GitLab

"Grantor" columns' data is lost when replicating mysql.tables_priv.
Slave SQL thread used its default user ''@'' as the grantor of GRANT|REVOKE
statements executing on it.

In this patch, current user is put in query log event for all GRANT and REVOKE
statement, SQL thread uses the user in query log event as grantor.


mysql-test/suite/rpl/r/rpl_do_grant.result:
  Add test for this bug.
mysql-test/suite/rpl/t/rpl_do_grant.test:
  Add test for this bug.
sql/log_event.cc:
  Refactoring THD::current_user_used and related functions.
  current_user_used is used to judge if current user should be
  binlogged in query log event. So it is better to call it m_binlog_invoker.
  The related functions are renamed too.
sql/sql_class.cc:
  Refactoring THD::current_user_used and related functions.
  current_user_used is used to judge if current user should be
  binlogged in query log event. So it is better to call it m_binlog_invoker.
  The related functions are renamed too.
sql/sql_class.h:
  Refactoring THD::current_user_used and related functions.
  current_user_used is used to judge if current user should be
  binlogged in query log event. So it is better to call it m_binlog_invoker.
  The related functions are renamed too.
sql/sql_parse.cc:
  Call binlog_invoker() for GRANT and REVOKE statements.

        'CREATE TABLE IF NOT EXISTS ... SELECT' behaviour
BUG#55474, BUG#55499, BUG#55598, BUG#55616 and BUG#55777 are fixed
in this patch too.

This is the 5.1 part.
It implements:
- if the table exists, binlog two events: CREATE TABLE IF NOT EXISTS
  and INSERT ... SELECT

- Insert nothing and binlog nothing on master if the existing object
  is a view. It only generates a warning that table already exists.


mysql-test/r/trigger.result:
  Ather this patch, 'CREATE TABLE IF NOT EXISTS ... SELECT' will not
  insert anything if the creating table already exists and is a view.
sql/sql_class.h:
  Declare virtual function write_to_binlog() for select_insert.
  It's used to binlog 'create select'
sql/sql_insert.cc:
  Implement write_to_binlog();
  Use write_to_binlog() instead of binlog_query() to binlog the statement.
  if the table exists, binlog two events: CREATE TABLE IF NOT EXISTS
  and INSERT ... SELECT
sql/sql_lex.h:
  Declare create_select_start_with_brace and create_select_pos.
  They are helpful for binlogging 'create select'
sql/sql_parse.cc:
  Do nothing on master if the existing object is a view.
sql/sql_yacc.yy:
  Record the relative postion of 'SELECT' in the 'CREATE ...SELECT' statement.
  Record whether there is a '(' before the 'SELECT' clause.

lock wait time. Including the InnoDB lock time in the exiting "Lock_time"
output.

                        
After BUG#36649, warnings for sub-statements are cleared when a 
new sub-statement is started. This is problematic since it suppresses
warnings for unsafe statements in some cases. It is important that we
always give a warning to the client, because the user needs to know
when there is a risk that the slave goes out of sync.
                        
We fixed the problem by generating warning messages for unsafe statements
while returning from a stored procedure, function, trigger or while
executing a top level statement.
                        
We also started checking unsafeness when both performance and log tables are
used. This is necessary after the performance schema which does a distinction
between performance and log tables.

mysql-test/extra/rpl_tests/create_recursive_construct.inc:
  Changed the order of the calls in the procedure because the code
  that checks if a warning message is printed out expects that the
  first statement gives an warning what is not the case for INSERT
  INTO ta$CRC_ARG_level VALUES (47);
mysql-test/suite/binlog/r/binlog_stm_unsafe_warning.result:
  Updated the result file.
mysql-test/suite/binlog/r/binlog_unsafe.result:
  There are several changes here:
          
  (1) - Changed the CREATE PROCEDURE $CRC.
                                  
  (2) - The procedure $CRC was failing and the content of the binlog
        was being printed out, after fix (1) the failure disappeared.
                                  
  (3) - The warning message for unsafeness due to auto-increment collumns was
        changed.
                                  
  (4) - The warning message for unsafeness due to VERSION(), RAND() was changed.
mysql-test/suite/binlog/t/binlog_stm_unsafe_warning.test:
  Tested filters.
mysql-test/suite/binlog/t/binlog_unsafe.test:
  Reenabled the test case binlog_unsafe.
mysql-test/suite/binlog/t/disabled.def:
  Reenabled the test case binlog_unsafe.
mysql-test/suite/rpl/r/rpl_begin_commit_rollback.result:
  Updated the result file.
mysql-test/suite/rpl/r/rpl_non_direct_stm_mixing_engines.result:
  Updated the result file.
mysql-test/suite/rpl/r/rpl_stm_auto_increment_bug33029.result:
  Updated the result file.
sql/sql_class.cc:
  Moved the stmt_accessed_table_flag variable and related information to the
  LEX as we need the variable reset after each statement even inside a stored
  procedure, what did not happen if the information was in the THD.
          
  Changed the routine in the THD::binlog_query that prints the warning
  messages to avoid trying to print them when inside a stored procedure,
  function or trigger.
                          
  Checked for unsafeness when both performance and log tables where used.
  After the introduction of the performance schema, we need to check both.

Merged the implementation to a new base tree.

******
This patch fixes the following bugs:
  - Bug#5889: Exit handler for a warning doesn't hide the warning in
    trigger
  - Bug#9857: Stored procedures: handler for sqlwarning ignored
  - Bug#23032: Handlers declared in a SP do not handle warnings generated
    in sub-SP
  - Bug#36185: Incorrect precedence for warning and exception handlers

The problem was in the way warnings/errors during stored routine execution
were handled. Prior to this patch the logic was as follows:

  - when a warning/an error happens: if we're executing a stored routine,
    and there is a handler for that warning/error, remember the handler,
    ignore the warning/error and continue execution.

  - after a stored routine instruction is executed: check for a remembered
    handler and activate one (if any).

This logic caused several problems:

  - if one instruction generates several warnings (errors) it's impossible
    to choose the right handler -- a handler for the first generated
    condition was chosen and remembered for activation.

  - mess with handling conditions in scopes different from the current one.

  - not putting generated warnings/errors into Warning Info (Diagnostic
    Area) is against The Standard.

The patch changes the logic as follows:

  - Diagnostic Area is cleared on the beginning of each statement that
    either is able to generate warnings, or is able to work with tables.

  - at the end of a stored routine instruction, Diagnostic Area is left
    intact.

  - Diagnostic Area is checked after each stored routine instruction. If
    an instruction generates several condition, it's now possible to take a
    look at all of them and determine an appropriate handler.

mysql-test/r/signal.result:
  Update result file:
    1. handled conditions are not cleared any more;
    2. reflect changes in signal.test
mysql-test/r/signal_demo3.result:
  Update result file: handled conditions are not cleared any more.
  Due to playing with max_error_count, resulting warning lists
  have changed.
mysql-test/r/sp-big.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/r/sp-bugs.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/r/sp-code.result:
  Update result file:
    1. handled conditions are not cleared any more.
    2. add result for a new test case in sp-code.test.
mysql-test/r/sp-error.result:
  Update result file:
    1. handled conditions are not cleared any more.
    2. add result for a new test case in sp-error.test.
mysql-test/r/sp.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/r/sp_trans.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/r/strict.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/r/view.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/suite/funcs_1/r/innodb_storedproc_02.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/suite/funcs_1/r/memory_storedproc_02.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/suite/funcs_1/r/myisam_storedproc_02.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/suite/funcs_1/r/storedproc.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/suite/rpl/r/rpl_row_sp005.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/suite/rpl/r/rpl_row_sp006_InnoDB.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/suite/rpl/r/rpl_row_trig003.result:
  Update result file: handled conditions are not cleared any more.
mysql-test/t/signal.test:
  Make a test case more readable in the result file.
mysql-test/t/sp-code.test:
  Add a test case for Bug#23032 checking that
  No Data takes precedence on Warning.
mysql-test/t/sp-error.test:
  Adding test cases for:
    - Bug#23032
    - Bug#36185
    - Bug#5889
    - Bug#9857
mysql-test/t/sp.test:
  Fixing test case to reflect behavioral changes made by the patch.
sql/sp_head.cc:
  Reset the per-statement warning count before executing
  a stored procedure instruction.
  
  Move to a separate function code which checks the
  completion status of the executed statement and searches
  for a handler.
  
  Remove redundant code now that search for a handler is
  done after execution, errors are always pushed.
sql/sp_pcontext.h:
  Remove unused code.
sql/sp_rcontext.cc:
  - Polish sp_rcontext::find_handler(): use sp_rcontext::m_hfound instead
    of an extra local variable;
  
  - Remove sp_rcontext::handle_condition();
  
  - Introduce sp_rcontext::activate_handler(), which prepares
    previously found handler for execution.
  
