Hi all,
I've been using the libpq asynchronous functions to hook up database
calls into my event loop, and I've noticed a problem and was hoping
someone might know the solution.
The problem is that I have to unregister the file descriptor from the
event loop whenever the postgres connection fails, but often by the
time I notice it has failed in the code, it has already closed its
socket and so I can't guarantee that if I close the previously opened
socket that it hasn't already been opened up by someone else.
Maybe an example will make it clearer:
void send_to_db(PGConn *conn, char *command)
{ PQsendQuery(conn, command);
if (PQstatus(conn) == CONNECTION_BAD) { Log(WARNING, "database connection disconnected");
/* By this point PQsocket() returns -1. Even if I keep a
reference to the socket number * it might have already been opened by another socket call. */
PQfinish(conn);
/* Call function to reconnect, but I should have already
deleted the file event callbacks for the postgres connection socket.
*/ }
}
Please let me know what the solution is, or if something isn't clear.
Thanks,
Tony