The problem was that server didn't check resulting size of prepared
statement argument which was set using mysql_send_long_data() API.
By calling mysql_send_long_data() several times it was possible
to create overly big string and thus force server to allocate
memory for it. There was no way to limit this allocation.

The solution is to add check for size of result string against
value of max_long_data_size start-up parameter. When intermediate
string exceeds max_long_data_size value an appropriate error message
is emitted.

We can't use existing max_allowed_packet parameter for this purpose
since its value is limited by 1GB and therefore using it as a limit
for data set through mysql_send_long_data() API would have been an
incompatible change. Newly introduced max_long_data_size parameter
gets value from max_allowed_packet parameter unless its value is
specified explicitly. This new parameter is marked as deprecated
and will be eventually replaced by max_allowed_packet parameter.
Value of max_long_data_size parameter can be set only at server
startup.


mysql-test/t/variables.test:
  Added checking for new start-up parameter max_long_data_size.
sql/item.cc:
  Added call to my_message() when accumulated string exceeds
  max_long_data_size value. my_message() calls error handler
  that was installed in mysql_stmt_get_longdata before call
  to Item_param::set_longdata.
  
  The error handler then sets state, last_error and last_errno
  fields for current statement to values which correspond to
  error which was caught.
sql/mysql_priv.h:
  Added max_long_data_size variable declaration.
sql/mysqld.cc:
  Added support for start-up parameter 'max_long_data_size'.
  This parameter limits size of data which can be sent from
  client to server using mysql_send_long_data() API.
sql/set_var.cc:
  Added variable 'max_long_data_size' into list of variables
  displayed by command 'show variables'.
sql/sql_prepare.cc:
  Added error handler class Set_longdata_error_handler.
  This handler is used to catch any errors that can be
  generated during execution of Item_param::set_longdata().
  
  Source code snippet that makes checking for statement's state 
  during statement execution is moved from Prepared_statement::execute()
  to Prepared_statement::execute_loop() in order not to call
  set_parameters() when statement has failed during
  set_long_data() execution. If this hadn't been done
  the call to set_parameters() would have failed.
tests/mysql_client_test.c:
  A testcase for the bug #56976 was added.

> ------------------------------------------------------------
> revno: 3520
> revision-id: sergey.glukhov@oracle.com-20101214093303-wmo9mqcb8rz0wv9f
> parent: tor.didriksen@oracle.com-20101213161301-81lprlbune7r98dl
> committer: Sergey Glukhov <sergey.glukhov@oracle.com>
> branch nick: mysql-5.1-bugteam
> timestamp: Tue 2010-12-14 12:33:03 +0300
> message:
>   Fixed following problems:
>   --Bug#52157 various crashes and assertions with multi-table update, stored function
>   --Bug#54475 improper error handling causes cascading crashing failures in innodb/ndb
>   --Bug#57703 create view cause Assertion failed: 0, file .\item_subselect.cc, line 846
>   --Bug#57352 valgrind warnings when creating view
>   --Recently discovered problem when a nested materialized derived table is used
>     before being populated and it leads to incorrect result
>   
>   We have several modes when we should disable subquery evaluation.
>   The reasons for disabling are different. It could be
>   uselessness of the evaluation as in case of 'CREATE VIEW'
>   or 'PREPARE stmt', or we should disable subquery evaluation
>   if tables are not locked yet as it happens in bug#54475, or
>   too early evaluation of subqueries can lead to wrong result
>   as it happened in Bug#19077.
>   Main problem is that if subquery items are treated as const
>   they are evaluated in ::fix_fields(), ::fix_length_and_dec()
>   of the parental items as a lot of these methods have
>   Item::val_...() calls inside.
>   We have to make subqueries non-const to prevent unnecessary
>   subquery evaluation. At the moment we have different methods
>   for this. Here is a list of these modes:
>   
>   1. PREPARE stmt;
>   We use UNCACHEABLE_PREPARE flag.
>   It is set during parsing in sql_parse.cc, mysql_new_select() for
>   each SELECT_LEX object and cleared at the end of PREPARE in
>   sql_prepare.cc, init_stmt_after_parse(). If this flag is set
>   subquery becomes non-const and evaluation does not happen.
>   
>   2. CREATE|ALTER VIEW, SHOW CREATE VIEW, I_S tables which
>      process FRM files
>   We use LEX::view_prepare_mode field. We set it before
>   view preparation and check this flag in
>   ::fix_fields(), ::fix_length_and_dec().
>   Some bugs are fixed using this approach,
>   some are not(Bug#57352, Bug#57703). The problem here is
>   that we have a lot of ::fix_fields(), ::fix_length_and_dec()
>   where we use Item::val_...() calls for const items.
>   
>   3. Derived tables with subquery = wrong result(Bug19077)
>   The reason of this bug is too early subquery evaluation.
>   It was fixed by adding Item::with_subselect field
>   The check of this field in appropriate places prevents
>   const item evaluation if the item have subquery.
>   The fix for Bug19077 fixes only the problem with
>   convert_constant_item() function and does not cover
>   other places(::fix_fields(), ::fix_length_and_dec() again)
>   where subqueries could be evaluated.
>   
>   Example:
>   CREATE TABLE t1 (i INT, j BIGINT);
>   INSERT INTO t1 VALUES (1, 2), (2, 2), (3, 2);
>   SELECT * FROM (SELECT MIN(i) FROM t1
>   WHERE j = SUBSTRING('12', (SELECT * FROM (SELECT MIN(j) FROM t1) t2))) t3;
>   DROP TABLE t1;
>   
>   4. Derived tables with subquery where subquery
>      is evaluated before table locking(Bug#54475, Bug#52157)
>   
>   Suggested solution is following:
>   
>   -Introduce new field LEX::context_analysis_only with the following
>    possible flags:
>    #define CONTEXT_ANALYSIS_ONLY_PREPARE 1
>    #define CONTEXT_ANALYSIS_ONLY_VIEW    2
>    #define CONTEXT_ANALYSIS_ONLY_DERIVED 4
>   -Set/clean these flags when we perform
>    context analysis operation
>   -Item_subselect::const_item() returns
>    result depending on LEX::context_analysis_only.
>    If context_analysis_only is set then we return
>    FALSE that means that subquery is non-const.
>    As all subquery types are wrapped by Item_subselect
>    it allow as to make subquery non-const when
>    it's necessary.

- Removed files specific to compiling on OS/2
- Removed files specific to SCO Unix packaging
- Removed "libmysqld/copyright", text is included in documentation
- Removed LaTeX headers for NDB Doxygen documentation
- Removed obsolete NDB files
- Removed "mkisofs" binaries
- Removed the "cvs2cl.pl" script
- Changed a few GPL texts to use "program" instead of "library"

--Bug#52157 various crashes and assertions with multi-table update, stored function
--Bug#54475 improper error handling causes cascading crashing failures in innodb/ndb
--Bug#57703 create view cause Assertion failed: 0, file .\item_subselect.cc, line 846
--Bug#57352 valgrind warnings when creating view
--Recently discovered problem when a nested materialized derived table is used
  before being populated and it leads to incorrect result

We have several modes when we should disable subquery evaluation.
The reasons for disabling are different. It could be
uselessness of the evaluation as in case of 'CREATE VIEW'
or 'PREPARE stmt', or we should disable subquery evaluation
if tables are not locked yet as it happens in bug#54475, or
too early evaluation of subqueries can lead to wrong result
as it happened in Bug#19077.
Main problem is that if subquery items are treated as const
they are evaluated in ::fix_fields(), ::fix_length_and_dec()
of the parental items as a lot of these methods have
Item::val_...() calls inside.
We have to make subqueries non-const to prevent unnecessary
subquery evaluation. At the moment we have different methods
for this. Here is a list of these modes:

1. PREPARE stmt;
We use UNCACHEABLE_PREPARE flag.
It is set during parsing in sql_parse.cc, mysql_new_select() for
each SELECT_LEX object and cleared at the end of PREPARE in
sql_prepare.cc, init_stmt_after_parse(). If this flag is set
subquery becomes non-const and evaluation does not happen.

2. CREATE|ALTER VIEW, SHOW CREATE VIEW, I_S tables which
   process FRM files
We use LEX::view_prepare_mode field. We set it before
view preparation and check this flag in
::fix_fields(), ::fix_length_and_dec().
Some bugs are fixed using this approach,
some are not(Bug#57352, Bug#57703). The problem here is
that we have a lot of ::fix_fields(), ::fix_length_and_dec()
where we use Item::val_...() calls for const items.

3. Derived tables with subquery = wrong result(Bug19077)
The reason of this bug is too early subquery evaluation.
It was fixed by adding Item::with_subselect field
The check of this field in appropriate places prevents
const item evaluation if the item have subquery.
The fix for Bug19077 fixes only the problem with
convert_constant_item() function and does not cover
other places(::fix_fields(), ::fix_length_and_dec() again)
where subqueries could be evaluated.

