Hello all,

last week we experienced some strange problems with our firebird
server. Any connections were refused while the number of fbserver
processes is rising. Details:

- FirebirdSS-1.5.2.4731-0 running on SuSE Standard Server 8 with
kernel k_smp-2.4.21-273
- Clients are various selfmade applications written in Borland Delphi

Wednesday morning we got some error reports that the DB refuses any
connections. We found that there were more than 1000 fbserver
processes running (usually < 20). Stopping firebird, killing all
processes and restarting made everything work again. In the
firebird.log we found a number of "INET/inet_error: read errno = 104".
We never had such trouble in the last 2 years, so we just thought:
Sometimes shit happens, kept an eye on the number of fbserver
processes, but everything was fine for the next few days.

On saturday I had to shut down the server for some maintenance,
unrelated to fb. The shutdown process hung several minutes on shutting
down the firebird server. SSH was still working, so I could log on and
found the usual number of fbserver processes. When I killed one of
them the shutdown process continued. Nothing in the log - only one
line "bin/fbserver terminated abnormally" because of my "kill" command.

After finishing maintenance the server was restarted. I checked if fb
was working with one of our Delphi DB client applications. Everything
OK. Half an hour later when I had left, our network monitoring tool
nagios (see www.nagios.org) threw some messages like "Firebird Service
Check Timed Out". I could see in the system statistics of the SuSE
StdS8 that the number of processes increased from this time on to
about 1000 within 14 hours. Monday morning we were in trouble again.
No connection possible. So again I did "rcfirebird stop" and "killall
fbserver". Here's the part of firebird.log from startup on saturday to
"killall" on monday morning:

samba1 (Client) Sat Mar 18 17:31:48 2006
/opt/firebird/bin/fbguard: guardian starting bin/fbserver
samba1 (Client) Mon Mar 20 07:59:54 2006
INET/inet_error: read errno = 104
samba1 (Client) Mon Mar 20 07:59:54 2006
INET/inet_error: receive in try_connect errno = 104
samba1 (Client) Mon Mar 20 08:00:53 2006
/opt/firebird/bin/fbguard: bin/fbserver terminated abnormally (-1)

Nothing in /var/log/messages or /var/log/warn.

We have some processes on different clients that try to connect to the
database every few minutes: nagios and two of our own Delphi apps.
Something seems to go wrong in a way that every db connection gets
refused and each connection attempt leaves an fbserver process in memory.

My questions:
- What does the error code 104 in the log mean? I also find some
errno=4 and 9 in the logs. On firebird.sourceforge.net I could only
find the SQL error table. Where's the documentation for the error
codes in the logfile?

- Does anybody have an idea what could cause this behaviour? And how
to fix it?

Thank you,

Mario Balfanz
FAFNIR GmbH
Hamburg, Germany