[Dovecot] Database server failure causes endless loop

[Andy Shellam]

Hi,

I've just started setting up Dovecot 1.0.1, and made an error in my 
configuration, which I think has found a potential problem in Dovecot.

I'm using PostgreSQL authentication, and set the database host to 
"localhost", which PostgreSQL doesn't listen on, so libpq is throwing 
the standard "is the server running?" message.

The problem, however, is Dovecot isn't seeming to understand this, and 
is endlessly looping, trying to query it every 5 seconds.  My client 
(telnet during testing) is simply sitting there waiting for a response, 
which it's never going to get.  After about 5 minutes, Dovecot killed 
the connection, saying "* BYE Disconnected for inactivity."

If this was from an IMAP client, I'm guessing the client would time-out 
after so long when it doesn't get a response back.
Wouldn't it be more sensible for Dovecot to try PostgreSQL, say, 3 
times.  If unsuccessful, send the client an "internal server error" or 
something similar?  Otherwise if the database server failed, and the 
client tries to connect, it'd be waiting for at least a minute (or 
whatever the standard time-out interval is) before failing, whereas it'd 
be better to see almost instantly if the server's down.

Regards,

Andy.

Log output:

dovecot: Jul 01 11:31:03 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:03 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:03 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:08 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:08 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:08 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:13 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:13 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:13 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:18 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:18 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:18 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:23 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:23 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:23 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:28 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:28 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:28 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:33 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:33 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:33 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:38 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:38 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:38 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:43 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:43 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:43 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:48 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:48 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:48 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:53 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:53 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:53 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:31:58 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:31:58 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:31:58 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:32:03 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:32:03 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:32:03 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:32:08 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:32:08 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:32:08 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:32:13 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:32:13 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:32:13 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:32:18 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:32:18 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:32:18 Error: auth(default):     TCP/IP connections on 
port 5432?
dovecot: Jul 01 11:32:23 Error: auth(default): pgsql: Connect failed to 
<database>: could not connect to server: Connection refused
dovecot: Jul 01 11:32:23 Error: auth(default):     Is the server running 
on host "localhost" and accepting
dovecot: Jul 01 11:32:23 Error: auth(default):     TCP/IP connections on 
port 5432?