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I have a DBCP connection pool in Tomcat. The problem is that when the connection is lost briefly the appliction is broken because DBCP won't try to reconnect again later when there is a connection. Can I get DBCP to reconnect automatically?
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To check for reconnection, call mysql_thread_id() to get the original connection identifier before calling mysql_ping() , then call mysql_thread_id() again to see whether the identifier changed.
MySQL has its wait_timeout variable default value set to 28800 seconds (8 hours).
Connection pooling enables the idle connection to be used by some other thread to do useful work. In practice, when a thread needs to do work against a MySQL or other database with JDBC, it requests a connection from the pool.
There are 2 ways to "solve" this, though both have some issues:
You can use a "validationQuery" (see below) to have a test query run before you go (generally something like 'select 1 from dual' which will be used to test connections before/after you get/give them to the pool. This adds an extra call per connection request from the pool. See: http://wiki.apache.org/commons/DBCP
Instead of doing this per query, you can have the idleEvictorThread do it by setting testWhileIdle, though in some versions that thread can cause deadlocking under high-load. See: http://commons.apache.org/dbcp/configuration.html for more details on that and other options
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Don't think DBCP does that, but BoneCP (http://jolbox.com) can be configured to automatically replay any transactions when the DB or network goes down. It's completely transparent to your application.
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