into  magare.gmz:/home/kgeorge/mysql/autopush/B26186-5.0-opt

Patch appled after doing a pull from the team tree. Additional tests had to be
fixed

into  linux-st28.site:/home/martin/mysql/src/5.0o-bug24791

into  linux-st28.site:/home/martin/mysql/src/5.0o-bug24791

The problem in this bug is when we create temporary tables. When
temporary tables are created for unions, there is some 
inferrence being carried out regarding the type of the column.
Whenever this column type is inferred to be REAL (i.e. FLOAT or
DOUBLE), MySQL will always try to maintain exact precision, and
if that is not possible (there are hardware limits, since FLOAT
and DOUBLE are stored as approximate values) will switch to
using approximate values. The problem here is that at this point
the information about number of significant digits is not 
available. Furthermore, the number of significant digits should
be increased for the AVG function, however, this was not properly 
handled. There are 4 parts to the problem:

#1: DOUBLE and FLOAT fields don't display their proper display 
lengths in max_display_length(). This is hard-coded as 53 for 
DOUBLE and 24 for FLOAT. Now changed to instead return the 
field_length.

#2: Type holders for temporary tables do not preserve the 
max_length of the Item's from which they are created, and is 
instead reverted to the 53 and 24 from above. This causes 
*all* fields to get non-fixed significant digits.

#3: AVG function does not update max_length (display length)
when updating number of decimals.

#4: The function that switches to non-fixed number of 
significant digits should use DBL_DIG + 2 or FLT_DIG + 2 as 
cut-off values (Since fixed precision does not use the 'e' 
notation)

Of these points, #1 is the controversial one, but this 
change is preferred and has been cleared with Monty. The 
function causes quite a few unit tests to blow up and they had
to b changed, but each one is annotated and motivated. We 
frequently see the magical 53 and 24 give way to more relevant
numbers.

  fix for cast( AS DATETIME)+0 in 5.0 and above versions.
  val_real now works using val_decimal for DATETIME Items
  Superfluous val_real() methods deleted

into  mysql.com:/home/hf/work/mrg/mysql-5.0-opt

  fix for cast( AS DATETIME) + 0 operation.
  I just implemented Item_datetime_typecast::val() method
  as it is usually done in other classes.
  Should be fixed more radically in 5.0

into  mysql.com:/home/hf/work/mrg/mysql-5.0-opt

into  mysql.com:/home/hf/work/mrg/mysql-5.0-opt

into  mysql.com:/home/hf/work/mrg/mysql-5.0-opt

into  mysql.com:/home/hf/work/mrg/mysql-4.1-opt

into  mysql.com:/home/hf/work/25492/my50-25492

of its argument happened to be a decimal expression returning
the NULL value.
The crash was due to the fact the function in_decimal::set did
not take into account that val_decimal() could return 0 if 
the decimal expression had been evaluated to NULL.  

into  bodhi.local:/opt/local/work/mysql-5.0-runtime

into  moonbone.local:/mnt/gentoo64/work/23345-bug-5.0-opt-mysql

INTO clause can be specified only for the last select of a UNION and it
receives the result of the whole query. But it was wrongly allowed in
non-last selects of a UNION which leads to a confusing query result.

Now INTO allowed only in the last select of a UNION.

into  olga.mysql.com:/home/igor/dev-opt/mysql-5.0-opt-bug27257

aggregated in outer context returned wrong results.
This happened only if the subquery did not contain any references
to outer fields.
As there were no references to outer fields the subquery erroneously
was taken for non-correlated one.
Now any set function aggregated in outer context makes the subquery
correlated.

into  magare.gmz:/home/kgeorge/mysql/autopush/B24484-5.0

To correctly decide which predicates can be evaluated with a given table
the optimizer must know the exact set of tables that a predicate depends 
on. If that mask is too wide (refer to non-existing tables) the optimizer
can erroneously skip a predicate.
One such case of wrong table usage mask were the aggregate functions.
The have a all-1 mask (meaning depend on all tables, including non-existent
ones).
Fixed by making a real used_tables mask for the aggregates. The mask is
constructed in the following way :
1. OR the table dependency masks of all the arguments of the aggregate.
2. If all the arguments of the function are from the local name resolution 
  context and it is evaluated in the same name resolution
  context where it is referenced all the tables from that name resolution 
  context are OR-ed to the dependency mask. This is to denote that an
  aggregate function depends on the number of rows it processes.
3. Handle correctly the case of an aggregate function optimization (such that
  the aggregate function can be pre-calculated and made a constant).

