SELECT ... WHERE ... IN (NULL, ...) does full table scan,
even if the same query without the NULL uses efficient range scan.

The bugfix for the bug 18360 introduced an optimization:
if
  1) all right-hand arguments of the IN function are constants
  2) result types of all right argument items are compatible
     enough to use the same single comparison function to
     compare all of them to the left argument,

then

  we can convert the right-hand list of constant items to an array
  of equally-typed constant values for the further
  QUICK index access etc. (see Item_func_in::fix_length_and_dec()).

The Item_null constant item objects have STRING_RESULT
result types, so, as far as Item_func_in::fix_length_and_dec()
is aware of NULLs in the right list, this improvement efficiently
optimizes IN function calls with a mixed right list of NULLs and
string constants. However, the optimization doesn't affect mixed
lists of NULLs and integers, floats etc., because there is no
unique common comparator.


New optimization has been added to ignore the result type
of NULL constants in the static analysis of mixed right-hand lists.
This is safe, because at the execution phase we care about
presence of NULLs anyway.

1. The collect_cmp_types() function has been modified to optionally
   ignore NULL constants in the item list.
2. NULL-skipping code of the Item_func_in::fix_length_and_dec()
   function has been modified to work not only with in_string
   vectors but with in_vectors of other types.

rpl.rpl_trigger.test fails with valgrind errors with the innodb plugin

The problem is that there is only one autoinc value associated with 
the query when binlogging. If more than one autoinc values are used 
in the query, the autoinc values after the first one can be inserted 
wrongly on slave. So these autoinc values can become inconsistent on 
master and slave.

The problem is resolved by marking all the statements that invoke 
a trigger or call a function that updated autoinc fields as unsafe, 
and will switch to row-format in Mixed mode. Actually, the statement 
is safe if just one autoinc value is used in sub-statement, but it's 
impossible to check how many autoinc values are used in sub-statement.)

                    Removes the need of a hack (the jump to label).

On Mac OS X or Windows, sending a SIGHUP to the server or a
asynchronous flush (triggered by flush_time), would cause the
server to crash.

The problem was that a hook used to detach client API handles
wasn't prepared to handle cases where the thread does not have
a associated session.

The solution is to verify whether the thread has a associated
session before trying to detach a handle.

Make configure.js bail with an error if trying to build bdb from a bzr
tree.

Copy mysql-stress-run.pl into noinstall package.

          'flush tables' crashes

The server crashes when 'show procedure status' and 'flush tables' are
run concurrently.

This is caused by the way mysql.proc table is added twice to the list
of table to lock although the requirements on the current locking API
assumes differently.

No test case is submitted because of the nature of the crash which is 
currently difficult to reproduce in a deterministic way.

This is a backport from 5.1

The 'BEGIN/COMMIT/ROLLBACK' log event could be filtered out if the
database is not selected by --database option of mysqlbinlog command.
This can result in problem if there are some statements in the
transaction are not filtered out.

To fix the problem, mysqlbinlog will output 'BEGIN/ROLLBACK/COMMIT' 
in regardless of the database filtering rules.

The 'BEGIN/COMMIT/ROLLBACK' log event could be filtered out if the
database is not selected by --database option of mysqlbinlog command.
This can result in problem if there are some statements in the
transaction are not filtered out.

To fix the problem, mysqlbinlog will output 'BEGIN/ROLLBACK/COMMIT' 
in regardless of the database filtering rules.

Backport from 6.0 to 5.1.
Only those sync points are included, which are used in debug_sync.test.

  The Debug Sync Facility allows to place synchronization points
  in the code:
  
  open_tables(...)
  
  DEBUG_SYNC(thd, "after_open_tables");
  
  lock_tables(...)
  
  When activated, a sync point can
  
  - Send a signal and/or
  - Wait for a signal
  
  Nomenclature:
  
  - signal:            A value of a global variable that persists
                       until overwritten by a new signal. The global
                       variable can also be seen as a "signal post"
                       or "flag mast". Then the signal is what is
                       attached to the "signal post" or "flag mast".
  
  - send a signal:     Assign the value (the signal) to the global
                       variable ("set a flag") and broadcast a
                       global condition to wake those waiting for
                       a signal.
  
  - wait for a signal: Loop over waiting for the global condition until
                       the global value matches the wait-for signal.
  
  Please find more information in the top comment in debug_sync.cc
  or in the worklog entry.

          replication
              
MySQL server uses wrong lock type (always TL_READ instead of
TL_READ_NO_INSERT when appropriate) for tables used in
subqueries of UPDATE statement. This leads in some cases to
a broken replication as statements are written in the wrong
order to the binlog.

can be interpreted as a shell metacharacter in some circumstances.
For example, it is interpreted as a command separator when invoking
a debugger.

The problem was that appending values to the end of an existing
ENUM or SET column was being treated as table data modification,
preventing a immediately (fast) table alteration that occurs when
only table metadata is being modified.

The cause was twofold: adding a enumeration or set members to the 
end of the list of valid member values was not being considered
a "compatible" table alteration, and for SET columns, the check
was being done upon the max display length and not the underlying
(pack) length of the field.

The solution is to augment the function that checks wether two ENUM
or SET fields are compatible -- by comparing the pack lengths and
performing a limited comparison of the member values.