Well, I did the post-mortem. It's not a communication thing, the DB and WK are on the same machine. WK reported no errors whatsoever. However, the apache logs are full of "failure connecting to appserver attempt X out of 10" (or something akin to that). MySQL also has reported nothing. Looking at the logs, the MySQL error I reported below seems to be unrelated (although I am definitely doing something wrong with these connections; any literature guys?).
So, long story short it seems that WK just gave up. Now, I got an idea/request: since I am using mod_webkit (linux), how hard would it be to rig mod_webkit up to restart the WK appserver if it has failed to connect after X attempts? Thanks for the help everybody. I've been googling for some good reference on how to manage DB connections on a DB-backed website and I've only come across pretty basic stuff. Any pointers? Thanks, Costas >From: "Aaron Held" <[EMAIL PROTECTED]> >To: "Costas Malamas" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> >CC: <[EMAIL PROTECTED]> >Subject: Re: [Webware-discuss] Webkit hangs after MySQL error >Date: Fri, 8 Feb 2002 17:35:19 -0500 > >I had a similar problem. >When I ran webkit on a Win2k server and connected to a Linux >database through a firewall the connection would be cut off every >night. >Turned out to be a firewall rule. I can keep the conn open now, >but if the connection gets severed then the webkit app hangs. > >I have not had time to address this yet, but its a problem. > >-Aaron >----- Original Message ----- >From: "Costas Malamas" <[EMAIL PROTECTED]> >To: <[EMAIL PROTECTED]> >Cc: <[EMAIL PROTECTED]> >Sent: Thursday, February 07, 2002 6:34 PM >Subject: Re: [Webware-discuss] Webkit hangs after MySQL error > > > > > > I still haven't been able to ssh in, but it certainly looked >like the > > appserver was down, as no servlet was responding. A friend >restarted WK and > > all is fine now, so... > > > > Any pointers as to how I can make the connection more robust? >Is it worth > > re-using the connection, or should I re-initialize it in the >servlet's > > __init__(), for example? If not, is there a way to test the >connection and > > restart it if it's dead (maybe wrap it in a try/except)? > > > > I guess if there was a way I could intentionally "starve" WK so >I can try > > out different tactics, that would be even more useful. > > > > Thanks, > > > > Costas > > > > > > > > >From: Ian Bicking <[EMAIL PROTECTED]> > > >To: Costas Malamas <[EMAIL PROTECTED]> > > >CC: [EMAIL PROTECTED] > > >Subject: Re: [Webware-discuss] Webkit hangs after MySQL error > > >Date: 07 Feb 2002 12:19:26 -0600 > > > > > >There's a possibility that, because your website got a lot of >hits some > > >resource was exhausted (memory, maybe), and that could cause >multiple > > >problems. I.e., whatever closed the connection also caused WK >to crash. > > > > > >Alternatively, I imagine there's also a number of reasons why >a MySQL > > >connection could be lost: does your application open a new >connection if > > >this happens? > > > > > >And, lastly, is the AppServer gone, or are your servlets just >not > > >responding? If the AppServer is gone, it would definitely be >a bug in > > >WK (though I don't know what it could do if you run out of >memory -- > > >though that would be a sign that WK needs to do more to >preserve > > >memory). But if your servlets can't recover from the failure >at other > > >points -- like the MySQL connection -- then you'd have to make >those > > >portions more robust. > > > > > >On Thu, 2002-02-07 at 05:40, Costas Malamas wrote: > > > > I am trying to diagnose a WebKit crash: my website got a >large number of > > > > hits yesterday, and apparently WK crashed completely. WK >is connected > > >to > > > > MySQL on the backend, and the last thing I saw from WK (I >cannt telnet > > >to > > > > the box to do forensics on WK yet) was a MySQL error: "lost >connection > > >to > > > > the database". > > > > > > > > Now, MySQL is still up and running (I am using phpmyadmin >so I am sure > > >the > > > > system's OK), but I am trying to figure out why WK reacted >so badly. > > > > > > > > One possible reason: in my classes, I am opening a single >mysql > > >connection > > > > that's instantiated once and passed around to every >DB-dependant class. > > >Is > > > > it possible that a WK crash closed this connection and then >the servlets > > > > cannot re-open it? if so, is there a work-around for this? > > > > > > > > Even more general, possible OT: am I better off >performance wise, to > > >re-use > > > > the same DB connection, or instead open up one per-servlet >instance or > > > > something? > > > > > > > > Thanks, > > > > > > > > Costas > > > > > > > > > > > > > > > > >_________________________________________________________________ > > > > Join the world's largest e-mail service with MSN Hotmail. > > > > http://www.hotmail.com > > > > > > > > > > > > _______________________________________________ > > > > Webware-discuss mailing list > > > > [EMAIL PROTECTED] > > > > >https://lists.sourceforge.net/lists/listinfo/webware-discuss > > > > > > > > > > > > > > > > >_________________________________________________________________ > > Join the world's largest e-mail service with MSN Hotmail. > > http://www.hotmail.com > > > > > > _______________________________________________ > > Webware-discuss mailing list > > [EMAIL PROTECTED] > > https://lists.sourceforge.net/lists/listinfo/webware-discuss > > _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp. _______________________________________________ Webware-discuss mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/webware-discuss
