Usage notes

Run a query job in the Ad-Hoc Query module. If the returned results contain the following information, the MCQA feature is enabled. For more information about the ad hoc query feature, see Create an ad hoc query.

Run a query job in the Manually Triggered Workflow module. If the returned results contain the following information, the MCQA feature is enabled. For more information about the Manually Triggered Workflow feature, see Manage manually triggered workflows.

You can use the MaxCompute JDBC driver in the following situations:

• Use the MaxCompute JDBC driver to connect to MaxCompute. For more information, see Usage notes of JDBC. To enable the MCQA feature, you must modify the relevant configuration. For more information, see Enable MCQA on MaxCompute JDBC.
• Use the MaxCompute JDBC driver to connect to Tableau. Then, you can use Tableau to analyze MaxCompute data in a visualized manner. For more information, see Configure MaxCompute JDBC on Tableau. To enable the MCQA feature in this scenario, you must modify the relevant configuration. For more information, see Enable MCQA on Tableau based on MaxCompute JDBC.
• Use the MaxCompute JDBC driver to connect to SQL Workbench/J. Then, you can use SQL Workbench/J to execute SQL statements on MaxCompute data. For more information, see Configure MaxCompute JDBC on SQL Workbench/J. To enable the MCQA feature in this scenario, you must modify the relevant configuration. For more information, see Enable MCQA on SQL Workbench/J based on MaxCompute JDBC.

The following example shows how to configure a server:

http://service.cn-beijing.maxcompute.aliyun.com/api?project=****_beijing&interactiveMode=true&enableOdpsLogger=true

To perform operations on specific tables in a MaxCompute project, add the table_list=table_name1, table_name2 property in the parameters of the server. Separate table names with commas (,). An excessive number of tables may cause Tableau to open slowly. We recommend that you use this method to load only the required tables. The following example shows how to load specified tables in Tableau:

http://service.cn-beijing.maxcompute.aliyun.com/api?project=****_beijing&interactiveMode=true&enableOdpsLogger=true&table_list=orders,customers

For tables that includes a large number of partitions, we recommend that you do not use data from all partitions as the data source. You can filter the required partitions or run custom SQL queries to obtain the required data.

Specify the URL in the following format: jdbc:odps:<MaxCompute_endpoint>? project=<MaxCompute_project_name>&accessId=<AccessKey ID>&accessKey=<AccessKey Secret>&charset=UTF-8&interactiveMode=true. Parameter description:

• maxcompute_endpoint: the endpoint of the region where your MaxCompute service is deployed. For more information, see Configure endpoints.
• maxcompute_project_name: the name of your MaxCompute project.
• AccessKey ID: the AccessKey ID that has the permissions to access the specified project.
• AccessKey Secret: the AccessKey secret that corresponds to the AccessKey ID.
• charset=UTF-8: the character set encoding format.
• interactiveMode: specifies whether to enable the MCQA feature. To enable the MCQA feature, set this parameter to true.

For more information about Alibaba Cloud MaxCompute SDK for Java, see Overview. You must configure the POM dependency by using Maven. The following sample code demonstrates how to configure the POM dependency:

<dependency>
  <groupId>com.aliyun.odps</groupId>
  <artifactId>odps-sdk-core</artifactId>
  <version>0.35.5-public</version>
</dependency>

The following sample code demonstrates how to create a Java program:

import com.aliyun.odps.Odps;
import com.aliyun.odps.OdpsException;
import com.aliyun.odps.OdpsType;
import com.aliyun.odps.account.Account;
import com.aliyun.odps.account.AliyunAccount;
import com.aliyun.odps.data.Record;
import com.aliyun.odps.data.ResultSet;
import com.aliyun.odps.sqa.*;

import java.io.IOException;
import java.util.*;

public class SQLExecutorExample {

    public static void SimpleExample() {
        // Specify the account and project information.
        Account account = new AliyunAccount("your_access_id", "your_access_key");
        Odps odps = new Odps(account);
        odps.setDefaultProject("your_project_name");
        odps.setEndpoint("http://service.<regionid>.maxcompute.aliyun.com/api");

        // Prepare to create SQL executors.
        SQLExecutorBuilder builder = SQLExecutorBuilder.builder();

        SQLExecutor sqlExecutor = null;
        try {
            // run in offline mode or run in interactive mode
            if (false) {
                // Create an executor that runs offline SQL queries by default.
                sqlExecutor = builder.odps(odps).executeMode(ExecuteMode.OFFLINE).build();
            } else {
                // Create an executor that runs MCQA SQL queries by default.
                sqlExecutor = builder.odps(odps).executeMode(ExecuteMode.INTERACTIVE).build();
            }
            // Pass special query settings if required.
            Map<String, String> queryHint = new HashMap<>();
            queryHint.put("odps.sql.mapper.split.size", "128");
            // Submit a query job. You can pass hints.
            sqlExecutor.run("select count(1) from test_table;", queryHint);

