Task to begin a transaction. Note that this task does not properly set the
transaction isolation but this is not a real issue since it is meant to be
used by the recovery log that does not execute reads and provide its own
serial order.
Begins a new transaction given a login and a transaction id.
Parameters: nbToComplete - number of threads that must succeed before returning Parameters: totalNb - total number of threads Parameters: tm - transaction metadata throws: NullPointerException - if tm is null
Begins a new transaction with the given backend thread.
Parameters: backendThread - the backend thread that will execute the task exception: SQLException - if an error occurs