What did Alfresco Support say? Since this is an Enterprise-only supported database and an Enterprise Edition release, they should be the first to contact.
Having said that, any request / background processing job will trigger the initialisation of a DB transaction for the sake of isolation from other concurrent operations. Now unfortunately the initialisation of the transaction is automatic and unaware of what a specific piece of code may choose to do. There are cases / operations that determine they don't need to do anything after having caused the transaction to be initialised, which ends up looking like superflous chatter. In some cases the code checking if something needs to be done actually intends for a database interaction to occur, but because Alfresco may cache data in second level caches won't actually end up calling the database.
There are a number of known reasons / patterns that can cause this chattiness. It would need correlation with operations running in your system and the configuration of the system to pinpoint individual code lines that could be optimised to reduce chatter. But we will likely never eliminate it alltogether.
