DB2 jdbc performance

Question

doing profiling on an java application running websphere 7 and DB2 we can see that we spend most of our time in the com.ibm.ws.rsadapter.jdbc package handling connections to and from the database.

1. How can we tune our jdbc performance?

2. What other strategies exist when database performance is a bottleneck?

Thanks

Answer 1

You should check yourwebsphere manual for how you configure a connection pool.

Update 2021

Here is an introduction inculding code samples

Update 2021

Answer 2

One cause of slow connect times is a deactivated database, which does not open its files and allocate its memory buffers and heaps until the first application attempts to connect to it. Ask your DBA to confirm that the database is active before running your tests. The LIST ACTIVE DATABASES command (run from the local DB2 server or over a remote attachment) should show your database in its output. If the database is not activated, have your DBA activate it explicitly with ACTIVATE DATABASE yourDBname. That will ensure that the database files and memory structures remain available even when the last user disconnects from the database.

Use GET MONITOR SWITCHES to ensure all your monitor switches are enabled for your database, otherwise you'll miss out on some potentially revealing performance details. The additional overhead of tracking the data associated with those monitor switches is minimal, while the value of the performance data is significant.

If the database is always active and things still seem slow, there are detailed DB2 traces called event monitors that log everything they encounter to a file, pipe, or DB2 table. The statement event monitor is one I turn to fairly often to analyze SQL statement efficiency and UOW hygiene. I also prefer taking the extra hit to log the event monitor records to a table rather than a file, so I can use SQL to search the data for all sorts of patterns. The db2evtbl utility makes it fairly easy to define the event monitor you want and create the tables to store its output. The SET EVENT MONITOR STATE command is how you start and stop the event monitor you've created.

Answer 3

In my experience what you are seeing is pretty common. The question to ask is what exactly is the DB2 connection doing...

The first thing to do is to try and isolate the performance issue down to a section of the website - ie is there one part of the application that see poor performance, when you find that you can increase the trace logging to see if you can see the query causing issues.

Additionally, if you chat to your DBA's they may be able to run some analysis on the database to tell you what queries are taking the time to return values, this may also help in your troubleshooting.

Good luck!

Answer 4

• Connection pooling
• Caching
• DBAs