JDBC set statement for query options

Use the SET statement to specify query options by using JDBC.

Explore further

For detailed documentation that includes this code sample, see the following:

• Manage the query optimizer

Code sample

Java

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

class SetQueryOptionsExample {

  static void setQueryOptions() throws SQLException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";
    setQueryOptions(projectId, instanceId, databaseId);
  }

  static void setQueryOptions(String projectId, String instanceId, String databaseId)
      throws SQLException {
    String connectionUrl =
        String.format(
            "jdbc:cloudspanner:/projects/%s/instances/%s/databases/%s",
            projectId, instanceId, databaseId);
    try (Connection connection = DriverManager.getConnection(connectionUrl);
        Statement statement = connection.createStatement()) {
      // Instruct the JDBC connection to use version '1' of the query optimizer.
      // NOTE: Use `SET SPANNER.OPTIMIZER_VERSION='1`` when connected to a PostgreSQL database.
      statement.execute("SET OPTIMIZER_VERSION='1'");
      // Execute a query using the latest optimizer version.
      try (ResultSet rs =
          statement.executeQuery(
              "SELECT SingerId, FirstName, LastName FROM Singers ORDER BY LastName")) {
        while (rs.next()) {
          System.out.printf("%d %s %s%n", rs.getLong(1), rs.getString(2), rs.getString(3));
        }
      }
      // NOTE: Use `SHOW SPANNER.OPTIMIZER_VERSION` when connected to a PostgreSQL database.
      try (ResultSet rs = statement.executeQuery("SHOW VARIABLE OPTIMIZER_VERSION")) {
        while (rs.next()) {
          System.out.printf("Optimizer version: %s%n", rs.getString(1));
        }
      }
    }
  }
}

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