Performance comparison of JDBC connection pools

Question

Does anyone have any information comparing performance characteristics of different ConnectionPool implementations?

Background: I have an application that runs db updates in background threads to a mysql instance on the same box. Using the Datasource com.mchange.v2.c3p0.ComboPooledDataSource would give us occasional SocketExceptions: com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception:

** BEGIN NESTED EXCEPTION ** 

java.net.SocketException
MESSAGE: Broken pipe

STACKTRACE:

java.net.SocketException: Broken pipe
        at java.net.SocketOutputStream.socketWrite0(Native Method)

Increasing the mysql connection timeout increased the frequency of these errors.

These errors have disappeared on switching to a different connection pool (com.mysql.jdbc.jdbc2.optional.MysqlConnectionPoolDataSource); however the performance may be worse and the memory profile is noticeably so (we get fewer, and much larger, GC's than the c3p0 pool).

Answer 1

Whatever connection pool you use, you need to assume that the connection could be randomly closed at any moment and make your application deal with it.

In the case with a long-standing DB connection on a "trusted" network, what often happens is that the OS applies a time limit to how long connections can be open, or periodically runs some "connection cleanup" code. But the cause doesn't matter too much -- it's just part of networking life that you should assume the connection can be "pulled from under your feet", and deal with this scenario accordingly.

So given that, I really can't see the point of a connection pool framework that doesn't allow you to handle this case programmatically.

(Incidentally, this is another of my cases where I'm glad I just write my own connection pool code; no black boxes mysteriously eating memory, and no having to fish around to find the "magic parameter"...)

Answer 2

You may want to have a look at some benchmark numbers up at http://jolbox.com - the site hosting BoneCP, a connection pool that is faster than both C3P0 and DBCP.