Connection Pooling

External connections made by statements WITH COMMON TRANSACTION (the default) will remain open until the current transaction ends.They can be reused by subsequent calls to EXECUTE STATEMENT, but only if connection_string is identical, including case

External connections made by statements WITH AUTONOMOUS TRANSACTION are closed as soon as the statement has been executed

Statements using WITH AUTONOMOUS TRANSACTION can and will re-use connections that were opened earlier by statements WITH COMMON TRANSACTION.If this happens, the reused connection will be left open after the statement has been executed.(It must be, because it has at least one active transaction!)

If WITH COMMON TRANSACTION is in effect, transactions will be reused as much as possible.They will be committed or rolled back together with the current transaction

If WITH AUTONOMOUS TRANSACTION is specified, a fresh transaction will always be started for the statement.This transaction will be committed or rolled back immediately after the statement’s execution