  - Move sp_rcontext::enter_handler() code into activate_handler(),
    because enter_handler() is used only from there;
  
  - Cleanups;
  
  - Introduce DBUG_EXECUTE_IF() for a test case in sp-code.test
sql/sp_rcontext.h:
  - Remove unused code
  - Cleanups
sql/sql_class.cc:
  Merge THD::raise_condition_no_handler() into THD::raise_condition().
  After the patch raise_condition_no_handler() was called
  in raise_condition() only.
sql/sql_class.h:
  Remove raise_condition_no_handler().
sql/sql_error.cc:
  Remove Warning_info::reserve_space() -- handled conditions are not
  cleared any more, so there is no need for RESIGNAL to re-push them.
sql/sql_error.h:
  Remove Warning_info::reserve_space().
sql/sql_signal.cc:
  Handled conditions are not cleared any more,
  so there is no need for RESIGNAL to re-push them.

to be more descriptive.

TABLES <list> WITH READ LOCK are incompatible".

The problem was that FLUSH TABLES <list> WITH READ LOCK
which was issued when other connection has acquired global
read lock using FLUSH TABLES WITH READ LOCK was blocked
and has to wait until global read lock is released.

This issue stemmed from the fact that FLUSH TABLES <list>
WITH READ LOCK implementation has acquired X metadata locks
on tables to be flushed. Since these locks required acquiring
of global IX lock this statement was incompatible with global
read lock.

This patch addresses problem by using SNW metadata type of
lock for tables to be flushed by FLUSH TABLES <list> WITH
READ LOCK. It is OK to acquire them without global IX lock
as long as we won't try to upgrade those locks. Since SNW
locks allow concurrent statements using same table FLUSH
TABLE <list> WITH READ LOCK now has to wait until old
versions of tables to be flushed go away after acquiring
metadata locks. Since such waiting can lead to deadlock
MDL deadlock detector was extended to take into account
waits for flush and resolve such deadlocks.

As a bonus code in open_tables() which was responsible for
waiting old versions of tables to go away was refactored.
Now when we encounter old version of table in open_table()
we don't back-off and wait for all old version to go away,
but instead wait for this particular table to be flushed.
Such approach supported by deadlock detection should reduce
number of scenarios in which FLUSH TABLES aborts concurrent
multi-statement transactions.

Note that active FLUSH TABLES <list> WITH READ LOCK still
blocks concurrent FLUSH TABLES WITH READ LOCK statement
as the former keeps tables open and thus prevents the
latter statement from doing flush.

mysql-test/include/handler.inc:
  Adjusted test case after changing status which is set
  when FLUSH TABLES waits for tables to be flushed from
  "Flushing tables" to "Waiting for table".
mysql-test/r/flush.result:
  Added test which checks that "flush tables <list> with
  read lock" is compatible with active "flush tables with
  read lock" but not vice-versa. This test also covers
  bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES
  <list> WITH READ LOCK are incompatible".
mysql-test/r/mdl_sync.result:
  Added scenarios in which wait for table to be flushed
  causes deadlocks to the coverage of MDL deadlock detector.
mysql-test/suite/perfschema/r/dml_setup_instruments.result:
  Adjusted test results after removal of COND_refresh
  condition variable.
mysql-test/suite/perfschema/r/server_init.result:
  Adjusted test and its results after removal of COND_refresh
  condition variable.
mysql-test/suite/perfschema/t/server_init.test:
  Adjusted test and its results after removal of COND_refresh
  condition variable.
mysql-test/t/flush.test:
  Added test which checks that "flush tables <list> with
  read lock" is compatible with active "flush tables with
  read lock" but not vice-versa. This test also covers
  bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES
  <list> WITH READ LOCK are incompatible".
mysql-test/t/kill.test:
  Adjusted test case after changing status which is set
  when FLUSH TABLES waits for tables to be flushed from
  "Flushing tables" to "Waiting for table".
mysql-test/t/lock_multi.test:
  Adjusted test case after changing status which is set
  when FLUSH TABLES waits for tables to be flushed from
  "Flushing tables" to "Waiting for table".
mysql-test/t/mdl_sync.test:
  Added scenarios in which wait for table to be flushed
  causes deadlocks to the coverage of MDL deadlock detector.
sql/ha_ndbcluster.cc:
  Adjusted code after adding one more parameter for
  close_cached_tables() call - timeout for waiting for
  table to be flushed.
sql/ha_ndbcluster_binlog.cc:
  Adjusted code after adding one more parameter for
  close_cached_tables() call - timeout for waiting for
  table to be flushed.
sql/lock.cc:
  Removed COND_refresh condition variable. See comment
  for sql_base.cc for details.
sql/mdl.cc:
  Now MDL deadlock detector takes into account information
  about waits for table flushes when searching for deadlock.
  To implement this change:
  - Declaration of enum_deadlock_weight and
    Deadlock_detection_visitor were moved to mdl.h header
    to make them available to the code in table.cc which
    implements deadlock detector traversal through edges
    of waiters graph representing waiting for flush.
  - Since now MDL_context may wait not only for metadata
    lock but also for table to be flushed an abstract
    Wait_for_edge class was introduced. Its descendants
    MDL_ticket and Flush_ticket incapsulate specifics
    of inspecting waiters graph when following through
    edge representing wait of particular type.
  
  We no longer require global IX metadata lock when acquiring
  SNW or SNRW locks. Such locks are needed only when metadata
  locks of these types are upgraded to X locks. This allows
  to use SNW locks in FLUSH TABLES <list> WITH READ LOCK
  implementation and keep the latter compatible with global
  read lock.
sql/mdl.h:
  Now MDL deadlock detector takes into account information
  about waits for table flushes when searching for deadlock.
  To implement this change:
  - Declaration of enum_deadlock_weight and
    Deadlock_detection_visitor were moved to mdl.h header
    to make them available to the code in table.cc which
    implements deadlock detector traversal through edges
    of waiters graph representing waiting for flush.
  - Since now MDL_context may wait not only for metadata
    lock but also for table to be flushed an abstract
    Wait_for_edge class was introduced. Its descendants
    MDL_ticket and Flush_ticket incapsulate specifics
    of inspecting waiters graph when following through
    edge representing wait of particular type.
  - Deadlock_detection_visitor now has m_table_shares_visited
    member which allows to support recursive locking for
    LOCK_open. This is required when deadlock detector
    inspects waiters graph which contains several edges
    representing waits for flushes or needs to come through
    the such edge more than once.
sql/mysqld.cc:
  Removed COND_refresh condition variable. See comment
  for sql_base.cc for details.
sql/mysqld.h:
  Removed COND_refresh condition variable. See comment
  for sql_base.cc for details.
sql/sql_base.cc:
  Changed approach to how threads are waiting for table
  to be flushed. Now thread that wants to wait for old
  table to go away subscribes for notification by adding
  Flush_ticket to table's share and waits using
  MDL_context::m_wait object. Once table gets flushed
  (i.e. all tables are closed and table share is ready
  to be destroyed) all such waiters are notified
  individually.
  Thanks to this change MDL deadlock detector can take
  such waits into account.
  
  To implement this/as result of this change:
  - tdc_wait_for_old_versions() was replaced with
    tdc_wait_for_old_version() which waits for individual
    old share to go away and which is called by open_table()
    after finding out that share is outdated. We don't
    need to perform back-off before such waiting thanks
    to the fact that deadlock detector now sees such waits.
  - As result Open_table_ctx::m_mdl_requests became
    unnecessary and was removed. We no longer allocate
    copies of MDL_request objects on MEM_ROOT when
    MYSQL_OPEN_FORCE_SHARED/SHARED_HIGH_PRIO flags are
    in effect.
  - close_cached_tables() and tdc_wait_for_old_version()
    share code which implements waiting for share to be
    flushed - the both use TABLE_SHARE::wait_until_flush()
    method. Thanks to this close_cached_tables() supports
    timeouts and has extra parameter for this.
  - Open_table_context::OT_MDL_CONFLICT enum element was
    renamed to OT_CONFLICT as it is now also used in cases
    when back-off is required to resolve deadlock caused
    by waiting for flush and not metadata lock.
  - In cases when we discover that current connection tries
    to open tables from different generation we now simply
    back-off and restart process of opening tables. To
    support this Open_table_context::OT_REOPEN_TABLES enum
    element was added.
  - COND_refresh condition variable became unnecessary and
    was removed.
  - mysql_notify_thread_having_shared_lock() no longer wakes
    up connections waiting for flush as all such connections
    can be waken up by deadlock detector if necessary.
sql/sql_base.h:
  - close_cached_tables() now has one more parameter -
    timeout for waiting for table to be flushed.
  - Open_table_context::OT_MDL_CONFLICT enum element was
    renamed to OT_CONFLICT as it is now also used in cases
    when back-off is required to resolve deadlock caused
    by waiting for flush and not metadata lock.
    Added new OT_REOPEN_TABLES enum element to be used in
    cases when we need to restart open tables process even
    in the middle of transaction.
  - Open_table_ctx::m_mdl_requests became unnecessary and
    was removed.
sql/sql_class.h:
  Added assert ensuring that we won't use LOCK_open mutex
  with THD::enter_cond(). Otherwise deadlocks can arise in
  MDL deadlock detector.
sql/sql_parse.cc:
  Changed FLUSH TABLES <list> WITH READ LOCK to take SNW
  metadata locks instead of X locks on tables to be flushed.
  Since we no longer require global IX lock to be taken
  when SNW locks are taken this makes this statement
  compatible with FLUSH TABLES WITH READ LOCK statement.
  Since SNW locks allow other connections to have table
  opened FLUSH TABLES <list> WITH READ LOCK now has to
  wait during open_tables() for old version to go away.
  Such waits can lead to deadlocks which will be detected
  by MDL deadlock detector which now takes waits for table
  to be flushed into account.
  
