Backport from mysql-next-mr (5.6) to mysql-trunk (5.5)

Backport from mysql-next-mr (5.6) to mysql-trunk (5.5)

Backport from mysql-next-mr (5.6) to mysql-trunk (5.5)

Backport from mysql-next-mr (5.6) to mysql-trunk (5.5)

Backport from mysql-next-mr (5.6) to mysql-trunk (5.5)

Backport from mysql-next-mr (5.6) to mysql-trunk (5.5)

Backporting the fix from myql-next-mr (5.6) to mysql-trunk (5.5)

This fix is for cleanup, to resolve a remaining code review item.
Backport from mysql-next-mr (5.6) to mysql-trunk (5.5).

Fixed minor merge issues with #includes

Remove OS/2 specific code.

Remove QNX specific code.

Remove VMS specific code.

Remove Zortech specific code.

Remove MS-DOS specific code.

Remove Netware specific code.

Fixed style according to the specific innodb style, for innodb code.

Symptom:
When the sql function SLEEP() was executed in the slave SQL thread or from an event (as in
CREATE EVENT, not binlog event), then the timeout was capped to 5 seconds.

Background:
This bug was introduced in the fix of BUG#10374, in the function interruptible_wait() in
item_func.cc.
The function interruptible_wait(), called from item_func_sleep::val_int(), splits the
sleep into 5 seconds units. After each unit, it checks if thd->is_connected() is true: if
not, it stops sleeping. The purpose is to not use system resources to sleep when a client
disconnects.
However, thd->is_connected() returns false for the slave SQL thread and for the event
worker thread, because they don't connect to the server the same way as client threads
do.

Fix:
Make thd->is_connected() return true for all system threads.


sql/sql_class.h:
  Made THD::is_connected() return true for all system threads.

naming scheme for tests related to functions, rename analyse.test to
func_analyse.test (test for the ANALYSE() procedure). Avoids confusion
with the ANALYZE statement (tested in analyze.test).

analyse.test to func_analyse.test. Avoids confusion with the ANALYZE
statement.

This change is for performance optimization.

Fixed the performance schema instrumentation interface as follows:
- simplified mysql_unlock_mutex()
- simplified mysql_unlock_rwlock()
- simplified mysql_cond_signal()
- simplified mysql_cond_broadcast()

Changed the get_thread_XXX_locker apis to have one extra parameter,
to provide memory to the instrumentation implementation.
This API change allows to use memory provided by the caller,
to avoid having to use thread local storage.
Using this extra parameter will be done in a separate fix,
this change is for the interface only.

Adjusted all the code and unit tests accordingly.

Merged on behalf of Davi.

Post-merge fix: remove reference to file that is now gone.

Problem: Item_str_ascii_func::val_str() did not set
charset of the returned value properly.
  
  mysql-test/include/ctype_numconv.inc
  mysql-test/r/ctype_binary.result
  mysql-test/r/ctype_cp1251.result
  mysql-test/r/ctype_latin1.result
  mysql-test/r/ctype_ucs.result
  - Adding tests
  
  sql/item_strfunc.cc
  - Adding initialization of charset

Post-merge fix: cast argument and correct type in assignment.

      
The server was not cleaning up some dbug allocated memory 
before exiting. This is not a real problem, as this memory 
would be deallocated anyway. Nonetheless, we improve the 
mysqlbinlog exit procedure, wrt to memory book-keeping, when 
no parameter is given.
      
To fix this, we deploy a call to my_end() before the
thread exits.

Essentially, the problem is that safemalloc is excruciatingly
slow as it checks all allocated blocks for overrun at each
memory management primitive, yielding a almost exponential
slowdown for the memory management functions (malloc, realloc,
free). The overrun check basically consists of verifying some
bytes of a block for certain magic keys, which catches some
simple forms of overrun. Another minor problem is violation
of aliasing rules and that its own internal list of blocks
is prone to corruption.

Another issue with safemalloc is rather the maintenance cost
as the tool has a significant impact on the server code.
Given the magnitude of memory debuggers available nowadays,
especially those that are provided with the platform malloc
implementation, maintenance of a in-house and largely obsolete
memory debugger becomes a burden that is not worth the effort
due to its slowness and lack of support for detecting more
common forms of heap corruption.

Since there are third-party tools that can provide the same
functionality at a lower or comparable performance cost, the
solution is to simply remove safemalloc. Third-party tools
can provide the same functionality at a lower or comparable
performance cost. 

The removal of safemalloc also allows a simplification of the
malloc wrappers, removing quite a bit of kludge: redefinition
of my_malloc, my_free and the removal of the unused second
argument of my_free. Since free() always check whether the
supplied pointer is null, redudant checks are also removed.

Also, this patch adds unit testing for my_malloc and moves
my_realloc implementation into the same file as the other
memory allocation primitives.

client/mysqldump.c:
  Pass my_free directly as its signature is compatible with the
  callback type -- which wasn't the case for free_table_ent.

from mysql-next-mr-opt-backporting.

Bug#54515: Crash in opt_range.cc::get_best_group_min_max on 
           SELECT from VIEW with GROUP BY
      
When handling the grouping items in get_best_group_min_max, the
items need to be of type Item_field. In this bug, an ASSERT 
triggered because the item used for grouping was an 
Item_direct_view_ref (i.e., the group column is from a view). 
The fix is to get the real_item since Item_ref* pointing to 
Item_field is ok.

mysql-test/r/select.result:
  Add test for BUG#54515
mysql-test/t/select.test:
  Add test for BUG#54515
sql/opt_range.cc:
  Get the real_item() when processing grouping items in 
  get_best_group_min_max.

from next-mr-bugfixing:
BUG#54682 "set sql_select_limit=0 does not work"; let SQL_SELECT_LIMIT=0
work like it does in 5.1.


mysql-test/suite/sys_vars/r/sql_select_limit_func.result:
  before the fix, the SET would emit a warning (0 being rounded up to 1)
  and SELECTs would return one row.
sql/sys_vars.cc:
  0 is allowed, it means an implicit LIMIT 0 (i.e. no rows returned)

Problem: sha2() reported its result as BINARY

Fix:
- Inheriting Item_func_sha2 from Item_str_ascii_func
- Setting max_length via fix_length_and_charset() 
  instead of direct assignment.
- Adding tests