Example:
CREATE TABLE t1 (i INT, j BIGINT);
INSERT INTO t1 VALUES (1, 2), (2, 2), (3, 2);
SELECT * FROM (SELECT MIN(i) FROM t1
WHERE j = SUBSTRING('12', (SELECT * FROM (SELECT MIN(j) FROM t1) t2))) t3;
DROP TABLE t1;

4. Derived tables with subquery where subquery
   is evaluated before table locking(Bug#54475, Bug#52157)

Suggested solution is following:

-Introduce new field LEX::context_analysis_only with the following
 possible flags:
 #define CONTEXT_ANALYSIS_ONLY_PREPARE 1
 #define CONTEXT_ANALYSIS_ONLY_VIEW    2
 #define CONTEXT_ANALYSIS_ONLY_DERIVED 4
-Set/clean these flags when we perform
 context analysis operation
-Item_subselect::const_item() returns
 result depending on LEX::context_analysis_only.
 If context_analysis_only is set then we return
 FALSE that means that subquery is non-const.
 As all subquery types are wrapped by Item_subselect
 it allow as to make subquery non-const when
 it's necessary.


mysql-test/r/derived.result:
  test case
mysql-test/r/multi_update.result:
  test case
mysql-test/r/view.result:
  test case
mysql-test/suite/innodb/r/innodb_multi_update.result:
  test case
mysql-test/suite/innodb/t/innodb_multi_update.test:
  test case
mysql-test/suite/innodb_plugin/r/innodb_multi_update.result:
  test case
mysql-test/suite/innodb_plugin/t/innodb_multi_update.test:
  test case
mysql-test/t/derived.test:
  test case
mysql-test/t/multi_update.test:
  test case
mysql-test/t/view.test:
  test case
sql/item.cc:
  --removed unnecessary code
sql/item_cmpfunc.cc:
  --removed unnecessary checks
  --THD::is_context_analysis_only() is replaced with LEX::is_ps_or_view_context_analysis()
sql/item_func.cc:
  --refactored context analysis checks
sql/item_row.cc:
  --removed unnecessary checks
sql/item_subselect.cc:
  --removed unnecessary code
  --added DBUG_ASSERT into Item_subselect::exec()
    which asserts that subquery execution can not happen
    if LEX::context_analysis_only is set, i.e. at context
    analysis stage.
  --Item_subselect::const_item()
    Return FALSE if LEX::context_analysis_only is set.
    It prevents subquery evaluation in ::fix_fields &
    ::fix_length_and_dec at context analysis stage.
sql/item_subselect.h:
  --removed unnecessary code
sql/mysql_priv.h:
  --Added new set of flags.
sql/sql_class.h:
  --removed unnecessary code
sql/sql_derived.cc:
  --added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_lex.cc:
  --init LEX::context_analysis_only field
sql/sql_lex.h:
  --New LEX::context_analysis_only field
sql/sql_parse.cc:
  --removed unnecessary code
sql/sql_prepare.cc:
  --removed unnecessary code
  --added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_select.cc:
  --refactored context analysis checks
sql/sql_show.cc:
  --added LEX::context_analysis_only analysis intialization/cleanup
sql/sql_view.cc:
  --added LEX::context_analysis_only analysis intialization/cleanup

Fixed the references to security_ctx->priv_user
to be real char * pointers instead of a C array name reference.
This is somehow important for some 3d party 
dtrace replacements

Problem: Extended characters outside of ASCII range where not displayed
properly in SHOW PROCESSLIST, because thd_info->query was always sent as 
system_character_set (utf8). This was wrong, because query buffer
is never converted to utf8 - it is always have client character set.

Fix: sending query buffer using query character set

  @ sql/sql_class.cc
  @ sql/sql_class.h
    Introducing a new class CSET_STRING, a LEX_STRING with character set.
    Adding set_query(&CSET_STRING)
    Adding reset_query(), to use instead of set_query(0, NULL).

  @ sql/event_data_objects.cc
    Using reset_query()

  @ sql/log_event.cc
    Using reset_query()
    Adding charset argument to set_query_and_id().

  @ sql/slave.cc
    Using reset_query().

  @ sql/sp_head.cc
    Changing backing up and restore code to use CSET_STRING.

  @ sql/sql_audit.h
    Using CSET_STRING.
    In the "else" branch it's OK not to use
    global_system_variables.character_set_client.
    &my_charset_latin1, which is set in constructor, is fine
    (verified with Sergey Vojtovich).

  @ sql/sql_insert.cc
    Using set_query() with proper character set: table_name is utf8.

  @ sql/sql_parse.cc
    Adding character set argument to set_query_and_id().
    (This is the main point where thd->charset() is stored
     into thd->query_string.cs, for use in "SHOW PROCESSLIST".)
    Using reset_query().
    
  @ sql/sql_prepare.cc
    Storing client character set into thd->query_string.cs.

  @ sql/sql_show.cc
    Using CSET_STRING to fetch and send charset-aware query information
    from threads.

  @ storage/myisam/ha_myisam.cc
    Using set_query() with proper character set: table_name is utf8.

  @ mysql-test/r/show_check.result
  @ mysql-test/t/show_check.test
    Adding tests

           during EXPLAIN

Before the patch, send_eof() of some subclasses of 
select_result (e.g., select_send::send_eof()) could 
handle being called after an error had occured while others 
could not. The methods that were not well-behaved would trigger
an ASSERT on debug builds. Release builds were not affected.

Consider the following query as an example for how the ASSERT
could be triggered:

A user without execute privilege on f() does
   SELECT MAX(key1) INTO @dummy FROM t1 WHERE f() < 1;
resulting in "ERROR 42000: execute command denied to user..." 

The server would end the query by calling send_eof(). The 
fact that the error had occured would make the ASSERT trigger. 

select_dumpvar::send_eof() was the offending method in the
bug report, but the problem also applied to other 
subclasses of select_result. This patch uniforms send_eof() 
of all subclasses of select_result to handle being called 
after an error has occured. 

mysql-test/r/not_embedded_server.result:
  Added test for BUG#54812
mysql-test/t/not_embedded_server.test:
  Added test for BUG#54812
sql/sql_class.cc:
  send_eof() of all subclasses of select_result can now handle being
  called after an error has occured.
sql/sql_insert.cc:
  send_eof() of all subclasses of select_result can now handle being
  called after an error has occured.
  Also fix call to abort() in select_create::send_eof(), which was supposed to abort the result set, not terminate the server. This call to abort() should have been changed when the function was renamed from abort_result_set() but was forgotten. New test case added by BUG#54812 covered this line and terminated server.
sql/sql_prepare.cc:
  send_eof() of all subclasses of select_result can now handle being
  called after an error has occured.
sql/sql_update.cc:
  send_eof() of all subclasses of select_result can now handle being
  called after an error has occured.

structure buffer).

This is a follow-up for WL#4435. The bug actually existed not only
MYSQL_TYPE_DATETIME type. The problem was that Item_param::set_value()
was written in an assumption that it's working with expressions, i.e.
with basic data types.

There are two different quick fixes here:
  a) Change Item_param::make_field() -- remove setting of
     Send_field::length, Send_field::charsetnr, Send_field::flags and
     Send_field::type.

     That would lead to marshalling all data using basic types to the client
     (MYSQL_TYPE_LONGLONG, MYSQL_TYPE_DOUBLE, MYSQL_TYPE_STRING and
     MYSQL_TYPE_NEWDECIMAL). In particular, that means, DATETIME would be
     sent as MYSQL_TYPE_STRING, TINYINT -- as MYSQL_TYPE_LONGLONG, etc.

     That could be Ok for the client, because the client library does
     reverse conversion automatically (the client program would see DATETIME
     as MYSQL_TIME object). However, there is a problem with metadata --
     the metadata would be wrong (misleading): it would say that DATETIME is
     marshaled as MYSQL_TYPE_DATETIME, not as MYSQL_TYPE_STRING.

  b) Set Item_param::param_type properly to actual underlying field type.
     That would lead to double conversion inside the server: for example,
     MYSQL_TIME-object would be converted into STRING-object
     (in Item_param::set_value()), and then converted back to MYSQL_TIME-object
     (in Item_param::send()).

     The data however would be marshalled more properly, and also metadata would
     be correct.

This patch implements b).

There is also a possibility to avoid double conversion either by clonning
the data field, or by storing a reference to it and using it on Item::send()
time. That requires more work and might be done later.

bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ
LOCK" and bug #54673 "It takes too long to get readlock for
'FLUSH TABLES WITH READ LOCK'".

The first bug manifested itself as a deadlock which occurred
when a connection, which had some table open through HANDLER
statement, tried to update some data through DML statement
while another connection tried to execute FLUSH TABLES WITH
READ LOCK concurrently.

What happened was that FTWRL in the second connection managed
to perform first step of GRL acquisition and thus blocked all
upcoming DML. After that it started to wait for table open
through HANDLER statement to be flushed. When the first connection
tried to execute DML it has started to wait for GRL/the second
connection creating deadlock.

The second bug manifested itself as starvation of FLUSH TABLES
WITH READ LOCK statements in cases when there was a constant
stream of concurrent DML statements (in two or more
connections).

This has happened because requests for protection against GRL
which were acquired by DML statements were ignoring presence of
pending GRL and thus the latter was starved.

This patch solves both these problems by re-implementing GRL
using metadata locks.

Similar to the old implementation acquisition of GRL in new
implementation is two-step. During the first step we block
all concurrent DML and DDL statements by acquiring global S
metadata lock (each DML and DDL statement acquires global IX
lock for its duration). During the second step we block commits
by acquiring global S lock in COMMIT namespace (commit code
acquires global IX lock in this namespace).

Note that unlike in old implementation acquisition of
protection against GRL in DML and DDL is semi-automatic.
We assume that any statement which should be blocked by GRL
will either open and acquires write-lock on tables or acquires
metadata locks on objects it is going to modify. For any such
statement global IX metadata lock is automatically acquired
for its duration.

The first problem is solved because waits for GRL become
visible to deadlock detector in metadata locking subsystem
and thus deadlocks like one in the first bug become impossible.

The second problem is solved because global S locks which
are used for GRL implementation are given preference over
IX locks which are acquired by concurrent DML (and we can
switch to fair scheduling in future if needed).

Important change:
FTWRL/GRL no longer blocks DML and DDL on temporary tables.
Before this patch behavior was not consistent in this respect:
in some cases DML/DDL statements on temporary tables were
blocked while in others they were not. Since the main use cases
for FTWRL are various forms of backups and temporary tables are
not preserved during backups we have opted for consistently
allowing DML/DDL on temporary tables during FTWRL/GRL.

Important change:
This patch changes thread state names which are used when
DML/DDL of FTWRL is waiting for global read lock. It is now
either "Waiting for global read lock" or "Waiting for commit
lock" depending on the stage on which FTWRL is.