  Also adjusted code after adding one more parameter for
  close_cached_tables() call - timeout for waiting for
  table to be flushed.
sql/sql_yacc.yy:
  FLUSH TABLES <list> WITH READ LOCK now needs only SNW
  metadata locks on tables.
sql/sys_vars.cc:
  Adjusted code after adding one more parameter for
  close_cached_tables() call - timeout for waiting for
  table to be flushed.
sql/table.cc:
  Implemented new approach to how threads are waiting for
  table to be flushed. Now thread that wants to wait for
  old table to go away subscribes for notification by
  adding Flush_ticket to table's share and waits using
  MDL_context::m_wait object. Once table gets flushed
  (i.e. all tables are closed and table share is ready
  to be destroyed) all such waiters are notified
  individually. This change allows to make such waits
  visible inside of MDL deadlock detector.
  To do it:
  
  - Added list of waiters/Flush_tickets to TABLE_SHARE
    class.
  - Changed free_table_share() to postpone freeing of
    share memory until last waiter goes away and to
    wake up subscribed waiters.
  - Added TABLE_SHARE::wait_until_flushed() method which
    implements subscription to the list of waiters for
    table to be flushed and waiting for this event.
  
  Implemented interface which allows to expose waits for
  flushes to MDL deadlock detector:
  
  - Introduced Flush_ticket class a descendant of
    Wait_for_edge class.
  - Added TABLE_SHARE::find_deadlock() method which allows
    deadlock detector to find out what contexts are still
    using old version of table in question (i.e. to find
    out what contexts are waited for by owner of
    Flush_ticket).
sql/table.h:
  In order to support new strategy of waiting for table flush
  (see comment for table.cc for details) added list of
  waiters/Flush_tickets to TABLE_SHARE class.
  
  Implemented interface which allows to expose waits for
  flushes to MDL deadlock detector:
  - Introduced Flush_ticket class a descendant of
    Wait_for_edge class.
  - Added TABLE_SHARE::find_deadlock() method which allows
    deadlock detector to find out what contexts are still
    using old version of table in question (i.e. to find
    out what contexts are waited for by owner of
    Flush_ticket).

Remove dead and unused code.
Update to reflect the code review requests.

include/thr_lock.h:
  Remove declarations for THR_LOCK_OWNER,
  added along with the patch for sensitive cursors.
mysys/thr_lock.c:
  Remove support for multiple thr_lock requestors
  per THD.
sql/lock.cc:
  Revert the patch that added support for sensitive cursors.
sql/sp_rcontext.cc:
  Updated the use of mysql_open_cursor().
sql/sql_class.cc:
  Move the instance of Server_side_cursor
  from class Prepared_statement to class Statement.
sql/sql_class.h:
  Move the isntance of Server_side_cursor
  from class Prepared_statement to class
  Statement.
  Remove multiple lock_ids of thr_lock.
sql/sql_cursor.cc:
  Remove Sensitive_cursor implementation.
sql/sql_cursor.h:
  Remove declarations for sensitive cursors.
sql/sql_prepare.cc:
  Move the declaration of instance of Server_side_cursor
  from class Statement to class Prepared_statement, 
  where it's used.
sql/sql_select.cc:
  Remove sensitive cursor support.
sql/sql_select.h:
  Remove sensitive cursor support.
sql/sql_union.cc:
  Remove sensitive cursor support.

bytes_received/bytes_sent are ulonglong so they cannot be handled by the 
ulong handling code in add_to_status/add_diff_to_status().

Fixed by adding code to handle these two variables in 
add_to_status()/add_diff_to_status() and making sure they are not a subject
to the ulong handling 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.

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.

DROP USER 
RENAME USER CURRENT_USER() ...
GRANT ... TO CURRENT_USER()
REVOKE ... FROM CURRENT_USER()
ALTER DEFINER = CURRENT_USER() EVENTbut, When these statements are binlogged, CURRENT_USER() just is binlogged
as 'CURRENT_USER()', it is not expanded to the real user name. When slave 
executes the log event, 'CURRENT_USER()' is expand to the user of slave 
SQL thread, but SQL thread's user name always NULL. This breaks the replication.

After this patch, session's user will be written into query log events 
if these statements call CURREN_USER() or 'ALTER EVENT' does not assign a definer.


mysql-test/include/diff_tables.inc:
  Expend its abilities.
  Now it can diff not only in sessions of 'master' and 'slave', but 
  other sessions as well.
sql/log_event.cc:
  session's user will be written into Query_log_event, if is_current_user_used() is TRUE.
  On slave SQL thread, Only thd->invoker is written into Query_log_event,
  if it exists.
sql/sql_acl.cc:
  On slave SQL thread, grantor should copy from thd->invoker, if it exists
sql/sql_class.h:
  On slave SQL thread, thd->invoker is used to store the applying event's
  invoker.

Apart strict-aliasing warnings, fix the remaining warnings
generated by GCC 4.4.4 -Wall and -Wextra flags.

One major source of warnings was the in-house function my_bcmp
which (unconventionally) took pointers to unsigned characters
as the byte sequences to be compared. Since my_bcmp and bcmp
are deprecated functions whose only difference with memcmp is
the return value, every use of the function is replaced with
memcmp as the special return value wasn't actually being used
by any caller.

There were also various other warnings, mostly due to type
mismatches, missing return values, missing prototypes, dead
code (unreachable) and ignored return values.

