Toplink stop sending queries

Question

I have problems with a specific query that uses CONTAINS (intermedia) on a customer site's web interface. For some simple values looked by the query, the query seems to take forever to be handled by the DB.
But that's not the main problem. The user can continue to access the the rest of the site and the DB till it attempts a second time the query that failed before.
From that moment the parts of the web site that makes accesses to the DB stop responding till we stop and restart the server.
I looked at the logs we generate, no trace of exception of error reports. However the logs also list the queries made to the DB and I note that that after the second of the problematic queries not a single query is listed in the log. It's as if TOPLINK thinks that its connection(s) to the DB are all used and that he is waiting for them to become free again before sending more queries.
Does someone now how to make him dialog with the DB again?
Andr�

Answer 1

This is most likely occuring because the TopLink ServerSession defaults to using a read connection pool with 2 connections.
You can increase the read connection pool size through one of, useReadConnectionPool, useExclusiveReadConnectionPool.
i.e.
server.useReadConnectionPool(5, 5);
The read connection pool currently must be configured in code, not through the sessions.xml. So if you are using the sessions.xml you will need to use the preConnect session event to configure your ServerSession.
This problem is also related to a fix that was put into the 9.0.3.5. TopLink is suppose to use a non-exclusive read connection pool by default, so that this type of problem does not occur, the 9.0.3.5 patch fixes this problem.