Incompatible change:
To solve deadlock in events code which was exposed by this
patch we have to replace LOCK_event_metadata mutex with
metadata locks on events. As result we have to prohibit
DDL on events under LOCK TABLES.

This patch also adds extensive test coverage for interaction
of DML/DDL and FTWRL.

Performance of new and old global read lock implementations
in sysbench tests were compared. There were no significant
difference between new and old implementations.

mysql-test/include/check_ftwrl_compatible.inc:
  Added helper script which allows to check that a statement is
  compatible with FLUSH TABLES WITH READ LOCK.
mysql-test/include/check_ftwrl_incompatible.inc:
  Added helper script which allows to check that a statement is
  incompatible with FLUSH TABLES WITH READ LOCK.
mysql-test/include/handler.inc:
  Adjusted test case to the fact that now DROP TABLE closes
  open HANDLERs for the table to be dropped before checking
  if there active FTWRL in this connection.
mysql-test/include/wait_show_condition.inc:
  Fixed small error in the timeout message. The correct name
  of variable used as parameter for this script is "$condition"
  and not "$wait_condition".
mysql-test/r/delayed.result:
  Added test coverage for scenario which triggered assert in
  metadata locking subsystem.
mysql-test/r/events_2.result:
  Updated test results after prohibiting event DDL operations
  under LOCK TABLES.
mysql-test/r/flush.result:
  Added test coverage for bug #57006 "Deadlock between HANDLER
  and FLUSH TABLES WITH READ LOCK".
mysql-test/r/flush_read_lock.result:
  Added test coverage for various aspects of FLUSH TABLES WITH
  READ LOCK functionality.
mysql-test/r/flush_read_lock_kill.result:
  Adjusted test case after replacing custom global read lock
  implementation with one based on metadata locks. Use new
  debug_sync point. Do not disable concurrent inserts as now
  InnoDB we always use InnoDB table.
mysql-test/r/handler_innodb.result:
  Adjusted test case to the fact that now DROP TABLE closes
  open HANDLERs for the table to be dropped before checking
  if there active FTWRL in this connection.
mysql-test/r/handler_myisam.result:
  Adjusted test case to the fact that now DROP TABLE closes
  open HANDLERs for the table to be dropped before checking
  if there active FTWRL in this connection.
mysql-test/r/mdl_sync.result:
  Adjusted test case after replacing custom global read lock
  implementation with one based on metadata locks. Replaced
  usage of GRL-specific debug_sync's with appropriate sync
  points in MDL subsystem.
mysql-test/suite/perfschema/r/dml_setup_instruments.result:
  Updated test results after removing global
  COND_global_read_lock condition variable.
mysql-test/suite/perfschema/r/func_file_io.result:
  Ensure that this test doesn't affect subsequent tests.
  At the end of its execution enable back P_S instrumentation
  which this test disables at some point.
mysql-test/suite/perfschema/r/func_mutex.result:
  Ensure that this test doesn't affect subsequent tests.
  At the end of its execution enable back P_S instrumentation
  which this test disables at some point.
mysql-test/suite/perfschema/r/global_read_lock.result:
  Adjusted test case to take into account that new GRL
  implementation is based on MDL.
mysql-test/suite/perfschema/r/server_init.result:
  Adjusted test case after replacing custom global read
  lock implementation with one based on MDL and replacing
  LOCK_event_metadata mutex with metadata lock.
mysql-test/suite/perfschema/t/func_file_io.test:
  Ensure that this test doesn't affect subsequent tests.
  At the end of its execution enable back P_S instrumentation
  which this test disables at some point.
mysql-test/suite/perfschema/t/func_mutex.test:
  Ensure that this test doesn't affect subsequent tests.
  At the end of its execution enable back P_S instrumentation
  which this test disables at some point.
mysql-test/suite/perfschema/t/global_read_lock.test:
  Adjusted test case to take into account that new GRL
  implementation is based on MDL.
mysql-test/suite/perfschema/t/server_init.test:
  Adjusted test case after replacing custom global read
  lock implementation with one based on MDL and replacing
  LOCK_event_metadata mutex with metadata lock.
mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result:
  Updated test results after prohibiting event DDL under
  LOCK TABLES.
mysql-test/t/delayed.test:
  Added test coverage for scenario which triggered assert in
  metadata locking subsystem.
mysql-test/t/events_2.test:
  Updated test case after prohibiting event DDL operations
  under LOCK TABLES.
mysql-test/t/flush.test:
  Added test coverage for bug #57006 "Deadlock between HANDLER
  and FLUSH TABLES WITH READ LOCK".
mysql-test/t/flush_block_commit.test:
  Adjusted test case after changing thread state name which
  is used when COMMIT waits for FLUSH TABLES WITH READ LOCK
  from "Waiting for release of readlock" to "Waiting for commit
  lock".
mysql-test/t/flush_block_commit_notembedded.test:
  Adjusted test case after changing thread state name which is
  used when DML waits for FLUSH TABLES WITH READ LOCK. Now we
  use "Waiting for global read lock" in this case.
mysql-test/t/flush_read_lock.test:
  Added test coverage for various aspects of FLUSH TABLES WITH
  READ LOCK functionality.
mysql-test/t/flush_read_lock_kill-master.opt:
  We no longer need to use make_global_read_lock_block_commit_loop
  debug tag in this test. Instead we rely on an appropriate
  debug_sync point in MDL code.
mysql-test/t/flush_read_lock_kill.test:
  Adjusted test case after replacing custom global read lock
  implementation with one based on metadata locks. Use new
  debug_sync point. Do not disable concurrent inserts as now
  InnoDB we always use InnoDB table.
mysql-test/t/lock_multi.test:
  Adjusted test case after changing thread state names which
  are used when DML or DDL waits for FLUSH TABLES WITH READ
  LOCK to "Waiting for global read lock".
mysql-test/t/mdl_sync.test:
  Adjusted test case after replacing custom global read lock
  implementation with one based on metadata locks. Replaced
  usage of GRL-specific debug_sync's with appropriate sync
  points in MDL subsystem. Updated thread state names which
  are used when DDL waits for FTWRL.
mysql-test/t/trigger_notembedded.test:
  Adjusted test case after changing thread state names which
  are used when DML or DDL waits for FLUSH TABLES WITH READ
  LOCK to "Waiting for global read lock".
sql/event_data_objects.cc:
  Removed Event_queue_element::status/last_executed_changed
  members and Event_queue_element::update_timing_fields()
  method. We no longer use this class for updating mysql.events
  once event is chosen for execution. Accesses to instances of
  this class in scheduler thread require protection by
  Event_queue::LOCK_event_queue mutex and we try to avoid
  updating table while holding this lock.
sql/event_data_objects.h:
  Removed Event_queue_element::status/last_executed_changed
  members and Event_queue_element::update_timing_fields()
  method. We no longer use this class for updating mysql.events
  once event is chosen for execution. Accesses to instances of
  this class in scheduler thread require protection by
  Event_queue::LOCK_event_queue mutex and we try to avoid
  updating table while holding this lock.
sql/event_db_repository.cc:
  - Changed Event_db_repository methods to not release all
    metadata locks once they are done updating mysql.events
    table. This allows to keep metadata lock protecting
    against GRL and lock protecting particular event around
    until corresponding DDL statement is written to the binary
    log.
  - Removed logic for conditional update of "status" and
    "last_executed" fields from update_timing_fields_for_event()
    method. In the only case when this method is called now
    "last_executed" is always modified and tracking change
    of "status" is too much hassle.
sql/event_db_repository.h:
  Removed logic for conditional update of "status" and
  "last_executed" fields from Event_db_repository::
  update_timing_fields_for_event() method.
  In the only case when this method is called now "last_executed"
  is always modified and tracking change of "status" field is
  too much hassle.
sql/event_queue.cc:
  Changed event scheduler code not to update mysql.events
  table while holding Event_queue::LOCK_event_queue mutex.
  Doing so led to a deadlock with a new GRL implementation.
  This deadlock didn't occur with old implementation due to
  fact that code acquiring protection against GRL ignored
  pending GRL requests (which lead to GRL starvation).
  One of goals of new implementation is to disallow GRL
  starvation and so we have to solve problem with this
  deadlock in a different way.
sql/events.cc:
  Changed methods of Events class to acquire protection
  against GRL while perfoming DDL statement and keep it
  until statement is written to the binary log.
  Unfortunately this step together with new GRL implementation
  exposed deadlock involving Events::LOCK_event_metadata
  and GRL. To solve it Events::LOCK_event_metadata mutex was
  replaced with a metadata lock on event. As a side-effect
  events DDL has to be prohibited under LOCK TABLES even in
  cases when mysql.events table was explicitly locked for
  write.
sql/events.h:
  Replaced Events::LOCK_event_metadata mutex with a metadata
  lock on event.
sql/ha_ndbcluster.cc:
  Updated code after replacing custom global read lock
  implementation with one based on MDL. Since MDL subsystem
  should now be able to detect deadlocks involving metadata
  locks and GRL there is no need for special handling of
  active GRL.
sql/handler.cc:
  Replaced custom implementation of global read lock with
  one based on metadata locks. Consequently when doing
  commit instead of calling method of Global_read_lock
  class to acquire protection against GRL we simply acquire
  IX in COMMIT namespace.
sql/lock.cc:
  Replaced custom implementation of global read lock with
  one based on metadata locks. This step allows to expose
  wait for GRL to deadlock detector of MDL subsystem and
  thus succesfully resolve deadlocks similar to one behind
  bug #57006 "Deadlock between HANDLER and FLUSH TABLES
  WITH READ LOCK". It also solves problem with GRL starvation
  described in bug #54673 "It takes too long to get readlock
  for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used
  by GRL give preference to FTWRL statement instead of DML
  statements (if needed in future this can be changed to
  fair scheduling).
  
  Similar to old implementation of acquisition of GRL is
  two-step. During the first step we block all concurrent
  DML and DDL statements by acquiring global S metadata lock
  (each DML and DDL statement acquires global IX lock for
  its duration). During the second step we block commits by
  acquiring global S lock in COMMIT namespace (commit code
  acquires global IX lock in this namespace).
  
