I've got a bit of a problem. I added a fast SIGALRM handler in my
project to do various maintenance and this broke PQconnectStart().
Oct 23 21:56:36 james BlueList: connectDBStart() -- connect() failed:
Interrupted system call ^IIs the postmaster running (with -i) at
'archives.blue-labs.org' ^Iand accepting connections on TCP/IP port 5432?
PQstatus() returns CONNECTION_BAD, how can I reenter the connection
cycle or delay, more like, how do I differentiate between an actual
failure to connect and an interruption by signal? My alarm timer
happens much too frequently for this code to make a connection and
unfortunately I can't disable the alarm because it's used for bean
counting and other maintenance.
Thanks,
David
Code snippet:
...
/*
* play some tricks now, use async connect mode to find if the server
* is alive. once we've figured that out, disconnect and immediately
* reconnect in blocking mode. this mitigates the annoying hangs from
* using PQconnectdb which has no support for a timeout.
*/
conn=PQconnectStart(cstr);
if(!conn) {
dlog(_LOG_debug, "SQL conn is NULL, aborting");
return NULL;
}
do {
c++;
pgstat=PQstatus(conn);
switch (pgstat) {
case CONNECTION_STARTED:
dlog(_LOG_debug, "Connecting to SQL server...");
break;
case CONNECTION_MADE:
case CONNECTION_OK:
dlog(_LOG_debug, "Connected to SQL server in asynchronous
mode...");
break;
case CONNECTION_BAD:
dlog(_LOG_debug, PQerrorMessage(conn));
if(conn)
PQfinish(conn);
dlog(_LOG_warning, "failed to connect to server");
return NULL;
break;
default:
dlog(_LOG_debug, "pg conx state = %i", pgstat);
break;
}
if(pgstat==CONNECTION_MADE||CONNECTION_OK)
break;
if(c>15) {
if(conn)
PQfinish(conn);
dlog(_LOG_warning, "failed to connect to server, timed out");
return NULL;
}
req.tv_sec=1;
req.tv_nsec=0;
sleep(&req);
} while(1);
/*
* close it and reopen it in normal blocking mode
*/
PQfinish(conn);
conn=PQconnectdb(cstr);
...
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TIP 4: Don't 'kill -9' the postmaster