Made sure that an aggregate function is never a constant (unless subject of a 
specific optimization and pre-calculation).  

One other flaw was revealed and fixed in the process : references were 
not calling the recalculation method for used_tables of their targets.

  Removed wrong fix for the bug#27006.
  The bug was added by the fix for the bug#19978 and fixed by Monty on 2007/02/21.
trigger.test, trigger.result:
  Corrected test case for the bug#27006.

into  bodhi.local:/opt/local/work/mysql-5.0-runtime

UPDATE if the row wasn't actually changed.

This bug was caused by fix for bug#19978. It causes AFTER UPDATE triggers
not firing if a row wasn't actually changed by the update part of the
INSERT .. ON DUPLICATE KEY UPDATE.

Now triggers are always fired if a row is touched by the INSERT ... ON
DUPLICATE KEY UPDATE.

into  magare.gmz:/home/kgeorge/mysql/autopush/B26261-5.0-opt

 INSERT uses query_id to verify what fields are
 mentioned in the fields list of the INSERT command.
 However the check for that is made after the 
 ON DUPLICATE KEY is processed. This causes all
 the fields mentioned in ON DUPLICATE KEY to be 
 considered as mentioned in the fields list of 
 INSERT.
 Moved the check up, right after processing the
 fields list.

into  mysql.com:/home/gluh/MySQL/Merge/5.0-opt

The crash happens when 'skip-grant-tables' is enabled.
We skip the filling of I_S privilege tables 
if acl_cache is not initialized.

into  mysql.com:/home/hf/work/mrg/mysql-5.0-opt

into  mysql.com:/home/hf/work/mrg/mysql-5.0-opt

into  mysql.com:/home/svoj/devel/bk/mysql-5.0-engines

into  moonbone.local:/mnt/gentoo64/work/27033-bug-5.0-opt-mysql

touched but not actually changed.

The LAST_INSERT_ID() is reset to 0 if no rows were inserted or changed.
This is the case when an INSERT ... ON DUPLICATE KEY UPDATE updates a row
with the same values as the row contains.

Now the LAST_INSERT_ID() values is reset to 0 only if there were no rows
successfully inserted or touched.
The new 'touched' field is added to the COPY_INFO structure. It holds the
number of rows that were touched no matter whether they were actually
changed or not.

into  mysql.com:/home/hf/work/mrg/mysql-5.0-opt

into  mysql.com:/home/hf/work/mrg/mysql-5.0-opt

into  mockturtle.local:/home/dlenev/src/mysql-4.1-merge

into  mockturtle.local:/home/dlenev/src/mysql-5.0-merge

into  mockturtle.local:/home/dlenev/src/mysql-5.0-bg25966-2

TABLE ... WRITE".

Memory and CPU hogging occured when connection which had to wait for table
lock was serviced by thread which previously serviced connection that was
killed (note that connections can reuse threads if thread cache is enabled).
One possible scenario which exposed this problem was when thread which
provided binlog dump to replication slave was implicitly/automatically
killed when the same slave reconnected and started pulling data through
different thread/connection.
The problem also occured when one killed particular query in connection
(using KILL QUERY) and later this connection had to wait for some table
lock.

This problem was caused by the fact that thread-specific mysys_var::abort
variable, which indicates that waiting operations on mysys layer should
be aborted (this includes waiting for table locks), was set by kill
operation but was never reset back. So this value was "inherited" by the
following statements or even other connections (which reused the same
physical thread). Such discrepancy between this variable and THD::killed
flag broke logic on SQL-layer and caused CPU and memory hogging.

This patch tries to fix this problem by properly resetting this member.

There is no test-case associated with this patch since it is hard to test
for memory/CPU hogging conditions in our test-suite.