  Note that unlike in old implementation acquisition of
  protection against GRL in DML and DDL is semi-automatic.
  We assume that any statement which should be blocked by GRL
  will either open and acquires write-lock on tables or acquires
  metadata locks on objects it is going to modify. For any such
  statement global IX metadata lock is automatically acquired
  for its duration.
  
  To support this change:
  - Global_read_lock::lock/unlock_global_read_lock and
    make_global_read_lock_block_commit methods were changed
    accordingly.
  - Global_read_lock::wait_if_global_read_lock() and
    start_waiting_global_read_lock() methods were dropped.
    It is now responsibility of code acquiring metadata locks
    opening tables to acquire protection against GRL by
    explicitly taking global IX lock with statement duration.
  - Global variables, mutex and condition variable used by
    old implementation was removed.
  - lock_routine_name() was changed to use statement duration for
    its global IX lock. It was also renamed to lock_object_name()
    as it now also used to take metadata locks on events.
  - Global_read_lock::set_explicit_lock_duration() was added which
    allows not to release locks used for GRL when leaving prelocked
    mode.
sql/lock.h:
  - Renamed lock_routine_name() to lock_object_name() and changed
    its signature to allow its usage for events.
  - Removed broadcast_refresh() function. It is no longer needed
    with new GRL implementation.
sql/log_event.cc:
  Release metadata locks with statement duration at the end
  of processing legacy event for LOAD DATA. This ensures that
  replication thread processing such event properly releases
  its protection against global read lock.
sql/mdl.cc:
  Changed MDL subsystem to support new MDL-based implementation
  of global read lock.
  
  Added COMMIT and EVENTS namespaces for metadata locks. Changed
  thread state name for GLOBAL namespace to "Waiting for global
  read lock".
  
  Optimized MDL_map::find_or_insert() method to avoid taking
  m_mutex mutex when looking up MDL_lock objects for GLOBAL
  or COMMIT namespaces. We keep pre-created MDL_lock objects
  for these namespaces around and simply return pointers to
  these global objects when needed.
  
  Changed MDL_lock/MDL_scoped_lock to properly handle
  notification of insert delayed handler threads when FTWRL
  takes global S lock.
  
  Introduced concept of lock duration. In addition to locks with
  transaction duration which work in the way which is similar to
  how locks worked before (i.e. they are released at the end of
  transaction), locks with statement and explicit duration were
  introduced.
  Locks with statement duration are automatically released at the
  end of statement. Locks with explicit duration require explicit
  release and obsolete concept of transactional sentinel.
  
  * Changed MDL_request and MDL_ticket classes to support notion
    of duration.
  * Changed MDL_context to keep locks with different duration in
    different lists. Changed code handling ticket list to take
    this into account.
  * Changed methods responsible for releasing locks to take into
    account duration of tickets. Particularly public
    MDL_context::release_lock() method now only can release
    tickets with explicit duration (there is still internal
    method which allows to specify duration). To release locks
    with statement or transaction duration one have to use
    release_statement/transactional_locks() methods.
  * Concept of savepoint for MDL subsystem now has to take into
    account locks with statement duration. Consequently
    MDL_savepoint class was introduced and methods working with
    savepoints were updated accordingly.
  * Added methods which allow to set duration for one or all
    locks in the context.
sql/mdl.h:
  Changed MDL subsystem to support new MDL-based implementation
  of global read lock.
  
  Added COMMIT and EVENTS namespaces for metadata locks.
  
  Introduced concept of lock duration. In addition to locks with
  transaction duration which work in the way which is similar to
  how locks worked before (i.e. they are released at the end of
  transaction), locks with statement and explicit duration were
  introduced.
  Locks with statement duration are automatically released at the
  end of statement. Locks with explicit duration require explicit
  release and obsolete concept of transactional sentinel.
  
  * Changed MDL_request and MDL_ticket classes to support notion
    of duration.
  * Changed MDL_context to keep locks with different duration in
    different lists. Changed code handling ticket list to take
    this into account.
  * Changed methods responsible for releasing locks to take into
    account duration of tickets. Particularly public
    MDL_context::release_lock() method now only can release
    tickets with explicit duration (there is still internal
    method which allows to specify duration). To release locks
    with statement or transaction duration one have to use
    release_statement/transactional_locks() methods.
  * Concept of savepoint for MDL subsystem now has to take into
    account locks with statement duration. Consequently
    MDL_savepoint class was introduced and methods working with
    savepoints were updated accordingly.
  * Added methods which allow to set duration for one or all
    locks in the context.
sql/mysqld.cc:
  Removed global mutex and condition variables which were used
  by old implementation of GRL.
  Also we no longer need to initialize Events::LOCK_event_metadata
  mutex as it was replaced with metadata locks on events.
sql/mysqld.h:
  Removed global variable, mutex and condition variables which
  were used by old implementation of GRL.
sql/rpl_rli.cc:
  When slave thread closes tables which were open for handling
  of RBR events ensure that it releases global IX lock which
  was acquired as protection against GRL.
sql/sp.cc:
  Adjusted code to the new signature of lock_object/routine_name(),
  to the fact that one now needs specify duration of lock when
  initializing MDL_request and to the fact that savepoints for MDL
  subsystem are now represented by MDL_savepoint class.
sql/sp_head.cc:
  Ensure that statements in stored procedures release statement
  metadata locks and thus release their protectiong against GRL
  in proper moment in time.
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/sql_admin.cc:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/sql_base.cc:
  - Implemented support for new approach to acquiring protection
    against global read lock. We no longer acquire such protection
    explicitly on the basis of statement flags. Instead we always
    rely on code which is responsible for acquiring metadata locks
    on object to be changed acquiring this protection. This is
    achieved by acquiring global IX metadata lock with statement
    duration. Code doing this also responsible for checking that
    current connection has no active GRL by calling an
    Global_read_lock::can_acquire_protection() method.
    Changed code in open_table() and lock_table_names()
    accordingly.
    Note that as result of this change DDL and DML on temporary
    tables is always compatible with GRL (before it was
    incompatible in some cases and compatible in other cases).
  - To speed-up code acquiring protection against GRL introduced
    m_has_protection_against_grl member in Open_table_context
    class. It indicates that protection was already acquired
    sometime during open_tables() execution and new attempts
    can be skipped.
  - Thanks to new GRL implementation calls to broadcast_refresh()
    became unnecessary and were removed.
  - Adjusted code to the fact that one now needs specify duration
    of lock when initializing MDL_request and to the fact that
    savepoints for MDL subsystem are now represented by
    MDL_savepoint class.
sql/sql_base.h:
  Adjusted code to the fact that savepoints for MDL subsystem are
  now represented by MDL_savepoint class.
  Also introduced Open_table_context::m_has_protection_against_grl
  member which allows to avoid acquiring protection against GRL
  while opening tables if such protection was already acquired.
sql/sql_class.cc:
  Changed THD::leave_locked_tables_mode() after transactional
  sentinel for metadata locks was obsoleted by introduction of
  locks with explicit duration.
sql/sql_class.h:
  - Adjusted code to the fact that savepoints for MDL subsystem
    are now represented by MDL_savepoint class.
  - Changed Global_read_lock class according to changes in
    global read lock implementation:
    * wait_if_global_read_lock and start_waiting_global_read_lock
      are now gone. Instead code needing protection against GRL
      has to acquire global IX metadata lock with statement
      duration itself. To help it new can_acquire_protection()
      was introduced. Also as result of the above change
      m_protection_count member is gone too.
    * Added m_mdl_blocks_commits_lock member to store metadata
      lock blocking commits.
    * Adjusted code to the fact that concept of transactional
      sentinel was obsoleted by concept of lock duration.
  - Removed CF_PROTECT_AGAINST_GRL flag as it is no longer
    necessary. New GRL implementation acquires protection
    against global read lock automagically when statement
    acquires metadata locks on tables or other objects it
    is going to change.
sql/sql_db.cc:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/sql_handler.cc:
  Removed call to broadcast_refresh() function. It is no longer
  needed with new GRL implementation.
  Adjusted code after introducing duration concept for metadata
  locks. Particularly to the fact transactional sentinel was
  replaced with explicit duration.
sql/sql_handler.h:
  Renamed mysql_ha_move_tickets_after_trans_sentinel() to
  mysql_ha_set_explicit_lock_duration() after transactional
  sentinel was obsoleted by locks with explicit duration.
sql/sql_insert.cc:
  Adjusted code handling delaying inserts after switching to
  new GRL implementation. Now connection thread initiating
  delayed insert has to acquire global IX lock in addition
  to metadata lock on table being inserted into. This IX lock
  protects against GRL and similarly to SW lock on table being
  inserted into has to be passed to handler thread in order to
  avoid deadlocks.
sql/sql_lex.cc:
  LEX::protect_against_global_read_lock member is no longer
  necessary since protection against GRL is automatically
  taken by code acquiring metadata locks/opening tables.
sql/sql_lex.h:
  LEX::protect_against_global_read_lock member is no longer
  necessary since protection against GRL is automatically
  taken by code acquiring metadata locks/opening tables.
sql/sql_parse.cc:
  - Implemented support for new approach to acquiring protection
    against global read lock. We no longer acquire such protection
    explicitly on the basis of statement flags. Instead we always
    rely on code which is responsible for acquiring metadata locks
    on object to be changed acquiring this protection. This is
    achieved by acquiring global IX metadata lock with statement
    duration. This lock is automatically released at the end of
    statement execution.
  - Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not
    to release metadata locks and thus protection against of GRL
    in the middle of statement execution.
  - Adjusted code to the fact that one now needs specify duration
    of lock when initializing MDL_request and to the fact that
    savepoints for MDL subsystem are now represented by
    MDL_savepoint class.
sql/sql_prepare.cc:
  Adjusted code to the to the fact that savepoints for MDL
  subsystem are now represented by MDL_savepoint class.
sql/sql_rename.cc:
  With new GRL implementation there is no need to explicitly
  acquire protection against GRL before renaming tables.
  This happens automatically in code which acquires metadata
  locks on tables being renamed.
sql/sql_show.cc:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request and to the fact that
  savepoints for MDL subsystem are now represented by
  MDL_savepoint class.
sql/sql_table.cc:
  - With new GRL implementation there is no need to explicitly
    acquire protection against GRL before dropping tables.
    This happens automatically in code which acquires metadata
    locks on tables being dropped.
  - Changed mysql_alter_table() not to release lock on new table
    name explicitly and to rely on automatic release of locks
    at the end of statement instead. This was necessary since
    now MDL_context::release_lock() is supported only for locks
    for explicit duration.
sql/sql_trigger.cc:
  With new GRL implementation there is no need to explicitly
  acquire protection against GRL before changing table triggers.
  This happens automatically in code which acquires metadata
  locks on tables which triggers are to be changed.
sql/sql_update.cc:
  Fix bug exposed by GRL testing. During prepare phase acquire
  only S metadata locks instead of SW locks to keep prepare of
  multi-UPDATE compatible with concurrent LOCK TABLES WRITE
  and global read lock.
sql/sql_view.cc:
  With new GRL implementation there is no need to explicitly
  acquire protection against GRL before creating view.
  This happens automatically in code which acquires metadata
  lock on view to be created.
sql/sql_yacc.yy:
  LEX::protect_against_global_read_lock member is no longer
  necessary since protection against GRL is automatically
  taken by code acquiring metadata locks/opening tables.
sql/table.cc:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/table.h:
  Adjusted code to the fact that one now needs specify duration
  of lock when initializing MDL_request.
sql/transaction.cc:
  Replaced custom implementation of global read lock with
  one based on metadata locks. Consequently when doing
  commit instead of calling method of Global_read_lock
  class to acquire protection against GRL we simply acquire
  IX in COMMIT namespace.
  Also adjusted code to the fact that MDL savepoint is now
  represented by MDL_savepoint class.

