Hey, Explaining the whole infrastructure may be even more confusing. so I'll ask something else, simpler- when using the string testonborrow="true" do I need to use it alone? can it be used alone? or do I have to put also the validationInterval string (or any other string)?
Thanks Hila 2011/5/20 André Warnier <a...@ice-sa.com> > הילה wrote: > ... > > >> So, if you are using that pool, I basically do not understand why you >>> would >>> need any additional mechanism to overcome the loss of a db connection >>> when >>> your VM is migrated. >>> Particularly that "smart keep alive" you keep talking about, but never >>> telling us where it comes from and where it is inserted in that >>> architecture. >>> >>> I don't understand on what mechanism are you talking about. I don't want >>> to >>> >> add anything (unless it can fix the problem) >> I just stated the problem, and the environment we have (win 2008, tomcat >> 6.0.29, jdbc pool.. These are the dry facts) >> >> The keep alive is an xslt file which contains actions to perform on the DB >> to check that everything is alive. >> if so, it returns an OK response, which can be viewed in HTML file on IE >> browser. >> The Load balancer samples the keep alive every 10 seconds to check the OK >> state. if it's not OK for 3 times in a row- the LB takes it out from the >> servers' pool and no one else can connect to it. >> > > So now there is also a load balancer ? I've just gone through all your > previous posts, and this is the first time it has been mentioned. > And it appears that it is the load balancer which tests de DB server > directly (?) > Huh ? I'm like Chris now, just a bit confused again about your setup. > > > so yes. we need this keep alive and can't dismiss it, because it's the >> indication that the server is functioning properly. >> > > Which server ? > > > and if it's not function > >> - The LB can identify it and remove the server from the servers' pool so >> no >> one will try and approach it. >> >> > Again, which server is taken out of the server pool ? The DB server, or > the one running Tomcat ? > > Do you actually mean that the load balancer on one side, and Tomcat on the > other side, are each accessing the DB server in parallel and by different > channels ? > > > >>> we use the JTDS driver (I tried the Microsoft JDBC, but its performance >>>> is >>>> poor compared to the JTDS driver of sourceforge) >>>> Someone in my company suggested that the problem can rely in either of >>>> these >>>> JARs. >>>> so I will check with the tomcat-dbcp.jar as scenario 1, sql-jdbc.jar as >>>> scenario2, and maybe both combined as scenario 3. >>>> scenario 4 will be testing the behavior while validation is configured. >>>> >>>> >>>> Sure, add some extra variables to the problem. That will make it a lot >>> simpler to find out what happens. >>> >>> no need of sarcasm here. these aren't additional variables. we spoke on >>> the >>> >> connection pool, so this is one of the things I can focus on to try and >> fix >> the problem. >> >> Yes, that was sarcasm. I was just getting a bit frustrated, because I am > trying to help, but it seems impossible to get logical explanations here > even about your exact configuration. > > So let me try again, graphically. > As far as I can tell by your posts, your configuration is : > > hardware : > - Vmware VM with your application and Tomcat and jdbc pool and jtds drivers > - network > - another machine with the DB > > and, somewhere, there is a load-balancer with a "smart keep alive" feature > built-in. > > logical : > > Application <--> Tomcat <--> jdbc pool <--> jtds driver <--> network <--> > database > > At the start, the jdbc pool contains for example 10 connections to the > database. > At some point, there is a network problem, and as a consequence 5 of these > connections are broken. But the jdbc pool is not configured to detect this > in advance, and as a consequence, when the application tries to use a DB > connection, it may get one of the 5 pooled connections which are broken, and > it then gets an exception and breaks down. > Or it may get a pooled connection that is not broken, and then everything > appears to work fine. > > Now can you tell us where in the above schema the "smart keep alive" fits > in ? > > Or else, correct the above schema to tell us how things really work ? > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > >
