The problem is that MySQL's 'fast' mutex implementation uses the
random() routine to determine the spin delay. Unfortunately, the
routine interface is not thead-safe and some implementations (eg:
glibc) might use a internal lock to protect the RNG state, causing
excessive locking contention if lots of threads are spinning on
a MySQL's 'fast' mutex. The code was also misusing the value
of the RAND_MAX macro, this macro represents the largest value
that can be returned from the rand() function, not random().

The solution is to use the quite simple Park-Miller random number
generator. The initial seed is set to 1 because the previously used
generator wasn't being seeded -- the initial seed is 1 if srandom()
is not called.

Futhermore, the 'fast' mutex implementation has several shortcomings
and provides no measurable performance benefit. Therefore, its use is
not recommended unless it provides directly measurable results.

Select with a "NULL NOT IN" condition containing complex
subselect from the same table as in the outer select failed
with an assertion.


The failure was caused by a concatenation of circumstances:
1) an inner select was optimized by make_join_statistics to use
   the QUICK_RANGE_SELECT access method (that implies an index
   scan of the table);
2) a subselect was independent (constant) from the outer select;
3) a condition was pushed down into inner select.

During the evaluation of a constant IN expression an optimizer
temporary changed the access method from index scan to table
scan, but an engine handler was already initialized for index
access by make_join_statistics. That caused an assertion.


Unnecessary index initialization has been removed from
the QUICK_RANGE_SELECT::init method (QUICK_RANGE_SELECT::reset
reinvokes this initialization).

            with COALESCE and JOIN

The server returned to a client the VARBINARY column type
instead of the DATE type for a result of the COALESCE,
IFNULL, IF, CASE, GREATEST or LEAST functions if that result
was filesorted in an anonymous temporary table during
the query execution.

For example:
  SELECT COALESCE(t1.date1, t2.date2) AS result
    FROM t1 JOIN t2 ON t1.id = t2.id ORDER BY result;


To create a column of various date/time types in a
temporary table the create_tmp_field_from_item() function
uses the Item::tmp_table_field_from_field_type() method
call. However, fields of the MYSQL_TYPE_NEWDATE type were
missed there, and the VARBINARY columns were created
by default.
Necessary condition has been added.

 - fixed an unitialized memory read
 - fixed a compilation warning
 - added a suppression for FC9 x86_64

           derived table cause crash

When a multi-UPDATE command fails to lock some table, and
subsequently succeeds, the tables need to be reopened if
they were altered. But the reopening procedure failed for
derived tables.

Extra cleanup has been added.

 Fixed the handling of system variable retrieval
in prepared statements : added a cleanup method
that clears up the cache and restores the 
original scope of the variable (which is overwritten
at fix_fields()).

TRIGGERS.SQL_MODE, EVENTS.SQL_MODE, TRIGGERS.DEFINER:
field type is changed to VARCHAR.

The problem was that PACK_KEYS and MAX_ROWS clause in ALTER TABLE did not trigger
table reconstruction.
The fix is to rebuild a table if PACK_KEYS or MAX_ROWS are specified.

Fixed a compilation warning

Hide "Table doesn't exist" errors if the table belongs to a merge table.

The problem: table_open_method is not calculated properly if '*' is used in 'select'
The fix: added table_open_method calculation for such case

upgrade from <=5.0.46 to >=5.0.48

Problem: 'check table .. for upgrade' doesn't detect 
incompatible collation changes made in 5.0.48.

Fix: check for incompatible collation changes.

                  
The code to get read the value of a system variable was extracting its value 
on PREPARE stage and was substituting the value (as a constant) into the parse tree.
Note that this must be a reversible transformation, i.e. it must be reversed before
each re-execution.
Unfortunately this cannot be reliably done using the current code, because there are
other non-reversible source tree transformations that can interfere with this
reversible transformation.
Fixed by not resolving the value at PREPARE, but at EXECUTE (as the rest of the 
functions operate). Added a cache of the value (so that it's constant throughout
the execution of the query). Note that the cache also caches NULL values.
Updated an obsolete related test suite (variables-big) and the code to test the 
result type of system variables (as per bug 74).

The failure was caused by executing a CREATE-SELECT statement that creates a
table in another database than the current one. In row-based logging, the
CREATE statement was written to the binary log without the database, hence
creating the table in the wrong database, causing the following inserts to
fail since the table didn't exist in the given database.

Fixed the bug by adding a parameter to store_create_info() that will make
the function print the database name before the table name and used that
in the calls that write the CREATE statement to the binary log. The database
name is only printed if it is different than the currently selected database.

The output of SHOW CREATE TABLE has not changed and is still printed without
the database name.

disabled a randomly failing test and opened a bug report

InnoDB Plugin locks table

This is a pre fix update that does the change to the handler api.

This is done since there are already changes in this version,
so the real fix does not need to change the api.