> ------------------------------------------------------------
> revno: 3452.1.12
> revision-id: davi.arnaut@oracle.com-20100730121710-sc068t4d2f1c2gi9
> parent: dao-gang.qu@sun.com-20100730035934-8in8err1b1rqu72y
> committer: Davi Arnaut <davi.arnaut@oracle.com>
> branch nick: mysql-5.1-bugteam
> timestamp: Fri 2010-07-30 09:17:10 -0300
> message:
>   Bug#54041: MySQL 5.0.92 fails when tests from Connector/C suite run
>   
>   Fix a regression (due to a typo) which caused spurious incorrect
>   argument errors for long data stream parameters if all forms of
>   logging were disabled (binary, general and slow logs).

In case of outer join and emtpy WHERE conditon
'always true' condition is created for WHERE clasue.
Later in mysql_select() original SELECT_LEX WHERE
condition is overwritten with created cond.
However SELECT_LEX condition is also used as inital
condition in mysql_select()->JOIN::prepare().
On second execution of PS modified SELECT_LEX condition
is taken and it leads to crash.
The fix is to restore original SELECT_LEX condition
(set to NULL if original cond is NULL) in
 reinit_stmt_before_use().
HAVING clause is fixed too for safety reason
(no test case as I did not manage to think out
 appropriate example).


mysql-test/r/ps.result:
  test case
mysql-test/t/ps.test:
  test case
sql/sql_prepare.cc:
  restore original SELECT_LEX condition
  (set to NULL if original cond is NULL) in
   reinit_stmt_before_use()

        'CREATE TABLE IF NOT EXISTS ... SELECT' behaviour
BUG#47132, BUG#47442, BUG49494, BUG#23992 and BUG#48814 will disappear
automatically after the this patch.
BUG#55617 is fixed by this patch too.
            
This is the 5.5 part.
It implements:
- 'CREATE TABLE IF NOT EXISTS ... SELECT' statement will not insert
  anything and binlog anything if the table already exists.
  It only generate a warning that table already exists.
- A couple of test cases for the behavior changing.

Fix a regression (due to a typo) which caused spurious incorrect
argument errors for long data stream parameters if all forms of
logging were disabled (binary, general and slow logs).

sql/sql_prepare.cc:
  Add a missing logical NOT operator.

Fix a regression (due to a typo) which caused spurious incorrect
argument errors for long data stream parameters if all forms of
logging were disabled (binary, general and slow logs).

mysql-test/t/mysql_client_test.test:
  Save the status of the slow_log.
sql/sql_prepare.cc:
  Add a missing logical NOT operator.
tests/mysql_client_test.c:
  Disable all query logs when running C tests. Fixes a omission
  when, slow log should have been disabled too.
  
  Run test case for Bug#54041 with query logs enabled and disabled.

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.

This patch also fixes Bug#55452 "SET PASSWORD is
replicated twice in RBR mode".

The goal of this patch is to remove the release of 
metadata locks from close_thread_tables().
This is necessary to not mistakenly release
the locks in the course of a multi-step
operation that involves multiple close_thread_tables()
or close_tables_for_reopen().

On the same token, move statement commit outside 
close_thread_tables().

Other cleanups:
Cleanup COM_FIELD_LIST.
Don't call close_thread_tables() in COM_SHUTDOWN -- there
are no open tables there that can be closed (we leave
the locked tables mode in THD destructor, and this
close_thread_tables() won't leave it anyway).

Make open_and_lock_tables() and open_and_lock_tables_derived()
call close_thread_tables() upon failure.
Remove the calls to close_thread_tables() that are now
unnecessary.

Simplify the back off condition in Open_table_context.

Streamline metadata lock handling in LOCK TABLES 
implementation.

Add asserts to ensure correct life cycle of 
statement transaction in a session.

Remove a piece of dead code that has also become redundant
after the fix for Bug 37521.

mysql-test/r/variables.result:
  Update results: set @@autocommit and statement transaction/
  prelocked mode.
mysql-test/r/view.result:
  A harmless change in CHECK TABLE <view> status for a broken view.
  If previously a failure to prelock all functions used in a view 
  would leave the connection in LTM_PRELOCKED mode, now we call
  close_thread_tables() from open_and_lock_tables()
  and leave prelocked mode, thus some check in mysql_admin_table() that
  works only in prelocked/locked tables mode is no longer activated.
mysql-test/suite/rpl/r/rpl_row_implicit_commit_binlog.result:
  Fixed Bug#55452 "SET PASSWORD is replicated twice in
  RBR mode": extra binlog events are gone from the
  binary log.
mysql-test/t/variables.test:
  Add a test case: set autocommit and statement transaction/prelocked
  mode.
sql/event_data_objects.cc:
  Simplify code in Event_job_data::execute().
  Move sp_head memory management to lex_end().
sql/event_db_repository.cc:
  Move the release of metadata locks outside
  close_thread_tables().
  Make sure we call close_thread_tables() when
  open_and_lock_tables() fails and remove extra
  code from the events data dictionary.
  Use close_mysql_tables(), a new internal
  function to properly close mysql.* tables
  in the data dictionary.
  Contract Event_db_repository::drop_events_by_field,
  drop_schema_events into one function.
  When dropping all events in a schema,
  make sure we don't mistakenly release all
  locks acquired by DROP DATABASE. These
  include locks on the database name
  and the global intention exclusive
  metadata lock.
sql/event_db_repository.h:
  Function open_event_table() does not require an instance 
  of Event_db_repository.
sql/events.cc:
  Use close_mysql_tables() instead of close_thread_tables()
  to bootstrap events, since the latter no longer
  releases metadata locks.
sql/ha_ndbcluster.cc:
  - mysql_rm_table_part2 no longer releases
  acquired metadata locks. Do it in the caller.
sql/ha_ndbcluster_binlog.cc:
  Deploy the new protocol for closing thread
  tables in run_query() and ndb_binlog_index
  code.
sql/handler.cc:
  Assert that we never call ha_commit_trans/
  ha_rollback_trans in sub-statement, which
  is now the case.
sql/handler.h:
  Add an accessor to check whether THD_TRANS object
  is empty (has no transaction started).
sql/log.cc:
  Update a comment.
sql/log_event.cc:
  Since now we commit/rollback statement transaction in 
  mysql_execute_command(), we need a mechanism to communicate
  from Query_log_event::do_apply_event() to mysql_execute_command()
  that the statement transaction should be rolled back, not committed.
  Ideally it would be a virtual method of THD. I hesitate
  to make THD a virtual base class in this already large patch.
  Use a thd->variables.option_bits for now.
  
  Remove a call to close_thread_tables() from the slave IO
  thread. It doesn't open any tables, and the protocol
  for closing thread tables is more complicated now.
  