BUILD/SETUP.sh:
  Remove flags that are implied by -Wall and -Wextra.
  Do not warn about unused parameters in C++.
BUILD/check-cpu:
  Print only the compiler version instead of verbose banner.
  Although the option is gcc specific, the check was only
  being used for GCC specific checks anyway.
client/mysql.cc:
  bcmp is no longer defined.
client/mysqltest.cc:
  Pass a string to function expecting a format string.
  Replace use of bcmp with memcmp.
cmd-line-utils/readline/Makefile.am:
  Always define _GNU_SOURCE when compiling GNU readline.
  Required to make certain prototypes visible.
cmd-line-utils/readline/input.c:
  Condition for the code to be meaningful.
configure.in:
  Remove check for bcmp.
extra/comp_err.c:
  Use appropriate type.
extra/replace.c:
  Replace use of bcmp with memcmp.
extra/yassl/src/crypto_wrapper.cpp:
  Do not ignore the return value of fgets. Retrieve the file
  position if fgets succeed -- if it fails, the function will
  bail out and return a error.
extra/yassl/taocrypt/include/blowfish.hpp:
  Use a single array instead of accessing positions of the sbox_
  through a subscript to pbox_.
extra/yassl/taocrypt/include/runtime.hpp:
  One definition of such functions is enough.
extra/yassl/taocrypt/src/aes.cpp:
  Avoid potentially ambiguous conditions.
extra/yassl/taocrypt/src/algebra.cpp:
  Rename arguments to avoid shadowing related warnings.
extra/yassl/taocrypt/src/blowfish.cpp:
  Avoid potentially ambiguous conditions.
extra/yassl/taocrypt/src/integer.cpp:
  Do not define type within a anonymous union.
  Use a variable to return a value instead of
  leaving the result in a register -- compiler
  does not know the logic inside the asm.
extra/yassl/taocrypt/src/misc.cpp:
  Define handler for pure virtual functions.
  Remove unused code.
extra/yassl/taocrypt/src/twofish.cpp:
  Avoid potentially ambiguous conditions.
extra/yassl/testsuite/test.hpp:
  Function must have C language linkage.
include/m_string.h:
  Remove check which relied on bcmp being defined -- they weren't
  being used as bcmp is only visible when _BSD_SOURCE is defined.
include/my_bitmap.h:
  Remove bogus helpers which were used only in a few files and
  were causing warnings about dead code.
include/my_global.h:
  Due to G++ bug, always silence false-positive uninitialized
  variables warnings when compiling C++ code with G++.
  Remove bogus helper.
libmysql/Makefile.shared:
  Remove built-in implementation of bcmp.
mysql-test/lib/My/SafeProcess/safe_process.cc:
  Cast pid to largest possible type for a process identifier.
mysys/mf_loadpath.c:
  Leave space of the ending nul.
mysys/mf_pack.c:
  Replace bcmp with memcmp.
mysys/my_bitmap.c:
  Dead code removal.
mysys/my_gethwaddr.c:
  Remove unused variable.
mysys/my_getopt.c:
  Silence bogus uninitialized variable warning.
  Do not cast away the constant qualifier.
mysys/safemalloc.c:
  Cast to expected type.
mysys/thr_lock.c:
  Silence bogus uninitialized variable warning.
sql/field.cc:
  Replace bogus helper with a more appropriate logic which is
  used throughout the code.
sql/item.cc:
  Remove bogus logical condition which always evaluates to TRUE.
sql/item_create.cc:
  Simplify code to avoid signedness related warnings.
sql/log_event.cc:
  Replace use of bcmp with memcmp.
  No need to use helpers for simple bit operations.
sql/log_event_old.cc:
  Replace bmove_align with memcpy.
sql/mysqld.cc:
  Move use declaration of variable to the ifdef block where it
  is used. Remove now-unnecessary casts and arguments.
sql/set_var.cc:
  Replace bogus helpers with simple and classic bit operations.
sql/slave.cc:
  Cast to expected type and silence bogus warning.
sql/sql_class.h:
  Don't use enum values as bit flags, the supposed type safety is
  bogus as the combined bit flags are not a value in the enumeration.
sql/udf_example.c:
  Only declare variable when necessary.
sql/unireg.h:
  Replace use of bmove_align with memcpy.
storage/innobase/os/os0file.c:
  Silence bogus warning.
storage/myisam/mi_open.c:
  Remove bogus cast, DBUG_DUMP expects a pointer to unsigned
  char.
storage/myisam/mi_page.c:
  Remove bogus cast, DBUG_DUMP expects a pointer to unsigned
  char.
strings/bcmp.c:
  Remove built-in bcmp.
strings/ctype-ucs2.c:
  Silence bogus warning.
tests/mysql_client_test.c:
  Use a appropriate type as expected by simple_command().

BUG#54872 MBR: replication failure caused by using tmp table inside transaction 
      
Changed criteria to classify a statement as unsafe in order to reduce the
number of spurious warnings. So a statement is classified as unsafe when
there is on-going transaction at any point of the execution if:

1. The mixed statement is about to update a transactional table and
a non-transactional table.

2. The mixed statement is about to update a temporary transactional
table and a non-transactional table.
      
3. The mixed statement is about to update a transactional table and
read from a non-transactional table.

4. The mixed statement is about to update a temporary transactional
table and read from a non-transactional table.

5. The mixed statement is about to update a non-transactional table
and read from a transactional table when the isolation level is
lower than repeatable read.

After updating a transactional table if:

6. The mixed statement is about to update a non-transactional table
and read from a temporary transactional table.
 
7. The mixed statement is about to update a non-transactional table
 and read from a temporary transactional table.

8. The mixed statement is about to update a non-transactionala table
   and read from a temporary non-transactional table.
     
9. The mixed statement is about to update a temporary non-transactional
table and update a non-transactional table.
     
10. The mixed statement is about to update a temporary non-transactional
table and read from a non-transactional table.
     
11. A statement is about to update a non-transactional table and the
option variables.binlog_direct_non_trans_update is OFF.

The reason for this is that locks acquired may not protected a concurrent
transaction of interfering in the current execution and by consequence in
the result. So the patch reduced the number of spurious unsafe warnings.

Besides we fixed a regression caused by BUG#51894, which makes temporary
tables to go into the trx-cache if there is an on-going transaction. In
MIXED mode, the patch for BUG#51894 ignores that the trx-cache may have
updates to temporary non-transactional tables that must be written to the
binary log while rolling back the transaction.
      
So we fix this problem by writing the content of the trx-cache to the
binary log while rolling back a transaction if a non-transactional
temporary table was updated and the binary logging format is MIXED.

DROP USER 
RENAME USER CURRENT_USER() ...
GRANT ... TO CURRENT_USER()
REVOKE ... FROM CURRENT_USER()
ALTER DEFINER = CURRENT_USER() EVENTbut, When these statements are binlogged, CURRENT_USER() just is binlogged
as 'CURRENT_USER()', it is not expanded to the real user name. When slave 
executes the log event, 'CURRENT_USER()' is expand to the user of slave 
SQL thread, but SQL thread's user name always NULL. This breaks the replication.

After this patch, session's user will be written into query log events 
if these statements call CURREN_USER() or 'ALTER EVENT' does not assign a definer.


mysql-test/include/diff_tables.inc:
  Expend its abilities.
  Now it can diff not only in sessions of 'master' and 'slave', but 
  other sessions as well.
mysql-test/include/rpl_diff_tables.inc:
  Diff the same table between master and slaves.
sql/log_event.cc:
  session's user will be written into Query_log_event, if is_current_user_used() is TRUE.
  On slave SQL thread, Only thd->variables.current_user is written into Query_log_event,
  if it exists.
sql/sql_acl.cc:
  On slave SQL thread, grantor should copy from thd->variables.current_user, if it exists
sql/sql_class.h:
  On slave SQL thread, thd->variables.current_user is used to store the applying event's
  invoker.

require O(#scans) memory

When an index merge operation was restarted, it would
re-allocate the Unique object controlling the duplicate row
ID elimination. Fixed by making the Unique object a member
of QUICK_INDEX_MERGE_SELECT and thus reusing it throughout
the lifetime of this object.

an atomic counter"

Split the large LOCK_open section in open_table(). 
Do not call open_table_from_share() under LOCK_open.
Remove thd->version.

This fixes
Bug#50589 "Server hang on a query evaluated using a temporary 
table"
Bug#51557 "LOCK_open and kernel_mutex are not happy together"
Bug#49463 "LOCK_table and innodb are not nice when handler 
instances are created".

This patch has effect on storage engines that rely on
ha_open() PSEA method being called under LOCK_open.
In particular:

1) NDB is broken and left unfixed. NDB relies on LOCK_open
being kept as part of ha_open(), since it uses auto-discovery.
While previously the NDB open code was race-prone, now
it simply fails on asserts.

2) HEAP engine had a race in ha_heap::open() when
a share for the same table could be added twice
to the list of shares, or a dangling reference to a share
stored in HEAP handler. This patch aims to address this
problem by 'pinning' the newly created share in the 
internal HEAP engine share list until at least one
handler instance is created using that share.


include/heap.h:
  Add members to HP_CREATE_INFO.
  Declare heap_release_share().
sql/lock.cc:
  Remove thd->version, use thd->open_tables->s->version instead.
sql/repl_failsafe.cc:
  Remove thd->version.
sql/sql_base.cc:
  - close_thread_table(): move handler cleanup code outside the critical section protected by LOCK_open.
  - remove thd->version
  - split the large critical section in open_table() that
  opens a new table from share and is protected by LOCK_open
  into 2 critical sections, thus reducing the critical path.
  - make check_if_table_exists() acquire LOCK_open internally.
  - use thd->open_tables->s->version instead of thd->refresh_version to make sure that all tables in
  thd->open_tables are in the same refresh series.
sql/sql_base.h:
  Add declaration for check_if_table_exists().
sql/sql_class.cc:
  Remove init_open_tables_state(), it's now equal to
  reset_open_tables_state().
sql/sql_class.h:
  Remove thd->version, THD::init_open_tables_state().
sql/sql_plugin.cc:
  Use table->m_needs_reopen to mark the table as stale
  rather than manipulate with thd->version, which is no more.
sql/sql_udf.cc:
  Use table->m_needs_reopen to mark the table as stale
  rather than manipulate with thd->version, which is no more.
sql/table.h:
  Remove an unused variable.
sql/tztime.cc:
  Use table->m_needs_reopen to mark the table as stale
  rather than manipulate with thd->version, which is no more.
storage/heap/CMakeLists.txt:
  Add heap tests to cmake build files.
storage/heap/ha_heap.cc:
  Fix a race when ha_heap::ha_open() could insert two 
  HP_SHARE objects into the internal share list or store
  a dangling reference to a share in ha_heap instance,
  or wrongly set implicit_emptied.
storage/heap/hp_create.c:
  Optionally pin a newly created share in the list of shares
  by increasing its open_count. This is necessary to 
  make sure that a newly created share doesn't disappear while
  a HP_INFO object is being created to reference it.
storage/heap/hp_open.c:
  When adding a new HP_INFO object to the list of objects
  in the heap share, make sure the open_count is not increased
  twice.
storage/heap/hp_test1.c:
  Adjust the test to new function signatures.
storage/heap/hp_test2.c:
  Adjust the test to new function signatures.

thd->open_tables"

thd->open_tables list is not normally accessed concurrently
except for one case: when the connection has open SQL
HANDLER tables, and we want to perform a DDL on the table,
we want to abort waits on MyISAM thr_lock of those connections
that prevent the DDL from proceeding, and iterate
over thd->open_tables list to find out the tables on which
the thread is waiting.

