Comments on: Firewall dropping Oracle database connections in WebSphere connection pool?

By: abt12

abt12 — Thu, 03 Dec 2009 22:17:26 +0000

Great information here. Thanks for taking the time to post guys. I first tried the validationQuery and testOnBorrow parameters from the post above but I still had issues after the change. The web application experiencing the problems is compiled and we don’t have the source. It could be a coding issue. I’m now going to try setting SQLNET.EXPIRE_TIME to 10 minutes in an attempt to prevent any “stale” connections.

By: Richard

Richard — Fri, 18 Sep 2009 15:29:33 +0000

We had the exact same issue on a setup that uses Tomcat in conjunction with the Apache DBCP component. The solution was to use the validationQuery configuration parameter in pair with testOnBorrow=true. So when a connection is interrupted by the Firewall. The next time the application needs to use a connection from the pool, the pool validate the connection before releasing it. If the connection is dead it simply remove it from the pool and use another existing one or create a new one if need be.

The validationQuery parameter value on Oracle that we are using “Select 1 from dual”

By: Vivek Agarwal

Vivek Agarwal — Tue, 07 Jul 2009 00:23:49 +0000

Doug, You are absolutely right that one of the options that we could have gone with is to change the connection pool configuration settings of unusedTimeout and reapTime such that the combo was lower than the firewall idle timeout setting, while ensuring that the minConnections was set to zero. The downside to this is that depending on usage patterns and firewall idle timeout setting, you may end up incurring the cost of creating new database connections too often impacting performance and defeating the purpose of the connection pool. The upside is that this solution works with any database (and is not dependent on an Oracle-specific setting), and in fact can be used on any kind of "object pool" that must maintain remote connections through a firewall. Thanks for raising this point! -Vivek.

By: Shared Experiences » links for 2009-07-06

Shared Experiences » links for 2009-07-06 — Mon, 06 Jul 2009 23:08:28 +0000

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By: Guido

Guido — Mon, 06 Jul 2009 20:18:06 +0000

We faced exactly the same problem and solve it like Doug mentioned.

By: Doug

Doug — Mon, 06 Jul 2009 18:04:04 +0000

Was one of the other options you tried just to allow the DataSource Connection Pool to drop down to zero held connections? That’s what we’ve always done to prevent these kinds of problems, but I have no idea which approach has better performance implications.

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Отучаем фаервол “срать” в буфер сообщений ядра :) | CetLot — Sun, 05 Jul 2009 12:57:15 +0000

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