Built-in Clients

Parallel queries need a non-blocking database client. PDO has none, and the PHP extensions that do (mysqli, pgsql) are often disabled on shared hosting, and there is no such extension at all for SQL Server. So MikoORM includes its own clients for the MySQL, PostgreSQL and SQL Server (TDS) wire protocols, written in plain PHP. With them, async queries run in parallel without installing anything.

Which client is used

Choose per driver with the mysql_driver, pgsql_driver and sqlsrv_driver settings (DB_ASYNC_MYSQL_DRIVER ... in .env, or Async::configure([...])). The normal (sync) queries always use PDO.

The clients need only PHP's stream sockets, plus openssl for encrypted connections and mbstring for SQL Server.

Same results as PDO

The clients convert values the way the PDO drivers do, so a query returns identical rows whether it ran sync or async:

Errors carry the same driver code and SQLSTATE (isDuplicateEntry(), isForeignKeyError() ... work the same). Speed is on par with the extensions: in local measurements 50,000 PostgreSQL rows took 115 ms with the built-in client and 117 ms with pgsql.

MySQL / MariaDB

$connection = ConnectionFactory::make([
    'driver' => 'mysql', 'host' => 'db.example.com', 'database' => 'app',
    'username' => 'app', 'password' => 'secret',
    'options' => [PDO::MYSQL_ATTR_SSL_CA => '/etc/ssl/certs/db-ca.pem'],   // PDO and async connections
]);

MariaDB users that only allow auth_gssapi_client / unix_socket plugin logins need mysqli.

PostgreSQL

$connection = ConnectionFactory::make([
    'driver' => 'pgsql', 'host' => 'db.example.com', 'database' => 'app',
    'username' => 'app', 'password' => 'secret',
    'sslmode' => 'verify-full', 'sslrootcert' => '/etc/ssl/certs/db-ca.pem',
]);

The SSL keys are also added to the PDO DSN, so sync and async connections use the same settings.

SQL Server

$connection = ConnectionFactory::make([
    'driver' => 'sqlsrv', 'host' => 'sql.example.com', 'port' => 1433, 'database' => 'app',
    'username' => 'app', 'password' => 'secret',
    'encrypt' => true, 'trust_server_certificate' => false,
]);

The sync queries still need pdo_sqlsrv and an ODBC driver; only the async queries use the built-in client.

SQLite

SQLite is a file, not a server: there is nothing to run queries in parallel on. Async methods there run one by one on the main connection and return the same results, so code written with ...Async() works on every database.

Troubleshooting

Force one client to compare: Async::configure(['pgsql_driver' => 'php']) or 'extension'.