In 5.5 we mostly use deadlock detection and soft deadlock 
prevention, as opposed to "hard" deadlock prevention
of 5.1, which would abort any transaction that
may cause a deadlock. The only remaining case when
neither deadlock detection nor deadlock prevention
is implemented in 5.5 is HANDLER SQL, where we use
old good thr_lock_abort() technique form 5.1. 

Thus, replace use of LOCK_open to protect thd->open_tables
with thd->LOCK_ha_data (a lock protecting various session
private data).

This is a port of the work done for 5.5.4 for review
and inclusion into 5.5.5.

sql/sql_base.cc:
  Use thd->LOCK_ha_data (systematically) to set
  thd->open_tables.
sql/sql_class.h:
  Implement THD::set_open_tables().
sql/sql_cursor.cc:
  Use thd->LOCK_ha_data (systematically) to set
  thd->open_tables.
sql/sql_handler.cc:
  Use thd->LOCK_ha_data (systematically) to set
  thd->open_tables.
  Acquisition of LOCK_open is moved inside close_thread_table().
sql/sql_table.cc:
  Acquisition of LOCK_open is moved inside close_thread_tables().

In order to allow thread schedulers to be dynamically loaded,
it is necessary to make the following changes to the server:

- Two new service interfaces

- Modifications to InnoDB to inform the thread scheduler of state changes.

- Changes to the VIO subsystem for checking if data is available on a socket.

- Elimination of remains of the old thread pool implementation.

The two new service interfaces introduces are:

my_thread_scheduler
  A service interface to register a thread
  scheduler.

thd_wait
  A service interface to inform thread scheduler
  that the thread is about to start waiting.

In addition, the patch adds code that:

- Add a call to thd_wait for table locks in mysys
  thd_lock.c by introducing a set function that
  can be used to set a callback to be used when
  waiting on a lock and resuming from waiting.

- Calling the mysys set function from the server
  to set the callbacks correctly.

            
Some of the server implementations don't support dates later
than 2038 due to the internal time type being 32 bit.
Added checks so that the server will refuse dates that cannot
be handled by either throwing an error when setting date at 
runtime or by refusing to start or shutting down the server if 
the system date cannot be stored in my_time_t.

errors
            
In the fix of BUG#39934 in 5.1-rep+3, errors are generated when
binlog_format=row and a statement modifies a table restricted to
statement-logging (ER_BINLOG_ROW_MODE_AND_STMT_ENGINE); or if
binlog_format=statement and a statement modifies a table restricted to
row-logging (ER_BINLOG_STMT_MODE_AND_ROW_ENGINE).
            
However, some DDL statements that lock tables (e.g. ALTER TABLE,
CREATE INDEX and CREATE TRIGGER) were causing spurious errors,
although no row might be inserted into the binary log.
            
To fix the problem, we tagged statements that may generate
rows into the binary log and thence the warning messages are
only printed out when the appropriate conditions hold and rows
might be changed.

sql/log_event.cc:
  Reorganized the Query_log_event's constructor based on the
  CF_CAN_GENERATE_ROW_EVENTS flag and as such any statement
  that has the associated flag should go through a cache
  before being written to the binary log.
sql/share/errmsg-utf8.txt:
  Improved the error message ER_BINLOG_UNSAFE_MIXED_STATEMENT according to Paul's
  suggestion.
sql/sql_class.cc:
  Created a hook to be used by innodb that checks if a statement
  may write rows to the binary log. In other words, if it has
  the CF_CAN_GENERATE_ROW_EVENTS flag associated.
sql/sql_class.h:
  Defined the CF_CAN_GENERATE_ROW_EVENTS flag.
sql/sql_parse.cc:
  Updated the sql_command_flags and added a function to check the 
  CF_CAN_GENERATE_ROW_EVENTS.
sql/sql_parse.h:
  Added a function to check the CF_CAN_GENERATE_ROW_EVENTS.
storage/innobase/handler/ha_innodb.cc:
  Added a call to the hook thd_generates_rows().
storage/innobase/handler/ha_innodb.h:
  Defined an external reference to the hook thd_generates_rows().

 transactional SELECT and ALTER TABLE ...  REBUILD PARTITION".

Move declarations of sql_base.cc classes to sql_base.h
(previously declared in sql_class.h).
Became possible after a header file split.





sql/sql_base.cc:
  Make sql_base.h the first include in sql_base.cc.
sql/sql_base.h:
  Add declarations of Prelocking_strategy and Open_table_context.
sql/sql_class.h:
  Remove declarations of Prelocking_strategy and Open_table_context
  (moved).

Fix various mismatches between function's language linkage. Any
particular function that is declared in C++ but should be callable
from C must have C linkage. Note that function types with different
linkages are also distinct. Thus, if a function type is declared in
C code, it will have C linkage (same if declared in a extern "C"
block).

client/mysql.cc:
  Mismatch between prototype and declaration.
client/mysqltest.cc:
  mysqltest used to be C code. Use C linkage where appropriate.
cmd-line-utils/readline/input.c:
  Isolate unreachable code.
include/my_alloc.h:
  Function type must have C linkage.
include/my_base.h:
  Function type must have C linkage.
include/my_global.h:
  Add helper macros to avoid spurious namespace indentation.
include/mysql.h.pp:
  Update ABI file.
mysys/my_gethwaddr.c:
  Remove stray carriage return and fix coding style.
plugin/semisync/semisync_master_plugin.cc:
  Callback function types have C linkage.
plugin/semisync/semisync_slave_plugin.cc:
  Callback function types have C linkage.
sql/derror.cc:
  Expected function type has C linkage.
sql/field.cc:
  Use helper macro and fix indentation.
sql/handler.cc:
  Expected function type has C linkage.
sql/item_sum.cc:
  Correct function linkages. Remove now unnecessary cast.
sql/item_sum.h:
  Add prototypes with the appropriate linkage as otherwise they
  are distinct.
sql/mysqld.cc:
  Wrap functions in C linkage mode.
sql/opt_range.cc:
  C language linkage is ignored for class member functions.
sql/partition_info.cc:
  Add wrapper functions with C linkage for class member functions.
sql/rpl_utility.h:
  Use helper macro and fix indentation.
sql/sql_class.cc:
  Change type of thd argument -- THD is a class.
  Use helper macro and fix indentation.
sql/sql_class.h:
  Change type of thd argument -- THD is a class.
sql/sql_select.cc:
  Expected function type has C linkage.
sql/sql_select.h:
  Move prototype to sql_test.h
sql/sql_show.cc:
  Expected function type has C linkage.
sql/sql_test.cc:
  Fix required function prototype and fix coding style.
sql/sql_test.h:
  Removed unnecessary export and add another.
storage/myisammrg/ha_myisammrg.cc:
  Expected function type has C linkage.
storage/perfschema/pfs.cc:
  PSI headers are declared with C language linkage, which also
  applies to function types.

client/mysql.cc:
  Remove unused functions.
client/sql_string.cc:
  Remove unused functions.
include/my_pthread.h:
  Remove unused prototype.
mysys/my_pthread.c:
  Remove unused function.
sql/lock.cc:
  Remove unused function.
sql/lock.h:
  Remove unused and duplicated prototypes.
sql/sql_class.h:
  Removed unused variables.
sql/sql_const.h:
  Remove unused defines.
sql/sql_priv.h:
  Remove unused defines.
sql/sql_string.cc:
  Remove unused prototype.
sql/thr_malloc.cc:
  Remove unused function.
sql/thr_malloc.h:
  Remove unused prototype.
storage/myisam/CMakeLists.txt:
  Remove obsolete fulltext file.
storage/myisam/Makefile.am:
  Remove obsolete files (were already commented out).
storage/myisam/ft_eval.c:
  Remove obsolete fulltext file.
storage/myisam/ft_eval.h:
  Remove obsolete fulltext file.
storage/myisam/ft_stem.c:
  Remove obsolete fulltext file.
storage/myisam/ft_test1.c:
  Remove obsolete fulltext file.
storage/myisam/ft_test1.h:
  Remove obsolete fulltext file.