  Make sure we properly close thread tables, however, 
  in Load_data_log_event, which doesn't
  follow the standard server execution procedure
  with mysql_execute_command().
  @todo: this piece should use Server_runnable
  framework instead.
  Remove an unnecessary call to mysql_unlock_tables().
sql/rpl_rli.cc:
  Update Relay_log_info::slave_close_thread_tables()
  to follow the new close protocol.
sql/set_var.cc:
  Remove an unused header.
sql/slave.cc:
  Remove an unnecessary call to
  close_thread_tables().
sql/sp.cc:
  Remove unnecessary calls to close_thread_tables()
  from SP DDL implementation. The tables will
  be closed by the caller, in mysql_execute_command().
  When dropping all routines in a database, make sure
  to not mistakenly drop all metadata locks acquired
  so far, they include the scoped lock on the schema.
sql/sp_head.cc:
  Correct the protocol that closes thread tables
  in an SP instruction.
  Clear lex->sphead before cleaning up lex
  with lex_end to make sure that we don't
  delete the sphead twice. It's considered
  to be "cleaner" and more in line with
  future changes than calling delete lex->sphead
  in other places that cleanup the lex.
sql/sp_head.h:
  When destroying m_lex_keeper of an instruction,
  don't delete the sphead that all lex objects
  share. 
  @todo: don't store a reference to routine's sp_head
  instance in instruction's lex.
sql/sql_acl.cc:
  Don't call close_thread_tables() where the caller will
  do that for us.
  Fix Bug#55452 "SET PASSWORD is replicated twice in RBR 
  mode" by disabling RBR replication in change_password()
  function.
  Use close_mysql_tables() in bootstrap and ACL reload
  code to make sure we release all metadata locks.
sql/sql_base.cc:
  This is the main part of the patch:
  - remove manipulation with thd->transaction
  and thd->mdl_context from close_thread_tables().
  Now this function is only responsible for closing
  tables, nothing else.
  This is necessary to be able to easily use
  close_thread_tables() in procedures, that
  involve multiple open/close tables, which all
  need to be protected continuously by metadata
  locks.
  Add asserts ensuring that TABLE object
  is only used when is protected by a metadata lock.
  Simplify the back off condition of Open_table_context,
  we no longer need to look at the autocommit mode.
  Make open_and_lock_tables() and open_normal_and_derived_tables()
  close thread tables and release metadata locks acquired so-far 
  upon failure. This simplifies their usage.
  Implement close_mysql_tables().
sql/sql_base.h:
  Add declaration for close_mysql_tables().
sql/sql_class.cc:
  Remove a piece of dead code that has also become redundant
  after the fix for Bug 37521.
  The code became dead when my_eof() was made a non-protocol method,
  but a method that merely modifies the diagnostics area.
  The code became redundant with the fix for Bug#37521, when 
  we started to cal close_thread_tables() before
  Protocol::end_statement().
sql/sql_do.cc:
  Do nothing in DO if inside a substatement
  (the assert moved out of trans_rollback_stmt).
sql/sql_handler.cc:
  Add comments.
sql/sql_insert.cc:
  Remove dead code. 
  Release metadata locks explicitly at the
  end of the delayed insert thread.
sql/sql_lex.cc:
  Add destruction of lex->sphead to lex_end(),
  lex "reset" method called at the end of each statement.
sql/sql_parse.cc:
  Move close_thread_tables() and other related
  cleanups to mysql_execute_command()
  from dispatch_command(). This has become
  possible after the fix for Bug#37521.
  Mark federated SERVER statements as DDL.
  
  Next step: make sure that we don't store
  eof packet in the query cache, and move
  the query cache code outside mysql_parse.
  
  Brush up the code of COM_FIELD_LIST.
  Remove unnecessary calls to close_thread_tables().
  
  When killing a query, don't report "OK"
  if it was a suicide.
sql/sql_parse.h:
  Remove declaration of a function that is now static.
sql/sql_partition.cc:
  Remove an unnecessary call to close_thread_tables().
sql/sql_plugin.cc:
  open_and_lock_tables() will clean up
  after itself after a failure.
  Move close_thread_tables() above
  end: label, and replace with close_mysql_tables(),
  which will also release the metadata lock
  on mysql.plugin.
sql/sql_prepare.cc:
  Now that we no longer release locks in close_thread_tables()
  statement prepare code has become more straightforward.
  Remove the now redundant check for thd->killed() (used
  only by the backup project) from Execute_server_runnable.
  Reorder code to take into account that now mysql_execute_command()
  performs lex->unit.cleanup() and close_thread_tables().
sql/sql_priv.h:
  Add a new option to server options to interact
  between the slave SQL thread and execution
  framework (hack). @todo: use a virtual
  method of class THD instead.
sql/sql_servers.cc:
  Due to Bug 25705 replication of 
  DROP/CREATE/ALTER SERVER is broken.
  Make sure at least we do not attempt to 
  replicate these statements using RBR,
  as this violates the assert in close_mysql_tables().
sql/sql_table.cc:
  Do not release metadata locks in mysql_rm_table_part2,
  this is done by the caller.
  Do not call close_thread_tables() in mysql_create_table(),
  this is done by the caller. 
  Fix a bug in DROP TABLE under LOCK TABLES when,
  upon error in wait_while_table_is_used() we would mistakenly
  release the metadata lock on a non-dropped table.
  Explicitly release metadata locks when doing an implicit
  commit.
sql/sql_trigger.cc:
  Now that we delete lex->sphead in lex_end(),
  zero the trigger's sphead in lex after loading
  the trigger, to avoid double deletion.
sql/sql_udf.cc:
  Use close_mysql_tables() instead of close_thread_tables().
sql/sys_vars.cc:
  Remove code added in scope of WL#4284 which would
  break when we perform set @@session.autocommit along
  with setting other variables and using tables or functions.
  A test case added to variables.test.
sql/transaction.cc:
  Add asserts.
sql/tztime.cc:
  Use close_mysql_tables() rather than close_thread_tables().

to write into a closed socket

sql/protocol.cc:
  Protocol::flush modified: set thd->main_da.can_overwrite_status= TRUE
  before call to net_flush() in order to prevent crash on assert in case
  of socket write failure, reset it to FALSE when net_flush() returned;
  Protocol::send_fields modified: return from method with error if call to
  my_net_write(), proto.write() or write_eof_packet() failed.
sql/sql_cache.cc:
  Query_cache::send_result_to_client modified: call to
  thd->main_da.disable_status() only if write to socket
  was successful.
sql/sql_cursor.cc:
  Materialized_cursor::fetch modified: leave method if call to
  result->send_data() failed.
sql/sql_prepare.cc:
  send_prep_stmt() modified: call to thd->main_da.disable_status()
  only if thd->protocol_text.send_fields() completed successfully.

The problem was that a user could supply supply data in chunks
via the COM_STMT_SEND_LONG_DATA command to prepared statement
parameter other than of type TEXT or BLOB. This posed a problem
since other parameter types aren't setup to handle long data,
which would lead to a crash when attempting to use the supplied
data.

Given that long data can be supplied at any stage of a prepared
statement, coupled with the fact that the type of a parameter
marker might change between consecutive executions, the solution
is to validate at execution time each parameter marker for which
a data stream was provided. If the parameter type is not TEXT or
BLOB (that is, if the type is not able to handle a data stream),
a error is returned.

sql/sql_prepare.cc:
  Before converting the parameter data stream, check the type
  compatibility.
tests/mysql_client_test.c:
  Add test case.

In Prepared_statement::prepare() bail out as soon as
parser_state.init() fails, trying to continue leads to crashes.

            strict aliasing violations.

One somewhat major source of strict-aliasing violations and
related warnings is the SQL_LIST structure. For example,
consider its member function `link_in_list` which takes
a pointer to pointer of type T (any type) as a pointer to
pointer to unsigned char. Dereferencing this pointer, which
is done to reset the next field, violates strict-aliasing
rules and might cause problems for surrounding code that
uses the next field of the object being added to the list.

The solution is to use templates to parametrize the SQL_LIST
structure in order to deference the pointers with compatible
types. As a side bonus, it becomes possible to remove quite
a few casts related to acessing data members of SQL_LIST.

sql/handler.h:
  Use the appropriate template type argument.
sql/item.cc:
  Remove now-unnecessary cast.
sql/item_subselect.cc:
  Remove now-unnecessary casts.
sql/item_sum.cc:
  Use the appropriate template type argument.
  Remove now-unnecessary cast.
sql/mysql_priv.h:
  Move SQL_LIST structure to sql_list.h
  Use the appropriate template type argument.
sql/sp.cc:
  Remove now-unnecessary casts.
sql/sql_delete.cc:
  Use the appropriate template type argument.
  Remove now-unnecessary casts.
sql/sql_derived.cc:
  Remove now-unnecessary casts.
sql/sql_lex.cc:
  Remove now-unnecessary casts.
sql/sql_lex.h:
  SQL_LIST now takes a template type argument which must
  match the type of the elements of the list. Use forward
  declaration when the type is not available, it is used
  in pointers anyway.
sql/sql_list.h:
  Rename SQL_LIST to SQL_I_List. The template parameter is
  the type of object that is stored in the list.
sql/sql_olap.cc:
  Remove now-unnecessary casts.
sql/sql_parse.cc:
  Remove now-unnecessary casts.
sql/sql_prepare.cc:
  Remove now-unnecessary casts.
sql/sql_select.cc:
  Remove now-unnecessary casts.
sql/sql_show.cc:
  Remove now-unnecessary casts.
sql/sql_table.cc:
  Remove now-unnecessary casts.
sql/sql_trigger.cc:
  Remove now-unnecessary casts.
sql/sql_union.cc:
  Remove now-unnecessary casts.
sql/sql_update.cc:
  Remove now-unnecessary casts.
sql/sql_view.cc:
  Remove now-unnecessary casts.
sql/sql_yacc.yy:
  Remove now-unnecessary casts.
storage/myisammrg/ha_myisammrg.cc:
  Remove now-unnecessary casts.

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.

            Item_hex_string::Item_hex_string

The status of memory allocation in the Lex_input_stream (called
from the Parser_state constructor) was not checked which led to
a parser crash in case of the out-of-memory error.

The solution is to introduce new init() member function in
Parser_state and Lex_input_stream so that status of memory
allocation can be returned to the caller.

mysql-test/r/error_simulation.result:
  Added a test case for bug #42064.
mysql-test/t/error_simulation.test:
  Added a test case for bug #42064.
mysys/my_alloc.c:
  Added error injection code for the regression test.
mysys/my_malloc.c:
  Added error injection code for the regression test.
mysys/safemalloc.c:
  Added error injection code for the regression test.
sql/event_data_objects.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/mysqld.cc:
  Added error injection code for the regression test.
sql/sp.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_lex.cc:
  Moved memory allocation from constructor to the separate init()
  member function.
  Added error injection code for the regression test.
sql/sql_lex.h:
  Moved memory allocation from constructor to the separate init()
  member function.
sql/sql_parse.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_partition.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_prepare.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_trigger.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures.
sql/sql_view.cc:
  Use the new init() member function of Parser_state and check
  its return value to handle memory allocation failures..
sql/thr_malloc.cc:
  Added error injection code for the regression test.

