(race cond)
It was possible for one thread to interrupt a Data Definition Language
statement and thereby get messages to the binlog out of order. Consider:
Connection 1: Drop Foo x
Connection 2: Create or replace Foo x
Connection 2: Log "Create or replace Foo x"
Connection 1: Log "Drop Foo x"
Local end would have Foo x, but the replicated slaves would not.
The fix for this is to wrap all DDL and logging of a kind in the same mutex.
Since we already use mutexes for the various parts of altering the server,
this only entails moving the logging events down close to the action, inside
the mutex protection.
Column names weren't checked for uniqueness for subqueries.
Code for names uniqueness checking used for view creation moved into
separate function named check_duplicate_names(). It's called on
preparation of subqueries to check uniqueness of names. If duplicate names
are found then error is raised.
now default behaviour do not prevent any updates of view.
Also updating VIEWs of queries without LIMIT clause will not be checked at all (there will not be even warning)
(changes according to discussion on last dev-conf)