      
The thd->variables.option_bits & OPTION_BIN_LOG is currently abused: 
it's both a system variable and an implementation switch. The current
approach to this option bit breaks the session variable encapsulation. 
      
Besides it is allowed to change @@session.sql_bin_log within a
transaction what may lead to not correctly logging a transaction.
      
To fix the problems,  we created a thd->variables variable to represent
the "sql_log_bin" and prohibited its update inside a transaction or
sub-statement.

mysql-test/suite/binlog/r/binlog_stm_unsafe_warning.result:
  Updated result file. The reason the warnings are removed is
  related to BUG#50312.
mysql-test/suite/binlog/r/binlog_switch_inside_trans.result:
  Checks when is possible to change the option @@session.sql_log_bin.
mysql-test/suite/binlog/t/binlog_switch_inside_trans.test:
  Checks when is possible to change the option @@session.sql_log_bin.
mysql-test/suite/rpl/r/rpl_non_direct_stm_mixing_engines.result:
  Updated the result file with warnings that were being printed
  due to the wrong use of the thd->variables.option_bits and
  sql_log_bin_top_level variables.
mysql-test/suite/rpl/r/rpl_stm_mixing_engines.result:
  Updated the result file with warnings that were being printed
  due to the wrong use of the thd->variables.option_bits and
  sql_log_bin_top_level variables.
sql/share/errmsg-utf8.txt:
  Introduces two error messages to notify that the @@session.sql_log_bin
  cannot be changed inside a sub-statement or transaction.
sql/sql_base.cc:
  Removes the variable sql_log_bin_toplevel and uses
  the session variable sql_log_bin.
sql/sql_class.cc:
  Replaces the variable sql_log_bin_toplevel by the
  (variables.option_bits & OPTION_BIN_LOG).
sql/sql_class.h:
  Removes the variable sql_log_bin_toplevel and creates 
  a session variable sql_log_bin.
sql/sys_vars.cc:
  Checks when the sql_log_bin can be correctly updated.

transactional SELECT and ALTER TABLE ... REBUILD PARTITION".

The goal of this patch is to decouple type of metadata
lock acquired for table by open_tables() from type of
table-level lock to be acquired on it.

To achieve this we change approach to how we determine what
type of metadata lock should be acquired on table to be open.
Now instead of inferring it at open_tables() time from flags
and type of table-level lock we rely on that type of metadata
lock is properly set at parsing time and is not changed
further.

sql/ha_ndbcluster.cc:
  Now one needs to properly initialize table list element's
  MDL_request object before calling mysql_rm_table_part2().
sql/lock.cc:
  lock_table_names() no longer initializes table list elements'
  MDL_request objects. Now proper initialization of these
  requests is a responsibility of the caller.
sql/lock.h:
  Removed MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag which became
  unnecessary. Thanks to the fact that we don't reset type of
  requests for metadata locks between re-executions we now can
  figure out that upgradable locks are requested by simply
  looking at their type which were set in the parser. As result
  this flag became redundant.
sql/mdl.h:
  Added version of new operator which simplifies allocation of
  MDL_request objects on a MEM_ROOT.
sql/sp_head.cc:
  Added comment explaining why it is OK to infer type of
  metadata lock to request from type of table-level lock
  for prelocking.
  Added enum_mdl_type argument to sp_add_to_query_tables()
  to simplify its usage in trigger implementation.
sql/sp_head.h:
  Added enum_mdl_type argument to sp_add_to_query_tables()
  to simplify its usage in trigger implementation.
sql/sql_base.cc:
  - open_table_get_mdl_lock():
    Preserve type of MDL_request for table list element which
    was set in the parser by creating MDL_request objects on
    memory root if MYSQL_OPEN_FORCE_SHARED_MDL or
    MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL flag were specified.
    Thanks to this and to the fact that we no longer reset
    type of requests for metadata locks between re-executions
    we no longer need to acquire exclusive metadata lock on
    table to be created in a special way. This lock is acquired
    by code handling acquiring of upgradable locks.
    Also changed signature/calling convention for this function
    to simplify its usage.
  - Accordingly special lock strategy for table list elements
    which was used for such locks became unnecessary and was
    removed. Other strategies were renamed.
  - Since we no longer have guarantee that MDL_request object
    which were not satisfied due to lock conflict belongs to
    table list element Open_table_context class and its methods
    were extended to remember pointer to MDL_request which has
    caused problem at request_backoff_action() time and use it
    in recover_from_failed_open(). Similar approach is used
    for cases when problem from which we need to recover is
    not related to MDL but to the table itself. In this case
    we store pointer to the element of table list.
  - Changed open_tables()/open_tables_check_upgradable_mdl()/
    open_tables_acquire_upgradable_mdl() not to rely on
    MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag to understand when
    upgradable metadata locks should be acquired and not to
    infer type of MDL lock from type of table-level lock.
    Instead we assume that type of MDL to be acquired was set
    in the parser (we can do this as type of MDL_request is
    no longer reset between re-executions).
sql/sql_class.h:
  Since we no longer have guarantee that MDL_request object
  which were not satisfied due to lock conflict belongs to
  table list element Open_table_context class and its methods
  were extended to remember pointer to MDL_request which has
  caused problem at request_backoff_action() time and use it
  in recover_from_failed_open(). Similar approach is used
  for cases when problem from which we need to recover is
  not related to MDL but to the table itself. In this case
  we store pointer to the element of table list.
sql/sql_db.cc:
  Now one needs to properly initialize table list element's
  MDL_request object before calling mysql_rm_table_part2()
  or mysql_rename_tables().
sql/sql_lex.cc:
  st_select_lex/st_select_lex_node::add_table_to_list() method
  now has argument which allows specify type of metadata lock
  to be requested for table list element being added.
sql/sql_lex.h:
  - st_select_lex/st_select_lex_node::add_table_to_list()
    method now has argument which specifies type of metadata
    lock to be requested for table list element being added.
    This allows to explicitly set type of MDL lock to be
    acquired for a DDL statement in parser. It is also more
    future-proof than inferring type of MDL request from type
    of table-level lock.
  - Added Yacc_state::m_mdl_type member which specifies which
    type of metadata lock should be requested for tables to be
    added to table list by a grammar rule in cases when the same
    rule is used in several statements requiring different kinds
    of metadata locks.
sql/sql_parse.cc:
  - st_select_lex::add_table_to_list() method now has argument
    which specifies type of metadata lock to be requested for
    table list element being added. This allows to explicitly
    set type of MDL lock to be acquired for a DDL statement in
    parser. It is also more future-proof than inferring type of
    MDL request from type of table-level lock.
  - EXCLUSIVE_DOWNGRADABLE_MDL lock strategy has a new name -
    OTLS_DOWNGRADE_IF_EXISTS.
  - Adjusted LOCK TABLES implementation to the fact that we no
    longer infer type of metadata lock to be acquired from table
    level lock and that type of MDL request is set at parsing.
    And thus MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag became
    unnecessary.
sql/sql_prepare.cc:
  TABLE_LIST's lock strategy SHARED_MDL was renamed to OTLS_NONE
  as now it means that metadata lock should not be changed during
  call to open_table() (if it has been already acquired) and is
  also used for exclusive metadata lock.
sql/sql_show.cc:
  st_select_lex::add_table_to_list() method now has argument
  which specifies type of metadata lock to be requested for
  table list element being added.
sql/sql_table.cc:
  - Adjusted mysql_admin_table()'s code to the fact that
    open_tables() no longer determines what kind of metadata
    lock should be obtained basing on type of table-level
    lock and flags. Instead type of metadata lock for table
    to be open should be set before calling open_tables().
  - Changed mysql_alter_table() code to the facts:
    a) that now it is responsibility of caller to properly
    initalize MDL_request in table list elements before calling
    lock_table_names()
    b) and that MYSQL_OPEN_TAKE_UPGRADABLE_MDL is no longer
    necessary since type of metadata lock to be obtained
    at open_tables() time is set during parsing.
  - Changed code of mysql_recreate_table() to properly set
    type of metadata and table-level lock to be obtained
    by mysql_alter_table() which it calls.
sql/sql_trigger.cc:
  Instead of relying on MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag to
  force open_tables() to take an upgradable lock we now specify
  exact type of lock to be taken when constructing table list
  element for table to be open for CREATE/DROP TRIGGER.
sql/sql_view.cc:
  We no longer use TABLE_LIST::EXCLUSIVE_MDL strategy to force
  open_tables() to take an exclusive metadata lock on view to
  be created. Instead we rely on parser setting proper type of
  metadata lock to request and open_tables() acquiring it.
  This became possible thanks to the fact that we no longer
  reset type of MDL_request between statement re-executions.
sql/sql_yacc.yy:
  Instead of inferring type of MDL_request for table to be
  open from type of table-level lock and flags passed to
  open_tables() we now explicitly specify them at parsing.
  This became possible thanks to the fact that we no longer
  reset type of MDL_request between statement re-executions.
  In future this should allow to decouple type of metadata
  lock from type of table-level lock.
  The only exception to this approach is statements implemented
  through mysql_admin_table() which re-uses same table list
  element several times with different types of table-level
  and metadata locks.
  We now also properly initialize MDL_request objects for table
  list elements which are later passed to lock_table_names()
  function.
sql/table.cc:
  Do not reset type of MDL_request between statement
  re-executions. This became unnecessesary as we no longer
  change type of MDL_request residing in table list element.
  In its turn this change allows to set type of MDL_request
  only once - at parsing time.
sql/table.h:
  Got rid of TABLE_LIST::EXCLUSIVE_MDL lock strategy.
  Now we can specify that we need to acquire exclusive lock
  on table to be processed by open_tables() through setting
  an appropriate type of MDL_request at parsing time (this
  became possible thanks to the fact that we no longer reset
  types of MDL_request's belonging to table list elements
  between statement re-execution).
  Strategy SHARED_MDL was renamed to OTLS_NONE as now it
  means that metadata lock should not be changed during call
  to open_table() (if it has been already acquired) and is
  also used for exclusive metadata lock.
  Strategy EXCLUSIVE_DOWNGRADABLE_MDL was renamed to
  OTLS_DOWNGRADE_IF_EXISTS.

