    wget https://github.com/yugabyte/yb-sample-apps/releases/download/v1.4.0/yb-sample-apps.jar
    
  • Run the SqlInserts workload application, which creates multiple threads that perform read and write operations on a sample table created by the app. Uniform load balancing is enabled by default in all Sql* workloads of the yb-sample-apps, including SqlInserts.

    java -jar yb-sample-apps.jar  \
         --workload SqlInserts \
         --num_threads_read 15 --num_threads_write 15 \
         --nodes 127.0.0.1:5433,127.0.0.2:5433,127.0.0.3:5433
    

The application creates 30 connections, 1 for each reader and writer threads. To verify the behavior, wait for the app to create connections and then visit http://<host>:13000/rpcz from your browser for each node to see that the connections are equally distributed among the nodes. This URL presents a list of connections where each element of the list has some information about the connection as shown in the following screenshot. You can count the number of connections from that list, or search for the occurrence count of the host keyword on that webpage. Each node should have 10 connections.

Load balancing with host connections

Check topology-aware load balancing using yb-sample-apps

For topology-aware load balancing, run the SqlInserts workload application with the topology-keys1 property set to aws.us-west.us-west-2a; only two nodes will be used in this case.

java -jar yb-sample-apps.jar \
      --workload SqlInserts \
      --nodes 127.0.0.1:5433,127.0.0.2:5433,127.0.0.3:5433 \
      --num_threads_read 15 --num_threads_write 15 \
      --topology_keys aws.us-west.us-west-2a

To verify the behavior, wait for the app to create connections and then navigate to http://<host>:13000/rpcz. The first two nodes should have 15 connections each, and the third node should have zero connections.

Clean up

When you're done experimenting, run the following command to destroy the local cluster:

./bin/yb-ctl destroy

Other examples

To access sample applications that use the YugabyteDB JDBC driver, visit YugabyteDB JDBC driver.

To use the samples, complete the following steps:

  • Install YugabyteDB by following the instructions in Quick start.

  • Build the examples by running mvn package.

  • Run the run.sh script, as per the following guideline:

    ./run.sh [-v] [-i] -D -<path_to_yugabyte_installation>
    

    In the preceding command, replace:

    • [-v] [-i] with -v if you want to run the script in VERBOSE mode.

    • [-v] [-i] with -i if you want to run the script in INTERACTIVE mode.

    • [-v] [-i] with -v -i if you want to run the script in both VERBOSE and INTERACTIVE mode at the same time.

    • <path_to_yugabyte_installation> with the path to the directory where you installed YugabyteDB.

    The following is an example of a shell command that runs the script:

    ./run.sh -v -i -D ~/yugabyte-2.7.2.0/
    

    Note

    The driver requires YugabyteDB version 2.7.2.0 or higher.

    The run script starts a YugabyteDB cluster, demonstrates load balancing through Java applications, and then destroys the cluster.

    When started, the script displays a menu with two options: UniformLoadBalance and TopologyAwareLoadBalance. Choose one of these options to run the corresponding script with its Java application in the background.

Learn more

To learn more about the driver, you can read the architecture documentation.