Hi Evgeny,
that is something that should rarely happen. If you create a schema object like a table, others could do the same from other sessions. That's no problem as long as there is no attempt to create two objects with the same name. One possible scenario: You turn autocommit off in one session, then create table t there without commit. Another session creates table t in the same schema. Now you try to commit in the first session. That causes a schema conflict. If both session were on autocommit ON , the first create table t succeeds and the second fails with the normal error message.