            // List some supported API operations that are used to query information.
            // UUID
            System.out.println("ExecutorId:" + sqlExecutor.getId());
            // Query the Logview of the current query job.
            System.out.println("Logview:" + sqlExecutor.getLogView());
            // Query the instance on which the current query job is run. In interactive mode, multiple query jobs may be run on the same instance.
            System.out.println("InstanceId:" + sqlExecutor.getInstance().getId());
            // Query the progress of the current query job. You can check the progress bar in the console.
            System.out.println("QueryStageProgress:" + sqlExecutor.getProgress());
            // Query the change logs about the execution status for the current query job, such as rollback messages.
            System.out.println("QueryExecutionLog:" + sqlExecutor.getExecutionLog());

            // Provide two API operations to query results.
            if(false) {
                // Query the results of all query jobs. This is a synchronous operation and may occupy this thread until the query succeeds or fails.
                List<Record> records = sqlExecutor.getResult();
                printRecords(records);
            } else {
                // Query the ResultSet iterator of the query results. This is a synchronous operation and may occupy this thread until the query succeeds or fails.
                ResultSet resultSet = sqlExecutor.getResultSet();
                while (resultSet.hasNext()) {
                    printRecord(resultSet.next());
                }
            }

            // run another query
            sqlExecutor.run("select * from test_table;", new HashMap<>());
            if(false) {
                // Query all query results. This is a synchronous operation and may occupy this thread until the query succeeds or fails.
                List<Record> records = sqlExecutor.getResult();
                printRecords(records);
            } else {
                // Query the ResultSet iterator of the query results. This is a synchronous operation and may occupy this thread until the query succeeds or fails.
                ResultSet resultSet = sqlExecutor.getResultSet();
                while (resultSet.hasNext()) {
                    printRecord(resultSet.next());
                }
            }
        } catch (OdpsException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (sqlExecutor ! = null) {
                // Close the executor and release related resources.
                sqlExecutor.close();
            }
        }
    }

    // SQLExecutor can be reused by pool mode
    public static void ExampleWithPool() {
        // Specify the account and project information.
        Account account = new AliyunAccount("your_access_id", "your_access_key");
        Odps odps = new Odps(account);
        odps.setDefaultProject("your_project_name");
        odps.setEndpoint("http://service.<regionid>.maxcompute.aliyun.com/api");

        // Run queries by using a connection pool.
        SQLExecutorPool sqlExecutorPool = null;
        SQLExecutor sqlExecutor = null;
        try {
            // Prepare a connection pool. Specify the connection pool size and the default execution mode.
            SQLExecutorPoolBuilder builder = SQLExecutorPoolBuilder.builder();
            builder.odps(odps)
                    .initPoolSize(1) // init pool executor number
                    .maxPoolSize(5)  // max executors in pool
                    .executeMode(ExecuteMode.INTERACTIVE); // run in interactive mode

            sqlExecutorPool = builder.build();
            // Obtain an executor from the connection pool. If no executor can be obtained from the connection pool, you can add an executor. Make sure that the total number of executors does not exceed the upper limit.
            sqlExecutor = sqlExecutorPool.getExecutor();

            // Use the executor in the same way it is used in the preceding example.
            sqlExecutor.run("select count(1) from test_table;", new HashMap<>());
            System.out.println("InstanceId:" + sqlExecutor.getId());
            System.out.println("Logview:" + sqlExecutor.getLogView());

            List<Record> records = sqlExecutor.getResult();
            printRecords(records);
        } catch (OdpsException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            sqlExecutor.close();
        }
        sqlExecutorPool.close();
    }

    private static void printRecord(Record record) {
        for (int k = 0; k < record.getColumnCount(); k++) {

            if (k ! = 0) {
                System.out.print("\t");
            }

            if (record.getColumns()[k].getType().equals(OdpsType.STRING)) {
                System.out.print(record.getString(k));
            } else if (record.getColumns()[k].getType().equals(OdpsType.BIGINT)) {
                System.out.print(record.getBigint(k));
            } else {
                System.out.print(record.get(k));
            }
        }
    }

    private static void printRecords(List<Record> records) {
        for (Record record : records) {
            printRecord(record);
            System.out.println();
        }
    }

    public static void main(String args[]) {
        SimpleExample();
        ExampleWithPool();
    }
}