Hi,

I'm using DBCP for JNDI-accessed connection pooling with mySQL and
Connector/J in a Tomcat 5-based application.

Can anyone tell me where I can find recommendations/guidelines for choosing
values for the DBCP parameters -- such as maxActive, maxIdle, maxWait,
etc. -- in the ResourceParams element of server.xml?

For example, I am about to launch a system that has a user base of approx
7000 users, which I expect will be thrashed hard at launch time and then
settle down to an average of 10 to 100 users at any given time. But what are
the best values to specify for my database pooling parameters?

Thanks,

Frank.


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Frank Burns wrote:

within Turbine... Believe it or not its a LOT more robust than the
latest release which has a number of bugs. I'd recommend not using DBCP
but thats just me (even though I'm an Apache developer and it hurts me
to say it).

Anyway...

We have a multithreaded app with about 400 concurrent connections
pounding the box with only 20 maxActive connections and it works great.

Another note... DBCP has a bug with multithreaded code. Init your
threadpool in one static thread and then get connection up until
maxActive and then release them all. It has a terrible bug where it
will get confused and isn't able to expand the pool anymore. ...

Anyway

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Frank Burns wrote:

much. I'd rather use the memory for HEAP tables or index cache.

The problem is that each conn on the server uses about 5M so if you have
a gig to use then go for it but its overkill.

.... anyway..

maxIdle I set to 0 ... I don't want it closing connections.

maxWait I set to 60000.... but that might be too long.

Also look at this:

http://www.mysql.com/documentation/c...r-j/#id2801179

The JDBC driver itself has some important options especially the
PreparedStatement cache stuff.

think a workaround is just to create all threads on init in one thread.

Also note that the documentation for DBCP is wrong... maxWait, maxIdle,
and maxActive are really only the pool options you can set. Everything
else is experimental.

The sad thing is that I'm probably going to have to take DBCP and start
from scratch and maybe create a DBCP 2.0.... but I don't have time for
that right now

Peace!

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