thd->options' OPTION_STATUS_NO_TRANS_UPDATE bit was not restored at the end of SF() invocation, where
SF() modified non-ta table.
As the result of this artifact it was not possible to detect whether there were any side-effects when
top-level query ends.
If the top level query table was not modified and the bit is lost there would be no binlogging.
Fixed with preserving the bit inside of thd->no_trans_update struct. The struct agregates two bool flags
telling whether the current query and the current transaction modified any non-ta table.
The flags stmt, all are dropped at the end of the query and the transaction.
handling of savepoints in stored routines.
Fixed ha_rollback_to_savepoint()/ha_savepoint()/ha_release_savepoint()
functions to properly handle savepoints inside of stored functions and
triggers.
Also now when we invoke stored function or trigger we create new savepoint
level. We destroy it at the end of function/trigger execution and return back
to old savepoint level.
We should not allow explicit or implicit transaction commits inside
of stored functions or triggers (so in autocommit mode we should not
do commits after execution of sub-statement).
Also since we don't support nested statement transactions in 5.0,
we shouldn't commit or rollback stmt transactions while we are inside
stored functions or triggers. This should be fixed in later (>=5.1)
releases.