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().

Fixes a bug where bool* was used as an argument to a function where the parameter
was of type bool.

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

The problem is introduced by WL#4435 "Support OUT-parameters in 
prepared statements".
When a statement that has out parameters was reprepared,
the reprepare request error was ignored, and an
attempt to send out parameters to the client was made.

Since the out parameter list was not initialized in case
of an error, this attempt led to a crash.

Don't try to send out parameters to the client
if an error occurred in statement execution.

sql/sql_prepare.cc:
  Don't try to send out parameters if error.
tests/mysql_client_test.c:
  Re-enable the test case for Bug#49972.

Add a wait-for graph based deadlock detector to the
MDL subsystem.

Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and
bug #37346 "innodb does not detect deadlock between update and
alter table".

The first bug manifested itself as an unwarranted abort of a
transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER
statement, when this transaction tried to repeat use of a
table, which it has already used in a similar fashion before
ALTER started.

The second bug showed up as a deadlock between table-level
locks and InnoDB row locks, which was "detected" only after
innodb_lock_wait_timeout timeout.

A transaction would start using the table and modify a few
rows.
Then ALTER TABLE would come in, and start copying rows
into a temporary table. Eventually it would stumble on
the modified records and get blocked on a row lock.
The first transaction would try to do more updates, and get
blocked on thr_lock.c lock.
This situation of circular wait would only get resolved
by a timeout.

Both these bugs stemmed from inadequate solutions to the
problem of deadlocks occurring between different
locking subsystems.

In the first case we tried to avoid deadlocks between metadata
locking and table-level locking subsystems, when upgrading shared
metadata lock to exclusive one.
Transactions holding the shared lock on the table and waiting for
some table-level lock used to be aborted too aggressively.

We also allowed ALTER TABLE to start in presence of transactions
that modify the subject table. ALTER TABLE acquires
TL_WRITE_ALLOW_READ lock at start, and that block all writes
against the table (naturally, we don't want any writes to be lost
when switching the old and the new table). TL_WRITE_ALLOW_READ
lock, in turn, would block the started transaction on thr_lock.c
lock, should they do more updates. This, again, lead to the need
to abort such transactions.

The second bug occurred simply because we didn't have any
mechanism to detect deadlocks between the table-level locks
in thr_lock.c and row-level locks in InnoDB, other than
innodb_lock_wait_timeout.

This patch solves both these problems by moving lock conflicts
which are causing these deadlocks into the metadata locking
subsystem, thus making it possible to avoid or detect such
deadlocks inside MDL.

To do this we introduce new type-of-operation-aware metadata
locks, which allow MDL subsystem to know not only the fact that
transaction has used or is going to use some object but also what
kind of operation it has carried out or going to carry out on the
object.

This, along with the addition of a special kind of upgradable
metadata lock, allows ALTER TABLE to wait until all
transactions which has updated the table to go away.
This solves the second issue.
Another special type of upgradable metadata lock is acquired
by LOCK TABLE WRITE. This second lock type allows to solve the
first issue, since abortion of table-level locks in event of
DDL under LOCK TABLES becomes also unnecessary.

Below follows the list of incompatible changes introduced by
this patch:

- From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those
  statements that acquire TL_WRITE_ALLOW_READ lock)
  wait for all transactions which has *updated* the table to
  complete.

- From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE
  (i.e. all statements which acquire TL_WRITE table-level lock) wait
  for all transaction which *updated or read* from the table
  to complete.
  As a consequence, innodb_table_locks=0 option no longer applies
  to LOCK TABLES ... WRITE.

- DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort
  statements or transactions which use tables being dropped or
  renamed, and instead wait for these transactions to complete.

- Since LOCK TABLES WRITE now takes a special metadata lock,
  not compatible with with reads or writes against the subject table
  and transaction-wide, thr_lock.c deadlock avoidance algorithm
  that used to ensure absence of deadlocks between LOCK TABLES
  WRITE and other statements is no longer sufficient, even for
  MyISAM. The wait-for graph based deadlock detector of MDL
  subsystem may sometimes be necessary and is involved. This may
  lead to ER_LOCK_DEADLOCK error produced for multi-statement
  transactions even if these only use MyISAM:

  session 1:         session 2:
  begin;

  update t1 ...      lock table t2 write, t1 write;
                     -- gets a lock on t2, blocks on t1

  update t2 ...
  (ER_LOCK_DEADLOCK)

- Finally,  support of LOW_PRIORITY option for LOCK TABLES ... WRITE
  was abandoned.
  LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same
  priority as the usual LOCK TABLE ... WRITE.
  SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE  in
  the wait queue.

- We do not take upgradable metadata locks on implicitly
  locked tables. So if one has, say, a view v1 that uses
  table t1, and issues:
  LOCK TABLE v1 WRITE;
  FLUSH TABLE t1; -- (or just 'FLUSH TABLES'),
  an error is produced.
  In order to be able to perform DDL on a table under LOCK TABLES,
  the table must be locked explicitly in the LOCK TABLES list.

