Re: Cheapest way to poll for notifications?

> Right?

Right. The way I do it, very roughly:

Pqconnectdb(...)
PQexec( mDbConn, "listen notify" );
int dbsock = PQsocket( mDbConn );
mKq = kqueue();
struct kevent kev[1], kevs[1];
EV_SET( &kev[0], dbsock, EVFILT_READ, EV_ADD | EV_ENABLE, 0, 0, 0 );
kevent( mKq, kev, 1, NULL, 0, NULL );
while( true ) {
bool needsnotify = false;
int evtcnt = kevent( mKq, NULL, 0, kevs, 1, NULL );
if( evtcnt == 1 && kevs[i].filter == EVFILT_READ && kevs[i].ident ==
dbsock ) {
while( true ) {
PQconsumeInput( mDbConn );
PGnotify * notify = PQnotifies( mDbConn );
if( notify ) {
free( notify );
needsnotify = true;
}
else
break;
}
}

if( needsnotify )
// go off & query the db & handle updates here
}

Of course you could also use select to wait on the socket.

--
Scott Ribe
scott_ribe(at)killerbytes(dot)com
http://www.killerbytes.com/
(303) 722-0567 voice