Method Close

pgconn/pgconn.go:738–768

Close closes a connection. It is safe to call Close on an already closed connection. Close attempts a clean close by sending the exit message to PostgreSQL. However, this could block so ctx is available to limit the time to wait. The underlying net.Conn.Close() will always be called regardless of an

(ctx context.Context)

// sending the exit message to PostgreSQL. However, this could block so ctx is available to limit the time to wait. The
// underlying net.Conn.Close() will always be called regardless of any other errors.
func (pgConn *PgConn) Close(ctx context.Context) error {
	if pgConn.status == connStatusClosed {
		return nil
	}
	pgConn.status = connStatusClosed

	defer close(pgConn.cleanupDone)
	defer pgConn.conn.Close()

	if ctx != context.Background() {
		// Close may be called while a cancellable query is in progress. This will most often be triggered by panic when
		// a defer closes the connection (possibly indirectly via a transaction or a connection pool). Unwatch to end any
		// previous watch. It is safe to Unwatch regardless of whether a watch is already is progress.
		//
		// See https://github.com/jackc/pgconn/issues/29
		pgConn.contextWatcher.Unwatch()

		pgConn.contextWatcher.Watch(ctx)
		defer pgConn.contextWatcher.Unwatch()
	}

	// Ignore any errors sending Terminate message and waiting for server to close connection.
	// This mimics the behavior of libpq PQfinish. It calls closePGconn which calls sendTerminateConn which purposefully
	// ignores errors.
	//
	// See https://github.com/jackc/pgx/issues/637
	pgConn.frontend.Send(&pgproto3.Terminate{})
	pgConn.flushWithPotentialWriteReadDeadlock()

	return pgConn.conn.Close()
}

// asyncClose marks the connection as closed and asynchronously sends a cancel query message and closes the underlying
// connection.