for ALTER TABLE, LOAD DATA).

ROW_COUNT is now assigned according to the following rules:

  - In my_ok():
    - for DML statements: to the number of affected rows;
    - for DDL statements: to 0.

  - In my_eof(): to -1 to indicate that there was a result set.

    We derive this semantics from the JDBC specification, where int
    java.sql.Statement.getUpdateCount() is defined to (sic) "return the
    current result as an update count; if the result is a ResultSet
    object or there are no more results, -1 is returned".

  - In my_error(): to -1 to be compatible with the MySQL C API and
    MySQL ODBC driver.

  - For SIGNAL statements: to 0 per WL#2110 specification. Zero is used
    since that's the "default" value of ROW_COUNT in the diagnostics area.

sql/protocol.cc:
  Fix a typo.
sql/sql_class.h:
  - Introduce THD::get_row_count_func() / THD::set_row_count_func();
  - Remove the CF_HAS_ROW_COUNT define
sql/sql_parse.cc:
  CF_HAS_ROW_COUNT was eliminated.

update statements
      
Only SELECT statements report any examined rows in the slow
log. Slow UPDATE, DELETE and INSERT statements report 0 rows
examined, unless the statement has a condition including a
SELECT substatement.
      
This patch adds counting of examined rows for the UPDATE and
DELETE statements. An INSERT ... VALUES statement will still 
not report any rows as examined.



sql/sql_class.h:
  Added more docs for THD::examined_row_count.
sql/sql_delete.cc:
  Add incrementing thd->examined_row_count.
sql/sql_update.cc:
  Add incrementing thd->examined_row_count.

Bug#20837 Apparent change of isolation level during transaction,
Bug#46527 COMMIT AND CHAIN RELEASE does not make sense,
Bug#53343 completion_type=1, COMMIT/ROLLBACK AND CHAIN don't 
preserve the isolation level
Bug#53346 completion_type has strange effect in a stored 
procedure/prepared statement

Make thd->tx_isolation mean strictly "current transaction 
isolation level"
Make thd->variables.tx_isolation mean "current session isolation
level".
The current transaction isolation level is now established
at transaction start. If there was a SET TRANSACTION
ISOLATION LEVEL statement, the value is taken from it.
Otherwise, the session value is used.
A change in a session value, made while a transaction is active,
whereas still allowed, no longer has any effect on the
current transaction isolation level. This is an incompatible
change.
A change in a session isolation level, made while there is
no active transaction, overrides SET TRANSACTION statement,
if there was any.
Changed the impelmentation to not look at @@session.completion_type
in the parser, and thus fixed Bug#53346.
Changed the parser to not allow AND NO CHAIN RELEASE,
and thus fixed Bug#46527.
Changed the transaction API to take the current transaction
isolation level into account:
- BEGIN/COMMIT now do preserve the current transaction
isolation level if chaining is on.
- implicit commit, XA COMMIT or XA ROLLBACK or autocommit don't.

thd->in_multi_stmt_transaction() and thd->active_transaction().


include/mysql_com.h:
  Comment SERVER_STATUS_IN_TRANS flag.
sql/ha_ndbcluster.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/handler.cc:
  Add comments.
sql/log.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/log_event.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/sql_base.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/sql_cache.cc:
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/sql_class.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/sql_class.h:
  Rename and comment two transaction processing- related methods.
sql/sql_parse.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/sql_prepare.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
sql/sql_rename.cc:
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/sql_table.cc:
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/sys_vars.cc:
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().
sql/transaction.cc:
  Rename: thd->in_multi_stmt_transaction() -> 
  thd->in_multi_stmt_transaction_mode().
  Rename: thd->active_transaction() ->
  thd->in_active_multi_stmt_transaction().

Statements with CONNECTION_ID were forced to be kept in the transactional
cache and by consequence non-transactional changes that were supposed to
be flushed ahead of the transaction were kept in the transactional cache.

This happened because after BUG#51894 any statement whose thd's
thread_specific_used was set was kept in the transactional cache. The idea
was to keep changes on temporary tables in the transactional cache. However,
the thread_specific_used was set not only for statements that accessed
temporary tables but also when the CONNECTION_ID was used.

To fix the problem, we created a new variable to keep track of updates
to temporary tables.


mysql-test/suite/rpl/r/rpl_temp_temporary.result:
  Added a test case.
mysql-test/suite/rpl/t/rpl_temp_temporary.test:
  Added a test case.
sql/log_event.cc:
  Uses the thread_temporary_used to decide if a statement should
  be kept in the transactional cache or not.
sql/sql_class.cc:
  Sets the thread_temporary_used while calling the decide_logging_format.
sql/sql_class.h:
  Defines the thread_temporary_used.
sql/sql_parse.cc:
  Resets the thread_temporary_used.

          transaction
BUG#52616 Temp table prevents switch binlog format from STATEMENT to ROW

Before the WL#2687 and BUG#46364, every non-transactional change that happened
after a transactional change was written to trx-cache and flushed upon
committing the transaction. WL#2687 and BUG#46364 changed this behavior and
non-transactional changes are now written to the binary log upon committing
the statement.

A binary log event is identified as transactional or non-transactional through
a flag in the Log_event which is set taking into account the underlie storage
engine on what it is stems from. In the current bug, this flag was not being
set properly when the DROP TEMPORARY TABLE was executed.

However, while fixing this bug we figured out that changes to temporary tables
should be always written to the trx-cache if there is an on-going transaction.
Otherwise, binlog events in the reversed order would be produced.

Regarding concurrency, keeping changes to temporary tables in the trx-cache is
also safe as temporary tables are only visible to the owner connection.

In this patch, we classify the following statements as unsafe:
   1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp

   2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam

   3 - CREATE TEMPORARY TABLE t_myisam_temp SELECT * FROM t_myisam

On the other hand, the following statements are classified as safe:

   1 - INSERT INTO t_innodb SELECT * FROM t_myisam_temp

   2 - INSERT INTO t_myisam_temp SELECT * FROM t_innodb

The patch also guarantees that transactions that have a DROP TEMPORARY are
always written to the binary log regardless of the mode and the outcome:
commit or rollback. In particular, the DROP TEMPORARY is extended with the
IF EXISTS clause when the current statement logging format is set to row.

