Function createAndExecuteQueryPartitions

spanner/batch.js:17–76

(
  instanceId,
  databaseId,
  projectId
)

'use strict';

async function createAndExecuteQueryPartitions(
  instanceId,
  databaseId,
  projectId
) {
  // [START spanner_batch_client]
  // Imports the Google Cloud client library
  const {Spanner} = require('@google-cloud/spanner');

  /**
   * TODO(developer): Uncomment the following lines before running the sample.
   */
  // const projectId = 'my-project-id';
  // const instanceId = 'my-instance';
  // const databaseId = 'my-database';

  // Creates a client
  const spanner = new Spanner({
    projectId: projectId,
  });

  // Gets a reference to a Cloud Spanner instance and database
  const instance = spanner.instance(instanceId);
  const database = instance.database(databaseId);

  let transaction;

  try {
    [transaction] = await database.createBatchTransaction();

    const query = {
      sql: 'SELECT * FROM Singers',
      // DataBoost option is an optional parameter which can also be used for partition read
      // and query to execute the request via spanner independent compute resources.
      dataBoostEnabled: true,
    };

    // A Partition object is serializable and can be used from a different process.
    const [partitions] = await transaction.createQueryPartitions(query);
    console.log(`Successfully created ${partitions.length} query partitions.`);

    let rowCount = 0;
    const promises = partitions.map(partition =>
      transaction.execute(partition).then(results => {
        const rows = results[0].map(row => row.toJSON());
        rowCount += rows.length;
      })
    );
    await Promise.all(promises);
    console.log(`Successfully received ${rowCount} from executed partitions.`);
  } catch (err) {
    console.error('Error executing query partitions:', err);
  } finally {
    if (transaction) {
      transaction.close();
    }
    await database.close();
  }