[MSSQL] Snapshot transaction isolation level cannot be used with inTransaction methods

[mjadczak]

The Microsoft SQL Server JDBC driver defines a custom value for the SNAPSHOT transaction level which is unique to SQL Server.

Because the methods on JDBI and Handle objects which allow setting an isolation level, like inTransaction, require a parameter of type TransactionIsolationLevel, which is an enum defined directly by JDBI, this special value cannot be passed in, and we must instead set the default isolation level on the DataSource, or manually manage the handle's lifetime and use the setTransactionLevel override which allows specifying an int, neither of which are ideal.

Some immediate ideas for solutions are:

• add an override for these methods which takes a raw int directly
• change TransactionIsolationLevel to admit extension in some way - whether ad-hoc by the user, or by registering some sort of config or extension with the JDBI instance

[stevenschlansker]

Thanks for reporting this.