Finally, the patch allows to switch from STATEMENT to MIXED/ROW when there
are temporary tables but the contrary is not possible.

mysql-test/extra/rpl_tests/rpl_binlog_max_cache_size.test:
  Updated the test case because 
     CREATE TEMPORARY TABLE t_innodb_temp SELECT * FROM t_myisam is not unsafe.
mysql-test/extra/rpl_tests/rpl_implicit_commit_binlog.test:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/extra/rpl_tests/rpl_innodb.test:
  Removed comments from the test case that became false after the patch.
mysql-test/extra/rpl_tests/rpl_loaddata.test:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
mysql-test/include/ctype_utf8_table.inc:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
mysql-test/r/ctype_cp932_binlog_stm.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/binlog/r/binlog_database.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/binlog/r/binlog_innodb_row.result:
  Updated the result file.
mysql-test/suite/binlog/r/binlog_multi_engine.result:
  Updated the unsafe message.
mysql-test/suite/binlog/r/binlog_row_binlog.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/binlog/r/binlog_row_drop_tmp_tbl.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/binlog/r/binlog_stm_binlog.result:
  Updated the result file.
mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/binlog/t/binlog_tmp_table.test:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
mysql-test/suite/ndb/r/ndb_binlog_format.result:
  Updated the unsafe message.
mysql-test/suite/rpl/r/rpl_concurrency_error.result:
  Updated the unsafe message.
mysql-test/suite/rpl/r/rpl_mixed_binlog_max_cache_size.result:
  Updated the result file because 
     CREATE TEMPORARY TABLE t_innodb_temp SELECT * FROM t_myisam is not unsafe.
mysql-test/suite/rpl/r/rpl_mixed_implicit_commit_binlog.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_mixed_mixing_engines.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_mixed_row_innodb.result:
  Added some comments to ease the understanding of the result file.
mysql-test/suite/rpl/r/rpl_non_direct_mixed_mixing_engines.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_non_direct_row_mixing_engines.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_non_direct_stm_mixing_engines.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_row_drop.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_row_implicit_commit_binlog.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_row_mixing_engines.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_stm_binlog_max_cache_size.result:
  Updated the result file because 
     CREATE TEMPORARY TABLE t_innodb_temp SELECT * FROM t_myisam is not unsafe.
mysql-test/suite/rpl/r/rpl_stm_implicit_commit_binlog.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_stm_innodb.result:
  Added some comments to ease the understanding of the result file.
mysql-test/suite/rpl/r/rpl_stm_mixing_engines.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl/r/rpl_stm_stop_middle_group.result:
  Updated the unsafe message.
mysql-test/suite/rpl/r/rpl_temp_temporary.result:
  Added a test case.
mysql-test/suite/rpl/t/rpl000013.test:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
  
     3 - CREATE TEMPORARY TABLE t_myisam_temp SELECT * FROM t_myisam
mysql-test/suite/rpl/t/rpl_misc_functions.test:
  Suppressed warning messages.
mysql-test/suite/rpl/t/rpl_temp_table.test:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
  
     3 - CREATE TEMPORARY TABLE t_myisam_temp SELECT * FROM t_myisam
mysql-test/suite/rpl/t/rpl_temp_temporary.test:
  Added a test case.
mysql-test/suite/rpl/t/rpl_temporary.test:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
  
     3 - CREATE TEMPORARY TABLE t_myisam_temp SELECT * FROM t_myisam
mysql-test/suite/rpl_ndb/r/rpl_ndb_row_implicit_commit_binlog.result:
  Updated the test case due to the new rules: changes to
  temporary tables are written to the binary log in the
  boundaries of a transaction if there is any.
mysql-test/suite/rpl_ndb/r/rpl_truncate_7ndb.result:
  Updated the test case to remove references to positions
  in the binary log.
mysql-test/suite/rpl_ndb/t/rpl_truncate_7ndb.test:
  Updated the test case to remove references to positions
  in the binary log.
mysql-test/t/create_select_tmp.test:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
  
     3 - CREATE TEMPORARY TABLE t_myisam_temp SELECT * FROM t_myisam
mysql-test/t/ctype_cp932_binlog_stm.test:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
  
     3 - CREATE TEMPORARY TABLE t_myisam_temp SELECT * FROM t_myisam
mysql-test/t/mysqlbinlog.test:
  Suppressed warning messages due to the following cases:
  
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
  
     3 - CREATE TEMPORARY TABLE t_myisam_temp SELECT * FROM t_myisam
sql/log.cc:
  Improved the code by creating several functions to hide decision
  on type of engine changed, commit/abort, etc:  
  
  . stmt_has_updated_non_trans_table
  
  . trans_has_updated_non_trans_table
  
  . ending_trans
  
  Updated the binlog_rollback function and the use of the 
  OPTION_KEEP_LOG which indincates when a temporary table was
  either created or dropped and as such the command must be 
  logged if not in MIXED mode and even while rolling back the
  transaction.
sql/log.h:
  Improved the code by creating several functions to hide decision
  on type of engine changed, commit/abort, etc.
sql/log_event.cc:
  Removed the setting of the OPTION_KEEP_LOG as it is related to CREATE
  TEMPORARY and DROP TEMPORARY and not to the type of engine (i.e.
  transactional or non-transactional).
sql/log_event_old.cc:
  Removed the setting of the OPTION_KEEP_LOG as it is related to CREATE
  TEMPORARY and DROP TEMPORARY and not to the type of engine (i.e.
  transactional or non-transactional).
sql/share/errmsg-utf8.txt:
  Updated the unsafe message.
sql/sql_class.cc:
  Classifies the following statements as unsafe:
     1 - INSERT INTO t_myisam SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_myisam
  
  On the other hand, the following statements are classified as safe:
  
     1 - INSERT INTO t_innodb SELECT * FROM t_myisam_temp
  
     2 - INSERT INTO t_myisam_temp SELECT * FROM t_innodb
sql/sql_class.h:
  It allows to switch from STATEMENT to MIXED/ROW when there are temporary
  tables but the contrary is not possible.
sql/sql_table.cc:
  Fixed the case that a DROP/DROP TEMPORARY that affects a temporary table in MIXED
  mode is written as a DROP TEMPORARY TABLE IF EXISTS because the table may not exist in the slave and due to the IF EXISTS token an error will never happen
  while processing the statement in the slave.
  
  Removed a function that was not being used.

            to cleanup open connections

It was possible to UNINSTALL storage engine plugin when binding
between THD object and storage engine is still active (e.g. in
the middle of transaction).

To avoid unclean deactivation (uninstall) of storage engine plugin
in the middle of transaction, additional storage engine plugin
lock is acquired by thd_set_ha_data().

If ha_data is not null and storage engine plugin was not locked
by thd_set_ha_data() in this connection before, storage engine
plugin gets locked.

If ha_data is null and storage engine plugin was locked by
thd_set_ha_data() in this connection before, storage engine
plugin lock gets released.

If handlerton::close_connection() didn't reset ha_data, server does
it immediately after calling handlerton::close_connection().

Note that this is just a framework fix, storage engines must switch
to thd_set_ha_data() from thd_ha_data() if they want to see fit.

include/mysql/plugin.h:
  As thd_{get|set}_ha_data() have some extra logic now, they
  must be implemented on server side.
include/mysql/plugin.h.pp:
  As thd_{get|set}_ha_data() have some extra logic now, they
  must be implemented on server side.
sql/handler.cc:
  Make sure ha_data is reset and ha_data lock is released.
sql/handler.h:
  hton is not supposed to be updated by ha_lock_engine(),
  make it const.
sql/sql_class.cc:
  As thd_{get|set}_ha_data() have some extra logic now, they
  must be implemented on server side.
sql/sql_class.h:
  Added ha_data lock.

Adding my_global.h first in all files using
NO_EMBEDDED_ACCESS_CHECKS.

Correcting a merge problem resulting from a changed definition
of check_some_access compared to the original patches.

This patch:

- Moves all definitions from the mysql_priv.h file into
  header files for the component where the variable is
  defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h

CHECK_FIELD_IGNORE was treated as CHECK_FIELD_ERROR_FOR_NULL;
UPDATE...SET...NULL on NOT NULL fields behaved differently after
a trigger.

Now distinguishes between IGNORE and ERROR_FOR_NULL and save/restores
check-field options.


mysql-test/r/trigger.result:
  Show that UPDATE...SET...NULL on NOT NULL columns doesn't behave differently
  when run after a trigger.
mysql-test/t/trigger.test:
  Show that UPDATE...SET...NULL on NOT NULL columns doesn't behave differently
  when run after a trigger.
sql/field_conv.cc:
  CHECK_FIELD_IGNORE was treated as CHECK_FIELD_ERROR_FOR_NULL.
  Distinguish between the two.
sql/sp_head.cc:
  Raise error as needed.
sql/sql_class.cc:
  Save and restore check-fields options.
sql/sql_class.h:
  Make room so we can save check-fields options.
sql/sql_insert.cc:
  Raise error as needed.

In BUG#49562 we fixed the case where numeric user var events
would not serialize the flag stating whether the value was signed
or unsigned (unsigned_flag). This fixed the case that the slave
would get an overflow while treating the unsigned values as
signed.
      
In this bug, we find that the unsigned_flag can sometimes change
between the moment that the user value is recorded for binlogging
purposes and the actual binlogging time. Since we take the
unsigned_flag from the runtime variable data, at binlogging time,
and the variable value is comes from the copy taken earlier in
the execution, there may be inconsistency in the
User_var_log_event between the variable value and its
unsigned_flag.
      
We fix this by also copying the unsigned_flag of the
user_var_entry when its value is copied, for binlogging
purposes. Later, at binlogging time, we use the copied
unsigned_flag and not the one in the runtime user_var_entry
instance.

Remove unnecessary need_reopen loops.