[las_users] TOMCAT and MySQL connection settings and killing of outdated PIDS.

[Jerome King <jejeking@xxxxxxxxxxx>]

Hi LAS users and experts!

I have several LAS using a TOMCAT server independant from the LAS. Meaning, 
the LAS are not using the TOMCAT server that comes bundled within the LAS 
install package. Also all of those LAS are connected to different RDBMS 
MySQL databases.

For sometime now, I have had problems where I would get errors on the output 
page of the LAS every 1 out of 3 queries I would make in LAS. If I reloaded 
the constraint page, I would get a "java.sql.SQLException  MESSAGE: Too many 
connections" error.

After some research, it seems that after TOMCAT or/and MySQL reaches a 
certain number of connections, TOMCAT or/and MySQL stop making connection to 
the LAS.

I increased the default number for "max_connection" in my.cnf from 100 to 
250 in MySQL and "maxThreads" and "acceptCount" also to larger numbers in 
server.xml of the TOMCAT. The problem seems to have stopped.

I was wondering if you guys know about how to best set those settings so it 
works well with the LAS?
Maybe you could recommend the best values for those settings for a LAS which 
is being access regularly by multiple users at the same time therefore 
making many connection to a MySQL database?
Also, I was wondering if you are setting those value before bundling TOMCAT 
within the LAS install package?

Another issue is how to deal with the outdated TOMCAT and MySQL PIDs that do 
not get killed after LAS is done with the query.
After a bit of research, it seems that this can be controlled by setting a  
Database Connection Pool (DBCP) configuration.

Before I research all of this more, I was wondering if any of you looked 
into this more and what is the best method to control TOMCAT and MySQL 
connection to LAS.

Thanks a lot for your insight!
Jerome.