DOWNGRADED FROM 5.6.11 TO 5.6.10

Problem was new syntax not accepted by previous version.

Fixed by adding version comment of /*!50531 around the
new syntax.

Like this in the .frm file:
'PARTITION BY KEY /*!50611 ALGORITHM = 2 */ () PARTITIONS 3'
and also changing the output from SHOW CREATE TABLE to:
CREATE TABLE t1 (a INT)
/*!50100 PARTITION BY KEY */ /*!50611 ALGORITHM = 1 */ /*!50100 ()
PARTITIONS 3 */

It will always add the ALGORITHM into the .frm for KEY [sub]partitioned
tables, but for SHOW CREATE TABLE it will only add it in case it is the non
default ALGORITHM = 1.

Also notice that for 5.5, it will say /*!50531 instead of /*!50611, which
will make upgrade from 5.5 > 5.5.31 to 5.6 < 5.6.11 fail!
If one downgrades an fixed version to the same major version (5.5 or 5.6) the
bug 14521864 will be visible again, but unless the .frm is updated, it will
work again when upgrading again.

Also fixed so that the .frm does not get updated version
if a single partition check passes.

For the error code ER_TOO_LONG_IDENT, the identifier is expected in the my_error call.  So removing this line from here.  

FROM SHOW CREATE

Problem: The length of the internally generated foreign key name 
is not checked. 

Solution: The length of the internally generated foreign key name is
checked.  If it is greater than the allowed limit, an error message
is reported. Also, the constraint name is printed in the same manner
as the table name, using the system charset information.

rb://1969 approved by Marko.

Reverting back the previous changes as they are causing
issues in PB2.

Problem: Sys_vars suite is disabled in mysql-5.1 branch.
Fix: To enable sys_vars suite in mysql-5.1, add it in
mysql-test-run.pl file and also sys_vars suite should be
added to Makefile.am inorder to get that test directory

will not export internal symbols.

srv_export_innodb_status(): Read the purge_sys fields while holding
purge_sys->latch.

Approved by Sunny Bains

             5.1 SERVER

Problem was caused by the COM_CHANGE_USER parsing code. That code ignored
character set number passed in COM_CHANGE_USER packet. Instead
character_set_client values was used. User name was not converted at all.

Fixed by using passed character set number to convert both db and user names.
If COM_CHANGE_USER does not contain character set number then
character_set_client is used to convert both names.

This is a backport of the fix for:

Bug#13633549 HANDLE_FATAL_SIGNAL IN TEST_IF_SKIP_SORT_ORDER/CREATE_SORT_INDEX
Don't invoke the range optimizer for a NULL select.

SUITE FOR 5.1

SYS_VARS suite is not enabled in MTR by default
run. Enabling it with this check-in.

mysql-test/suite/sys_vars/t/disabled.def:
  Till the bugs are fixed, disabling the failed test scripts

Null merge from mysql-5.1

Null merge from mysql-5.1

Null-Merge from mysql-5.5

               DEREFERENCING UT_DBG_NULL_PTR
The abort() call is standard C but InnoDB only uses it in GCC
environments.  UT_DBG_USE_ABORT is not defined the code crashed
by dereferencing a null pointer instead of calling abort().
Other code throughout MySQL including ndb, sql, mysys and other
places call abort() directly.

This bug also affects innodb.innodb_bug14147491.test which fails
randomly on windows because of this issue. 

Approved by marko in http://rb.no.oracle.com/rb/r/1936/

Currently MySQL MSI installer on Windows installs MySQL in 
"per user" mode. It means that if a Windows machine has 
multiple users, they each can install MySQL independently. 
However the default path of MySQL is "C:\Program Files (x86)\MySQL\"
and when two users install MySQL on same machine, the installation
by second user just overwrites the MySQL files. This default shared 
location leads to the issue where if the second user uninstalls MySQL,
the installation files are removed for the first user as well.

In this fix, we are now making the default installation "per machine".
It means that when MySQL is installed with defaults options, all
users can see the shortcuts for MySQL in start menu(since installations 
is for all users). Also when any user relaunches the installer, it will 
consider that action uninstallation rather than installation for that user.

There are command line options in installer that can be used to undo the
"per machine" installation but will not consider that scenario.MySQL 
is a server product and it does not make a lot of sense to install it
differently for each user.

PROBLEM:
When large number of connections are continuously made
with wait_timeout of 600 seconds for  some hours, some
connections remain after wait_timeout expired and also
new connections get struck under the configuration and
the scenario reported in bug#16196591.
FIX:
The cause of this bug is the issue identified  and fixed in
the BUG#16088658 in 5.6.Also LOCK_thread_count contention 
issue fixed in BUG#15921866 in 5.6 need to be in 5.5 as 
well. Since the issue is not reproducible, it has been
verified at customer configuration the issue could not
be reproduced after a 48-hour test with a non-debug build               
which includes the above two fixes backported.

