Metrics

MySqlConnector exposes metrics that follow the OpenTelemetry Semantic Conventions for Database Metrics via types in the System.Diagnostics.Metrics namespace.

Metrics are only supported in MySqlConnector 2.3.0 or later.

The name used for the meter is MySqlConnector.

Connect a listener using the MeterListener class:

new MeterListener
{
    InstrumentPublished = (instrument, listener) =>
    {
        if (instrument.Meter.Name == "MySqlConnector")
            listener.EnableMeasurementEvents(instrument);
    }
};

Supported Instruments

Name	Type	Unit	Description
`db.client.connections.usage`	UpDownCounter	`{connection}`	The number of connections that are currently in the state described by the state tag.
`db.client.connections.pending_requests`	UpDownCounter	`{request}`	The number of pending requests for an open connection, cumulative for the entire pool.
`db.client.connections.timeouts`	Counter	`{timeout}`	The number of connection timeouts that have occurred trying to obtain a connection from the pool.
`db.client.connections.create_time`	Histogram	`s`	The time it took to create a new connection.
`db.client.connections.use_time`	Histogram	`s`	The time between borrowing a connection and returning it to the pool.
`db.client.connections.wait_time`	Histogram	`s`	The time it took to obtain an open connection from the pool.
`db.client.connections.idle.max`	UpDownCounter	`{connection}`	The maximum number of idle open connections allowed; this corresponds to `MaximumPoolSize` in the connection string.
`db.client.connections.idle.min`	UpDownCounter	`{connection}`	The minimum number of idle open connections allowed; this corresponds to `MinimumPoolSize` in the connection string.
`db.client.connections.max`	UpDownCounter	`{connection}`	The maximum number of open connections allowed; this corresponds to `MaximumPoolSize` in the connection string.

Supported Tags

Name	Description
`pool.name`	The name of the connection pool (see below).
`state`	`idle` or `used`; this tag is used with the `db.client.connections.usage` instrument.

Connection Pool Name

A connection pool name can be specified by one of the following means:

UseName

The MySqlDataSourceBuilder.UseName method can be used to specify a name for the connection pool:

using var dataSource = new MySqlDataSourceBuilder("...connection string...")
    .UseName("MyPoolName")
    .Build();

This can also be used with dependency injection:

builder.Services.AddMySqlDataSource(builder.Configuration.GetConnectionString("Default"),
    x => x.UseName("MyPoolName"));

Keyed Services

Use the AddKeyedMySqlDataSource method to register a MySqlDataSource as a keyed service. If the service key is a string, it will automatically be used as the MySqlDataSource name.

builder.Services.AddKeyedMySqlDataSource("MyPoolName",
    builder.Configuration.GetConnectionString("MyConnectionString"));

Application Name

Finally, the connection pool name can be specified by setting the Application Name connection string option:

using var connection = new MySqlConnection("server=dbserver;...;Application Name=MyPoolName");

If UseName is used, it will override the Application Name connection string option.

Default

For metrics, if no pool name is specified, the connection string (without a password) will be used as the pool name.