internal bool CheckForContextSocketAvailability (NpgsqlConnector context, SelectMode selectMode)
{
/* Socket.Poll supports integer as microseconds parameter.
* This limits the usable command timeout value
* to 2,147 seconds: (2,147 x 1,000,000 < max_int).
*/
const int limitOfSeconds = 2147;
bool socketPoolResponse = false;
// Because the backend's statement_timeout parameter has been set to context.Mediator.BackendCommandTimeout,
// we will give an extra 5 seconds because we'd prefer to receive a timeout error from PG
// than to be forced to start a new connection and send a cancel request.
// The result is that a timeout could take 5 seconds too long to occur, but if everything
// is healthy, that shouldn't happen. Not to mention, if the backend is unhealthy enough
// to fail to send a timeout error, then a cancel request may malfunction anyway.
int secondsToWait = context.Mediator.BackendCommandTimeout + 5;
/* In order to bypass this limit, the availability of
* the socket is checked in 2,147 seconds cycles
*/
while ((secondsToWait > limitOfSeconds) && (!socketPoolResponse))
{
socketPoolResponse = context.Socket.Poll (1000000 * limitOfSeconds, selectMode);
secondsToWait -= limitOfSeconds;
}
return socketPoolResponse || context.Socket.Poll (1000000 * secondsToWait, selectMode);
}