I/O IS ASYNC

rb://1934
approved by: Mikael Ronstrom (over email)
    
When submitting AIO read request don't signal that the thread is
about to wait on DISKIO

Analysis:
--------

As part of the fix for Bug#11757464, the 'out of memory' error
condition was not pushed to the diagnostic area as it requires
memory allocation. However in cases of SIGNAL/RESIGNAL 'out of
memory' error, the server may not be out of memory. Hence it
would be good to report the error in such cases.

Fix:
---

Push only non fatal 'out of memory' errors to the diagnostic area.
Since SIGNAL/RESIGNAL of 'out of memory' error may not be fatal,
the error is reported.

Manual up-merge from 5.1 to 5.5.

Some queries with the "SELECT ... FROM DUAL" nested subqueries
failed with an assertion on debug builds.
Non-debug builds were not affected.

There were a few different issues with similar assertion
failures on different queries:

1. The first problem was related to the incomplete propagation
of the "non-constant" item status from underlying subquery
items to the outer item tree: in some cases non-constants were
interpreted as constants and evaluated at the preparation stage
(val_int() calls withing fix_fields() etc).

Thus, the default implementation of Item_ref::const_item() from
the Item parent class didn't take into account the "const_item"
status of the referenced item tree -- it used the insufficient
"used_tables() == 0" check instead. This worked in most cases
since our "non-constant" functions like RAND() and SLEEP() set
the RAND_TABLE_BIT in the used table map, so they aren't
non-constant from Item_ref's "point of view". However, the
"SELECT ... FROM DUAL" subquery may have an empty map of used
tables, but at the same time subqueries are never "constant" at
the context analysis stage (preparation, view creation etc).
So, the non-contantness of such subqueries was missed.

Fix: the Item_ref::const_item() function has been overloaded to
take into account both (*ref)->const_item() status and tricky
Item_ref::used_tables() return values, since the only
(*ref)->const_item() call is not enough there.

2. In some cases instead of the const_item() call we check a
value of the Item::with_subselect field to recognize items
with nested subqueries. However, the Item_ref class didn't
propagate this value from the referenced item tree.

Fix: Item::has_subquery() and Item_ref::has_subquery()
functions have been backported from 5.6. All direct
references to the with_subselect fields of nested items have
been replaced with the has_subquery() function call.

3. The Item_func_regex class didn't propagate with_subselect
as well, since it overloads the Item_func::fix_fields()
function with insufficient fix_fields() implementation.

Fix: the Item_func_regex::fix_fields() function has been
modified to gather "constant" statuses from inner items.

4. The Item_func_isnull::update_used_tables() function has
a special branch for the underlying item where the maybe_null
value is false: in this case it marks the Item_func_isnull
as a "const_item" and sets the cached_value to false.
However, the Item_func_isnull::val_int() was not in sync with
update_used_tables(): it didn't take into account neither
const_item_cache nor cached_value for the case of
"args[0]->maybe_null == false optimization".
As far as such an Item_func_isnull has "const_item() == true",
it's ok to call Item_func_isnull::val_int() etc from outer
items on preparation stage. In this case the server tried to
call Item_func_isnull::args[0]->isnull(), and if the args[0]
item contained a nested not-nullable subquery, it failed
with an assertion.

Fix: take the value of Item_func_isnull::const_item_cache into
account in the val_int() function.

5. The auxiliary Item_is_not_null_test class has a similar
optimization in the update_used_tables() function as the
Item_func_isnull class has, and the same issue in the val_int()
function.
In addition to that the Item_is_not_null_test::update_used_tables()
doesn't update the const_item_cache value, so the "maybe_null"
optimization is useless there. Thus, we missed some optimizations
of cases like these (before and after the fix):
  <  <is_not_null_test>(a),
  ---
  >  <cache>(<is_not_null_test>(a)),
or
  < having (<is_not_null_test>(a) and <is_not_null_test>(a))
  ---
  > having 1
etc.

Fix: update Item_is_not_null_test::const_item_cache in
update_used_tables() and take in into account in val_int().

innodb_bug12400341.test is disabled for valgrind daily test.
It might be affected by the previous test's undo slots existing,
because of slower execution.

Backport of fix for Bug#13581962

mysql-test/r/cast.result:
  Added test result for Bug#13581962,Bug#14096619
mysql-test/r/ctype_utf8mb4.result:
  Added test result for Bug#13581962,Bug#14096619
mysql-test/t/cast.test:
  Added test case for Bug#13581962,Bug#14096619
mysql-test/t/ctype_utf8mb4.test:
  Added test case for Bug#13581962,Bug#14096619
sql/item_func.h:
  limit max length by MY_INT64_NUM_DECIMAL_DIGITS

Backport of Bug#13581962

mysql-test/r/cast.result:
  Added test result for Bug#13581962,Bug#14096619
mysql-test/t/cast.test:
  Added test case for Bug#13581962,Bug#14096619
sql/item_func.h:
  limit max length by MY_INT64_NUM_DECIMAL_DIGITS