createPoolCluster

info

For queries please see the Simple Queries and Prepared Statements examples.

add(group, connectionUri)

add(group: string, connectionUri: string)

promise.js

import mysql from 'mysql2/promise';

try {
  const poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', 'mysql://root:password@localhost:3306/test');
  // poolCluster.add('clusterB', '...');

  const connection = await poolCluster.getConnection('clusterA');
  // ... some query

  connection.release();

  // Close the pool cluster
  await poolCluster.end();
} catch (err) {
  console.log(err);
}

warning

Don't forget to release the connection when finished by using:

• connection.release()

callback.js

const mysql = require('mysql2');

const poolCluster = mysql.createPoolCluster();

poolCluster.add('clusterA', 'mysql://root:password@localhost:3306/test');
// poolCluster.add('clusterB', '...');

poolCluster.getConnection('clusterA', function (err, connection) {
  if (err instanceof Error) {
    console.log(err);
    return;
  }

  // ... some query

  connection.release();

  // Close the pool cluster
  poolCluster.end();
});

warning

Don't forget to release the connection when finished by using:

• connection.release()

await using

import mysql from 'mysql2/promise';

{
  // .end() is called automatically when leaving the scope
  await using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', 'mysql://root:password@localhost:3306/test');
  // poolCluster.add('clusterB', '...');

  // .release() is called automatically when leaving the scope
  await using connection = await poolCluster.getConnection('clusterA');

  // ... some query
}

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

using

const mysql = require('mysql2');

{
  // .end() is called automatically when leaving the scope
  using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', 'mysql://root:password@localhost:3306/test');
  // poolCluster.add('clusterB', '...');

  poolCluster.getConnection('clusterA', function (err, _connection) {
    if (err instanceof Error) {
      console.log(err);
      return;
    }

    // .release() is called automatically when leaving the scope
    using connection = _connection;

    // ... some query
  });
}

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

---

add(group, config)

add(group: string, config: PoolOptions)

promise.js

import mysql from 'mysql2/promise';

try {
  const poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    host: 'localhost',
    user: 'root',
    database: 'test',
    // port: 3306,
    // password: '',
  });
  // poolCluster.add('clusterB', '...');

  const connection = await poolCluster.getConnection('clusterA');
  // ... some query

  connection.release();

  // Close the pool cluster
  await poolCluster.end();
} catch (err) {
  console.log(err);
}

warning

Don't forget to release the connection when finished by using:

• connection.release()

callback.js

const mysql = require('mysql2');

const poolCluster = mysql.createPoolCluster();

poolCluster.add('clusterA', {
  host: 'localhost',
  user: 'root',
  database: 'test',
  // port: 3306,
  // password: '',
});
// poolCluster.add('clusterB', '...');

poolCluster.getConnection('clusterA', function (err, connection) {
  if (err instanceof Error) {
    console.log(err);
    return;
  }

  // ... some query

  connection.release();

  // Close the pool cluster
  poolCluster.end();
});

warning

Don't forget to release the connection when finished by using:

• connection.release()

await using

import mysql from 'mysql2/promise';

{
  // .end() is called automatically when leaving the scope
  await using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    host: 'localhost',
    user: 'root',
    database: 'test',
    // port: 3306,
    // password: '',
  });
  // poolCluster.add('clusterB', '...');

  // .release() is called automatically when leaving the scope
  await using connection = await poolCluster.getConnection('clusterA');

  // ... some query
}

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

using

const mysql = require('mysql2');

{
  // .end() is called automatically when leaving the scope
  using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    host: 'localhost',
    user: 'root',
    database: 'test',
    // port: 3306,
    // password: '',
  });
  // poolCluster.add('clusterB', '...');

  poolCluster.getConnection('clusterA', function (err, _connection) {
    if (err instanceof Error) {
      console.log(err);
      return;
    }

    // .release() is called automatically when leaving the scope
    using connection = _connection;

    // ... some query
  });
}

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

---

add(group, config) — SHA1

add(group: string, config: PoolOptions)

promise.js

import mysql from 'mysql2/promise';

try {
  const poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    passwordSha1: Buffer.from(
      '8bb6118f8fd6935ad0876a3be34a717d32708ffd',
      'hex'
    ),
  });
  // poolCluster.add('clusterB', '...');

  const connection = await poolCluster.getConnection('clusterA');
  // ... some query

  connection.release();

  // Close the pool cluster
  await poolCluster.end();
} catch (err) {
  console.log(err);
}

warning

Don't forget to release the connection when finished by using:

• connection.release()

callback.js

const mysql = require('mysql2');

const poolCluster = mysql.createPoolCluster();

poolCluster.add('clusterA', {
  // ...
  passwordSha1: Buffer.from('8bb6118f8fd6935ad0876a3be34a717d32708ffd', 'hex'),
});
// poolCluster.add('clusterB', '...');

poolCluster.getConnection('clusterA', function (err, connection) {
  if (err instanceof Error) {
    console.log(err);
    return;
  }

  // ... some query

  connection.release();

  // Close the pool cluster
  poolCluster.end();
});

warning

Don't forget to release the connection when finished by using:

• connection.release()

await using

import mysql from 'mysql2/promise';

{
  // .end() is called automatically when leaving the scope
  await using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    passwordSha1: Buffer.from(
      '8bb6118f8fd6935ad0876a3be34a717d32708ffd',
      'hex'
    ),
  });
  // poolCluster.add('clusterB', '...');

  // .release() is called automatically when leaving the scope
  await using connection = await poolCluster.getConnection('clusterA');

  // ... some query
}

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

using

const mysql = require('mysql2');

{
  // .end() is called automatically when leaving the scope
  using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    passwordSha1: Buffer.from(
      '8bb6118f8fd6935ad0876a3be34a717d32708ffd',
      'hex'
    ),
  });
  // poolCluster.add('clusterB', '...');

  poolCluster.getConnection('clusterA', function (err, _connection) {
    if (err instanceof Error) {
      console.log(err);
      return;
    }

    // .release() is called automatically when leaving the scope
    using connection = _connection;

    // ... some query
  });
}

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

---

add(group, config) — SSL

add(group: string, config: PoolOptions)

promise.js

import mysql from 'mysql2/promise';

try {
  const poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    ssl: {
      // key: fs.readFileSync('./certs/client-key.pem'),
      // cert: fs.readFileSync('./certs/client-cert.pem')
      ca: fs.readFileSync('./certs/ca-cert.pem'),
    },
  });
  // poolCluster.add('clusterB', '...');

  const connection = await poolCluster.getConnection('clusterA');
  // ... some query

  connection.release();

  // Close the pool cluster
  await poolCluster.end();
} catch (err) {
  console.log(err);
}

warning

Don't forget to release the connection when finished by using:

• connection.release()

callback.js

const mysql = require('mysql2');

const poolCluster = mysql.createPoolCluster();

poolCluster.add('clusterA', {
  // ...
  ssl: {
    // key: fs.readFileSync('./certs/client-key.pem'),
    // cert: fs.readFileSync('./certs/client-cert.pem')
    ca: fs.readFileSync('./certs/ca-cert.pem'),
  },
});
// poolCluster.add('clusterB', '...');

poolCluster.getConnection('clusterA', function (err, connection) {
  if (err instanceof Error) {
    console.log(err);
    return;
  }

  // ... some query

  connection.release();

  // Close the pool cluster
  poolCluster.end();
});

warning

Don't forget to release the connection when finished by using:

• connection.release()

await using

import mysql from 'mysql2/promise';

{
  // .end() is called automatically when leaving the scope
  await using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    ssl: {
      // key: fs.readFileSync('./certs/client-key.pem'),
      // cert: fs.readFileSync('./certs/client-cert.pem')
      ca: fs.readFileSync('./certs/ca-cert.pem'),
    },
  });
  // poolCluster.add('clusterB', '...');

  // .release() is called automatically when leaving the scope
  await using connection = await poolCluster.getConnection('clusterA');

  // ... some query
}

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

using

const mysql = require('mysql2');

{
  // .end() is called automatically when leaving the scope
  using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    ssl: {
      // key: fs.readFileSync('./certs/client-key.pem'),
      // cert: fs.readFileSync('./certs/client-cert.pem')
      ca: fs.readFileSync('./certs/ca-cert.pem'),
    },
  });
  // poolCluster.add('clusterB', '...');

  poolCluster.getConnection('clusterA', function (err, _connection) {
    if (err instanceof Error) {
      console.log(err);
      return;
    }

    // .release() is called automatically when leaving the scope
    using connection = _connection;

    // ... some query
  });
}

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

certs/ca-cert.pem

• See ssl/certs.

---

add(group, config) — RDS SSL

add(group: string, config: PoolOptions)

You can use Amazon RDS string as value to ssl property to connect to Amazon RDS MySQL over SSL.

