This is a performance issue for queries with subqueries evaluation
of which requires filesort.
Allocation of memory for the sort buffer at each evaluation of a
subquery may take a significant amount of time if the buffer is rather big.
With the fix we allocate the buffer at the first evaluation of the
subquery and reuse it at each subsequent evaluation.

into  rurik.mysql.com:/home/igor/mysql-5.0-opt

into  rurik.mysql.com:/home/igor/dev-opt/mysql-5.0-opt-bug19579

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            list using a function
When executing dependent subqueries they are re-inited and re-exec() for 
each row of the outer context.
The cause for the bug is that during subquery reinitialization/re-execution,
the optimizer reallocates JOIN::join_tab, JOIN::table in make_simple_join()
and the local variable in 'sortorder' in create_sort_index(), which is
allocated by make_unireg_sortorder().
Care must be taken not to allocate anything into the thread's memory pool
while re-initializing query plan structures between subquery re-executions.
All such items mush be cached and reused because the thread's memory pool
is freed at the end of the whole query.
Note that they must be cached and reused even for queries that are not 
otherwise cacheable because otherwise it will grow the thread's memory 
pool every time a cacheable query is re-executed. 
We provide additional members to the JOIN structure to store references 
to the items that need to be cached.

into  macbook.gmz:/Users/kgeorge/mysql/work/B22367-5.0-opt-merge

account predicates that become sargable after reading const tables.
In some cases this resulted in choosing non-optimal execution plans.
Now info of such potentially saragable predicates is saved in
an array and after reading const tables we check whether this
predicates has become saragable.

into  rakia.(none):/home/kgeorge/mysql/autopush/B22342-5.0-opt

 When using index for group by and range access the server isolates    
 a set of ranges based on the conditions over the key parts of the
 index used. Then it uses only the ranges over the GROUP BY fields to
 jump from one group to another. Since the GROUP BY fields may form a
 prefix over the index, we may use only a prefix of the ranges produced
 by the range optimizer.
 Each range contains a notion on whether it includes its border values.
 The problem is that when using a range prefix, the last range is open
 because it assumes that there is a range on the next keypart. Thus when
 we use a prefix range as it is, it excludes all border values.
 The solution is when ignoring the suffix of the range conditions 
 (to jump over the GROUP BY prefix only) the server must change the 
 remaining intervals so they always contain their borders, e.g. 
 if the whole range was :
 (1,-inf) <= (<group_by_col>,<min_max_arg_col>) < (1, 3) we must make
 (1) <= (<group_by_col>) <= (1) because (a,b) < (c1,c2) means :
 a < c1 OR (a = c1 AND b < c2).

             strings
MySQL is setting the flag HA_END_SPACE_KEYS for all the keys that reference
text or varchar columns with collation different than binary.
This was done to handle correctly the situation where a lookup on such a key
may return more than 1 row because of the presence of many rows that differ
only by the amount of trailing space in the table's string column.
Inserting such values however appears to violate the unique checks on 
INSERT/UPDATE. Thus that flag must not be set as it will prevent the optimizer
from choosing a faster access method.
This fix removes the setting of the HA_END_SPACE_KEYS flag.

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into  macbook.gmz:/Users/kgeorge/mysql/work/B14019-5.0-opt

   When resolving unqualified name references MySQL was not
   checking what is the item type for the reference. Thus
   e.g a string literal item that has by convention a name
   equal to its string value will also work as a reference to 
   a SELECT list item or a table field.
   Fixed by allowing only Item_ref or Item_field to referenced by
   (unqualified) name.

The mysql_alter_table() was able to rename only a table.

The view/table renaming code is moved from the function rename_tables 
to the new function called do_rename().
The mysql_alter_table() function calls it when it needs to rename a view.

The Cached_item_decimal::cmp() method wasn't checking for null pointer
returned from the val_decimal() of the item being cached.
This leads to server crash.

The Cached_item_decimal::cmp() method now check for null values.

into  macbook.local:/Users/kgeorge/mysql/work/B22781-5.0-opt

 Currently SQL_BIG_RESULT is checked only at compile time.
 However, additional optimizations may take place after
 this check that change the sort method from 'filesort'
 to sorting via index. As a result the actual plan
 executed is not the one specified by the SQL_BIG_RESULT
 hint. Similarly, there is no such test when executing
 EXPLAIN, resulting in incorrect output.
 The patch corrects the problem by testing for
 SQL_BIG_RESULT both during the explain and execution
 phases.

into  mysql.com:/home/hf/work/16813/my50-16813

into  mysql.com:/home/hf/work/16813/my50-16813

into  mysql.com:/home/hf/work/21888/my50-21888

into  rurik.mysql.com:/home/igor/mysql-5.0-opt

into  moonbone.local:/work/20503-bug-5.0-mysql

into  rurik.mysql.com:/home/igor/dev-opt/mysql-5.0-opt-bug22753

After the patch for big 21698 equality propagation stopped
working for BETWEEN and IN predicates with STRING arguments.
This changeset completes the solution of the above patch.

into  mysql.com:/home/hf/work/21888/my50-21888

RTree keys are really different from BTree and need specific
paramters to be set by optimizer to work.
Sometimes optimizer doesn't set those properly.
Here we decided just to add code to check that the parameters
are correct. Hope to fix optimizer sometimes.

We use the condition from CHECK OPTION twice handling UPDATE command.
First we construnct 'update_cond' AND 'option_cond'
condition to select records to be updated, then we check the
'option_cond' for the updated row.
The problem is that first 'AND' condition is optimized during the 'select'
which can break 'option_cond' structure, so it will be unusable for
the sectond use - to check the updated row.
Possible soultion is either use copy of the condition in the first
use or to make optimization less traumatic for the operands.
I picked the first one. 

  After merge fix

into  moonbone.local:/work/5505-bug-5.0-opt-mysql

On an INSERT into an updatable but non-insertable view an error message was
issued stating the view being not updatable. This can lead to a confusion of a
user.

A new error message is introduced. Is is showed when a user tries to insert
into a non-insertable view.

while space allocation

Under some circumstances DISTINCT clause can be converted to grouping.
In such cases grouping is performed by all items in the select list.
If an ORDER clause is present then items from it is prepended to group list.
But the case with ORDER wasn't taken into account when allocating the
array for sum functions. This leads to memory corruption and crash.

The JOIN::alloc_func_list() function now allocates additional space if there
is an ORDER by clause is specified and DISTINCT -> GROUP BY optimization is
possible.

into  dl145s.mysql.com:/data/bk/team_tree_merge/MERGE/mysql-5.0-opt

into  dl145s.mysql.com:/data/bk/team_tree_merge/MERGE/mysql-5.0-opt

into  dl145s.mysql.com:/data/bk/team_tree_merge/MERGE/mysql-4.1-opt

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