IBM BPM, V8.0.1, All platforms > Tuning > Advanced tuning > Tuning for maximum concurrency
Set DataSource prepared statement cache size
The Business Process Choreographer container uses prepared statements extensively. The statement cache sizes must be large enough to avoid repeatedly preparing statements for accessing the databases.
The prepared statement cache for the BPEDB data source must be at least 128.
See the following developerWorks article: 
http://www.ibm.com/developerworks/websphere/library/techarticles/0912_grundler/0912_grundler.html.