In that case https://s3.amazonaws.com/rds-downloads/mysql-ssl-ca-cert.pem CA cert is used:

npm install --save aws-ssl-profiles

promise.js

import mysql from 'mysql2/promise';
import awsCaBundle from 'aws-ssl-profiles';

try {
  const poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    host: 'db.id.ap-southeast-2.rds.amazonaws.com',
    ssl: awsCaBundle,
  });
  // poolCluster.add('clusterB', '...');

  const connection = await poolCluster.getConnection('clusterA');
  // ... some query

  connection.release();

  // Close the pool cluster
  await poolCluster.end();
} catch (err) {
  console.log(err);
}

warning

Don't forget to release the connection when finished by using:

• connection.release()

info

For detailed instructions, please follow the AWS SSL Profiles documentation.

Testing

try {
  const [res] = await connection.query('SHOW `status` LIKE "Ssl_cipher"');
  await poolCluster.end();

  console.log(res);
} catch (err) {
  console.log(err);
}

callback.js

const mysql = require('mysql2');
const awsCaBundle = require('aws-ssl-profiles');

const poolCluster = mysql.createPoolCluster();

poolCluster.add('clusterA', {
  // ...
  host: 'db.id.ap-southeast-2.rds.amazonaws.com',
  ssl: awsCaBundle,
});
// poolCluster.add('clusterB', '...');

poolCluster.getConnection('clusterA', function (err, connection) {
  if (err instanceof Error) {
    console.log(err);
    return;
  }

  // ... some query

  connection.release();

  // Close the pool cluster
  poolCluster.end();
});

warning

Don't forget to release the connection when finished by using:

• connection.release()

info

For detailed instructions, please follow the AWS SSL Profiles documentation.

Testing

connectionquery('SHOW `status` LIKE "Ssl_cipher"', function (err, res) {
  poolCluster.end();

  if (err instanceof Error) {
    console.log(err);
    return;
  }

  console.log(res);
});

await using

import mysql from 'mysql2/promise';
import awsCaBundle from 'aws-ssl-profiles';

{
  // .end() is called automatically when leaving the scope
  await using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    host: 'db.id.ap-southeast-2.rds.amazonaws.com',
    ssl: awsCaBundle,
  });
  // poolCluster.add('clusterB', '...');

  // .release() is called automatically when leaving the scope
  await using connection = await poolCluster.getConnection('clusterA');

  // ... some query
}

info

For detailed instructions, please follow the AWS SSL Profiles documentation.

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

using

const mysql = require('mysql2');
const awsCaBundle = require('aws-ssl-profiles');

{
  // .end() is called automatically when leaving the scope
  using poolCluster = mysql.createPoolCluster();

  poolCluster.add('clusterA', {
    // ...
    host: 'db.id.ap-southeast-2.rds.amazonaws.com',
    ssl: awsCaBundle,
  });
  // poolCluster.add('clusterB', '...');

  poolCluster.getConnection('clusterA', function (err, _connection) {
    if (err instanceof Error) {
      console.log(err);
      return;
    }

    // .release() is called automatically when leaving the scope
    using connection = _connection;

    // ... some query
  });
}

info

For detailed instructions, please follow the AWS SSL Profiles documentation.

tip

await using and using leverage Explicit Resource Management to automatically call .end() or .release() when the variable goes out of scope, so you never forget to clean up connections.

---

add(group, config) — Socks

add(group: string, config: PoolOptions)

A.js

const mysql = require('mysql2');
const SocksConnection = require('socksjs');

const socksProxy = new SocksConnection({ port: 3306 });
const poolCluster = mysql.createPoolCluster();

poolCluster.add('clusterA', {
  stream: socksProxy,
});
// poolCluster.add('clusterB', '...');

const poolNamespace = poolCluster.of('clusterA');

// Close the pool cluster
poolCluster.end();

B.js

const mysql = require('mysql2');
const SocksConnection = require('socksjs');

const poolCluster = mysql.createPoolCluster();

poolCluster.add('clusterA', {
  debug: 1,
  stream: function () {
    return new SocksConnection({ port: 3306 });
  },
});
// poolCluster.add('clusterB', '...');

const poolNamespace = poolCluster.of('clusterA');

// Close the pool cluster
poolCluster.end();

Testing

poolNamespace.execute('SELECT SLEEP(1.1) AS `www`', (err, rows, fields) => {
  if (err instanceof Error) {
    console.log(err);
    return;
  }

  console.log(rows, fields);
});

poolNamespace.execute('SELECT SLEEP(1) AS `qqq`', (err, rows, fields) => {
  if (err instanceof Error) {
    console.log(err);
    return;
  }

  console.log(rows, fields);
});

poolNamespace.execute('SELECT SLEEP(1) AS `qqq`', (err, rows, fields) => {
  if (err instanceof Error) {
    console.log(err);
    return;
  }

  console.log(rows, fields);
});

---

Glossary

PoolOptions

PoolOptions extends all options from ConnectionOptions:

ConnectionOptions Specification

PoolOptions Specification