How to set query timeout in Sequelize?

In Sequelize, configuring query timeout is a crucial feature, especially when working with large databases or applications that require a seamless user experience. Below are the steps to set query timeout in Sequelize:

Step 1: Update Sequelize Configuration

First, ensure that the query timeout option is configured during Sequelize initialization. Sequelize leverages the connection settings of the underlying database library (e.g., PostgreSQL, MySQL) to set the timeout, which is typically defined in the Sequelize configuration file.

For example, for PostgreSQL, you can use options.dialectOptions in the Sequelize configuration to specify timeout settings:

javascript
const sequelize = new Sequelize('database', 'username', 'password', {
  host: 'host',
  dialect: 'postgres',
  dialectOptions: {
    statement_timeout: 5000,  // 5000 milliseconds, i.e., 5 seconds
    query_timeout: 5000
  }
});

Step 2: Set Timeout for Specific Queries

If you need to set a timeout for specific queries rather than globally, Sequelize supports configuring it at the query level. You can achieve this by passing the options parameter when invoking query methods:

javascript
try {
  const users = await sequelize.query("SELECT * FROM `users`", {
    type: sequelize.QueryTypes.SELECT,
    timeout: 3000  // 3000 milliseconds, i.e., 3 seconds
  });
} catch (error) {
  console.error('Query timeout: ', error);
}

In this example, if the query execution exceeds 3 seconds, it will throw a timeout error.

Step 3: Error Handling

After setting the timeout, it is essential to handle potential timeout errors correctly. Applications using timeout settings should always be prepared to catch and manage these errors appropriately:

javascript
try {
  const result = await sequelize.query("SELECT * FROM `users`", { timeout: 3000 });
} catch (error) {
  if (error instanceof sequelize.TimeoutError) {
    // Handle timeout error
    console.log('Query was canceled due to timeout');
  } else {
    // Handle other errors
    console.error('Query failed: ', error);
  }
}

Summary

By following these steps, you can effectively configure and manage query timeout in Sequelize, which is vital for maintaining database performance and user experience. Properly setting and handling query timeout ensures your application remains robust and user-friendly when encountering database query delays.