[CAY-2637] Allow forcing a custom Connection for a transaction

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.2.B1
• Assignee: Nikita Timofeev
• Reporter: Andrus Adamchik
• Created: 28/Oct/19 08:41
• Updated: 02/Jun/21 15:16
• Resolved: 02/Jun/21 15:16

Description

Just identified a use case where Cayenne transaction management API falls short.

DFLib JDBCConnector allows manual transaction management. I am using Cayenne with DFLib for a multi-step data transformation process, with multiple commits within a transaction. Cayenne queries should be able to include intermediate results flushed to DB (but still not committed), so they need to run over the same Connection.

I was able to implement a custom solution that required wrapping both DataSource and Transaction in custom classes. I think we can simplify this for the end users. Some ideas:

• add the ability to pass an explicit DataSource (and/or Connection) to TransactionDescriptor. Expand ServerRuntime.performInTransaction(..) to take TransactionDescriptor (just like TransactionManager does).

• allow TransactionListener to provide its own connection, both in "willAddConnection" (so it can wrap passed connection), or in a separate new method that would allow to provide own Connection before Cayenne checks out one from its own DataSource.