Class NpgsqlMultiHostDataSource

Namespace

Npgsql

Assembly

Npgsql.dll

An NpgsqlDataSource which manages connections for multiple hosts, is aware of their states (primary, secondary, offline...) and can perform failover and load balancing across them.

public sealed class NpgsqlMultiHostDataSource : NpgsqlDataSource, IDisposable, IAsyncDisposable

Inheritance

object

DbDataSource

NpgsqlDataSource

NpgsqlMultiHostDataSource

Implements

IDisposable

IAsyncDisposable

Inherited Members

NpgsqlDataSource.ConnectionString

NpgsqlDataSource.CreateConnection()

NpgsqlDataSource.OpenConnection()

NpgsqlDataSource.OpenConnectionAsync(CancellationToken)

NpgsqlDataSource.CreateCommand(string)

NpgsqlDataSource.CreateBatch()

NpgsqlDataSource.Create(string)

NpgsqlDataSource.Create(NpgsqlConnectionStringBuilder)

NpgsqlDataSource.Password

DbDataSource.Dispose()

DbDataSource.DisposeAsync()

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

See https://www.npgsql.org/doc/failover-and-load-balancing.html.

Methods

Clear()

If the data source pools connections, clears any idle connections and flags any busy connections to be closed as soon as they're returned to the pool.

public override void Clear()

ClearDatabaseStates()

Clears the database state (primary, secondary, offline...) for all data sources managed by this multi-host data source. Can be useful to make Npgsql retry a PostgreSQL instance which was previously detected to be offline.

public void ClearDatabaseStates()

CreateConnection(TargetSessionAttributes)

Returns a new, unopened connection from this data source.

public NpgsqlConnection CreateConnection(TargetSessionAttributes targetSessionAttributes)

Parameters

targetSessionAttributes TargetSessionAttributes

Specifies the server type (e.g. primary, standby).

Returns

NpgsqlConnection

OpenConnection(TargetSessionAttributes)

Returns a new, opened connection from this data source.

public NpgsqlConnection OpenConnection(TargetSessionAttributes targetSessionAttributes)

Parameters

targetSessionAttributes TargetSessionAttributes

Specifies the server type (e.g. primary, standby).

Returns

NpgsqlConnection

OpenConnectionAsync(TargetSessionAttributes, CancellationToken)

Returns a new, opened connection from this data source.

public ValueTask<NpgsqlConnection> OpenConnectionAsync(TargetSessionAttributes targetSessionAttributes, CancellationToken cancellationToken = default)

Parameters

targetSessionAttributes TargetSessionAttributes

Specifies the server type (e.g. primary, standby).

cancellationToken CancellationToken

An optional token to cancel the asynchronous operation. The default value is None.

Returns

ValueTask<NpgsqlConnection>

WithTargetSession(TargetSessionAttributes)

Returns an NpgsqlDataSource that wraps this multi-host one with the given server type.

public NpgsqlDataSource WithTargetSession(TargetSessionAttributes targetSessionAttributes)

Parameters

targetSessionAttributes TargetSessionAttributes

Specifies the server type (e.g. primary, standby).

Returns

NpgsqlDataSource