mysql-test/include/handler.inc:
  Adjusted test case to trigger an execution path on which bug 41110
  "crash with handler command when used concurrently with alter
  table" and bug 41112 "crash in mysql_ha_close_table/get_lock_data
  with alter table" were originally discovered. Left old test case
  which no longer triggers this execution path for the sake of
  coverage.
  Added test coverage for HANDLER SQL statements and type-aware
  metadata locks.
  Added a test for the global shared lock and HANDLER SQL.
  Updated tests to take into account that the old simple deadlock
  detection heuristics was replaced with a graph-based deadlock
  detector.
mysql-test/r/debug_sync.result:
  Updated results (see debug_sync.test).
mysql-test/r/handler_innodb.result:
  Updated results (see handler.inc test).
mysql-test/r/handler_myisam.result:
  Updated results (see handler.inc test).
mysql-test/r/innodb-lock.result:
  Updated results (see innodb-lock.test).
mysql-test/r/innodb_mysql_lock.result:
  Updated results (see innodb_mysql_lock.test).
mysql-test/r/lock.result:
  Updated results (see lock.test).
mysql-test/r/lock_multi.result:
  Updated results (see lock_multi.test).
mysql-test/r/lock_sync.result:
  Updated results (see lock_sync.test).
mysql-test/r/mdl_sync.result:
  Updated results (see mdl_sync.test).
mysql-test/r/sp-threads.result:
  SHOW PROCESSLIST output has changed due to the fact that waiting
  for LOCK TABLES WRITE now happens within metadata locking
  subsystem.
mysql-test/r/truncate_coverage.result:
  Updated results (see truncate_coverage.test).
mysql-test/suite/funcs_1/datadict/processlist_val.inc:
  SELECT FROM I_S.PROCESSLIST output has changed due to fact that
  waiting for LOCK TABLES WRITE now happens within metadata locking
  subsystem.
mysql-test/suite/funcs_1/r/processlist_val_no_prot.result:
  SELECT FROM I_S.PROCESSLIST output has changed due to fact that
  waiting for LOCK TABLES WRITE now happens within metadata locking
  subsystem.
mysql-test/suite/rpl/t/rpl_sp.test:
  Updated to a new SHOW PROCESSLIST state name.
mysql-test/t/debug_sync.test:
  Use LOCK TABLES READ instead of LOCK TABLES WRITE as the latter
  no longer allows to trigger execution path involving waiting on
  thr_lock.c lock and therefore reaching debug sync-point covered
  by this test.
mysql-test/t/innodb-lock.test:
  Adjusted test case to the fact that innodb_table_locks=0 option is
  no longer supported, since LOCK TABLES WRITE handles all its
  conflicts within MDL subsystem.
mysql-test/t/innodb_mysql_lock.test:
  Added test for bug #37346 "innodb does not detect deadlock between
  update and alter table".
mysql-test/t/lock.test:
  Added test coverage which checks the fact that we no longer support
  DDL under LOCK TABLES on tables which were locked implicitly.
  Adjusted existing test cases accordingly.
mysql-test/t/lock_multi.test:
  Added test for bug #46272 "MySQL 5.4.4, new MDL: unnecessary
  deadlock".  Adjusted other test cases to take into account the
  fact that waiting for LOCK TABLES ... WRITE now happens within MDL
  subsystem.
mysql-test/t/lock_sync.test:
  Since LOCK TABLES ... WRITE now takes SNRW metadata lock for
  tables locked explicitly we have to implicitly lock InnoDB tables
  (through view) to trigger the table-level lock conflict between
  TL_WRITE and TL_WRITE_ALLOW_WRITE.
mysql-test/t/mdl_sync.test:
  Added basic test coverage for type-of-operation-aware metadata
  locks. Also covered with tests some use cases involving HANDLER
  statements in which a deadlock could arise.
  Adjusted existing tests to take type-of-operation-aware MDL into
  account.
mysql-test/t/multi_update.test:
  Update to a new SHOW PROCESSLIST state name.
mysql-test/t/truncate_coverage.test:
  Adjusted test case after making LOCK TABLES WRITE to wait until
  transactions that use the table to be locked are completed.
  Updated to the changed name of DEBUG_SYNC point.
sql/handler.cc:
  Global read lock functionality has been
  moved into a class.
sql/lock.cc:
  Global read lock functionality has been
  moved into a class.
  Updated code to use the new MDL API.
sql/mdl.cc:
  Introduced new type-of-operation aware metadata locks.
  To do this:
  - Changed MDL_lock to use one list for waiting requests and one
    list for granted requests. For each list, added a bitmap
    that holds information what lock types a list contains.
    Added a helper class MDL_lock::List to manipulate with granted
    and waited lists while keeping the bitmaps in sync
    with list contents.
  - Changed lock-compatibility functions to use bitmaps that
    define compatibility.
  - Introduced a graph based deadlock detector inspired by
    waiting_threads.c from Maria implementation.
  - Now that we have a deadlock detector, and no longer have
    a global lock to protect individual lock objects, but rather
    use an rw lock per object, removed redundant code for upgrade,
    and the global read lock. Changed the MDL API to
    no longer require the caller to acquire the global
    intention exclusive lock by means of a separate method.
    Removed a few more methods that became redundant.
  - Removed deadlock detection heuristic, it has been made
    obsolete by the deadlock detector.
  - With operation-type-aware metadata locks, MDL subsystem has
    become aware of potential conflicts between DDL and open
    transactions. This made it possible to remove calls to
    mysql_abort_transactions_with_shared_lock() from acquisition
    paths for exclusive lock and lock upgrade. Now we can simply
    wait for these transactions to complete without fear of
    deadlock. Function mysql_lock_abort() has also become
    unnecessary for all conflicting cases except when a DDL
    conflicts with a connection that has an open HANDLER.
sql/mdl.h:
  Introduced new type-of-operation aware metadata locks.
  Introduced a graph based deadlock detector and supporting
  methods.
  Added comments.
  God rid of redundant API calls.
  Renamed m_lt_or_ha_sentinel to m_trans_sentinel,
  since now it guards the global read lock as well as
  LOCK TABLES and HANDLER locks.
sql/mysql_priv.h:
  Moved the global read lock functionality into a
  class.
  Added MYSQL_OPEN_FORCE_SHARED_MDL flag which forces
  open_tables() to take MDL_SHARED on tables instead of
  metadata locks specified in the parser. We use this to
  allow PREPARE run concurrently in presence of
  LOCK TABLES ... WRITE.
  Added signature for find_table_for_mdl_ugprade().
sql/set_var.cc:
  Global read lock functionality has been
  moved into a class.
sql/sp_head.cc:
  When creating TABLE_LIST elements for prelocking or
  system tables set the type of request for metadata
  lock according to the operation that will be performed
  on the table.
sql/sql_base.cc:
  - Updated code to use the new MDL API.
  - In order to avoid locks starvation we take upgradable
    locks all at once. As result implicitly locked tables no
    longer get an upgradable lock. Consequently DDL and FLUSH
    TABLES for such tables is prohibited.
    find_write_locked_table() was replaced by
    find_table_for_mdl_upgrade() function.
    open_table() was adjusted to return TABLE instance with
    upgradable ticket when necessary.
  - We no longer wait for all locks on OT_WAIT back off
    action -- only on the lock that caused the wait
    conflict. Moreover, now we distinguish cases when we
    have to wait due to conflict in MDL and old version
    of table in TDC.
  - Upate mysql_notify_threads_having_share_locks()
    to only abort thr_lock.c waits of threads that
    have open HANDLERs, since lock conflicts with only
    these threads now can lead to deadlocks not detectable
    by the MDL deadlock detector.
  - Remove mysql_abort_transactions_with_shared_locks()
    which is no longer needed.
sql/sql_class.cc:
  Global read lock functionality has been moved into a class.
  Re-arranged code in THD::cleanup() to simplify assert.
sql/sql_class.h:
  Introduced class to incapsulate global read lock
  functionality.
  Now sentinel in MDL subsystem guards the global read lock
  as well as LOCK TABLES and HANDLER locks. Adjusted code
  accordingly.
sql/sql_db.cc:
  Global read lock functionality has been moved into a class.
sql/sql_delete.cc:
  We no longer acquire upgradable metadata locks on tables
  which are locked by LOCK TABLES implicitly. As result
  TRUNCATE TABLE is no longer allowed for such tables.
  Updated code to use the new MDL API.
sql/sql_handler.cc:
  Inform MDL_context about presence of open HANDLERs.
  Since HANLDERs break MDL protocol by acquiring table-level
  lock while holding only S metadata lock on a table MDL
  subsystem should take special care about such contexts (Now
  this is the only case when mysql_lock_abort() is used).
sql/sql_parse.cc:
  Global read lock functionality has been moved into a class.
  Do not take upgradable metadata locks when opening tables
  for CREATE TABLE SELECT as it is not necessary and limits
  concurrency.
  When initializing TABLE_LIST objects before adding them
  to the table list set the type of request for metadata lock
  according to the operation that will be performed on the
  table.
  We no longer acquire upgradable metadata locks on tables
  which are locked by LOCK TABLES implicitly. As result FLUSH
  TABLES is no longer allowed for such tables.
sql/sql_prepare.cc:
  Use MYSQL_OPEN_FORCE_SHARED_MDL flag when opening
  tables during PREPARE. This allows PREPARE to run
  concurrently in presence of LOCK TABLES ... WRITE.
sql/sql_rename.cc:
  Global read lock functionality has been moved into a class.
sql/sql_show.cc:
  Updated code to use the new MDL API.
sql/sql_table.cc:
  Global read lock functionality has been moved into a class.
  We no longer acquire upgradable metadata locks on tables
  which are locked by LOCK TABLES implicitly. As result DROP
  TABLE is no longer allowed for such tables.
  Updated code to use the new MDL API.
sql/sql_trigger.cc:
  Global read lock functionality has been moved into a class.
  We no longer acquire upgradable metadata locks on tables
  which are locked by LOCK TABLES implicitly. As result
  CREATE/DROP TRIGGER is no longer allowed for such tables.
  Updated code to use the new MDL API.
sql/sql_view.cc:
  Global read lock functionality has been moved into a class.
  Fixed results of wrong merge that led to misuse of GLR API.
  CREATE VIEW statement is not a commit statement.
sql/table.cc:
  When resetting TABLE_LIST objects for PS or SP re-execution
  set the type of request for metadata lock according to the
  operation that will be performed on the table. Do the same
  in auxiliary function initializing metadata lock requests
  in a table list.
sql/table.h:
  When initializing TABLE_LIST objects set the type of request
  for metadata lock according to the operation that will be
  performed on the table.
sql/transaction.cc:
  Global read lock functionality has been moved into a class.

'CREATE TABLE IF NOT EXISTS ... SELECT' statement were causing 'CREATE
TEMPORARY TABLE ...' to be written to the binary log in row-based 
mode (a.k.a. RBR), when there was a temporary table with the same name.
Because the 'CREATE TABLE ... SELECT' statement was executed as 
'INSERT ... SELECT' into the temporary table. Since in RBR mode no 
other statements related to temporary tables are written into binary log,
this sometimes broke replication.

This patch changes behavior of 'CREATE TABLE [IF NOT EXISTS] ... SELECT ...'.
it ignores existence of temporary table with the 
same name as table being created and is interpreted
as attempt to create/insert into base table. This makes behavior of
'CREATE TABLE [IF NOT EXISTS] ... SELECT' consistent with
how ordinary 'CREATE TABLE' and 'CREATE TABLE ... LIKE' behave.

Bug#45523 "Objects of class base_ilist should not be copyable".
               
Suppress the compiler-generated public copy constructor
and assignment operator of class base_ilist; instead, implement
move_elements_to() function which transfers ownership of elements
from one list to another.

Part IV: sql instrumentation

3655 Jon Olav Hauglid   2009-10-19
Bug #30977 Concurrent statement using stored function and DROP FUNCTION 
           breaks SBR
Bug #48246 assert in close_thread_table

Implement a fix for:
Bug #41804 purge stored procedure cache causes mysterious hang for many
           minutes
Bug #49972 Crash in prepared statements

The problem was that concurrent execution of DML statements that
use stored functions and DDL statements that drop/modify the same
function might result in incorrect binary log in statement (and
mixed) mode and therefore break replication.

This patch fixes the problem by introducing metadata locking for
stored procedures and functions. This is similar to what is done
in Bug#25144 for views. Procedures and functions now are
locked using metadata locks until the transaction is either
committed or rolled back. This prevents other statements from
modifying the procedure/function while it is being executed. This
provides commit ordering - guaranteeing serializability across
multiple transactions and thus fixes the reported binlog problem.

Note that we do not take locks for top-level CALLs. This means
that procedures called directly are not protected from changes by
simultaneous DDL operations so they are executed at the state they
had at the time of the CALL. By not taking locks for top-level
CALLs, we still allow transactions to be started inside
procedures.

This patch also changes stored procedure cache invalidation.
Upon a change of cache version, we no longer invalidate the entire
cache, but only those routines which we use, only when a statement
is executed that uses them.

This patch also changes the logic of prepared statement validation.
A stored procedure used by a prepared statement is now validated
only once a metadata lock has been acquired. A version mismatch
causes a flush of the obsolete routine from the cache and
statement reprepare.
Incompatible changes:
1) ER_LOCK_DEADLOCK is reported for a transaction trying to access
   a procedure/function that is locked by a DDL operation in
   another connection.

2) Procedure/function DDL operations are now prohibited in LOCK
   TABLES mode as exclusive locks must be taken all at once and
   LOCK TABLES provides no way to specifiy procedures/functions to
   be locked.

Test cases have been added to sp-lock.test and rpl_sp.test.

Work on this bug has very much been a team effort and this patch
includes and is based on contributions from Davi Arnaut, Dmitry
Lenev, Magne Mæhre and Konstantin Osipov.


mysql-test/r/ps_ddl.result:
  Update results (Bug#30977).
mysql-test/r/ps_ddl1.result:
  Update results (Bug#30977).
mysql-test/r/sp-error.result:
  Update results (Bug#30977).
mysql-test/r/sp-lock.result:
  Update results (Bug#30977).
mysql-test/suite/rpl/r/rpl_sp.result:
  Update results (Bug#30977).
mysql-test/suite/rpl/t/rpl_sp.test:
  Add a test case for Bug#30977.
mysql-test/t/ps_ddl.test:
  Update comments. We no longer re-prepare a prepared statement
  when a stored procedure used in top-level CALL is changed.
mysql-test/t/ps_ddl1.test:
  Modifying stored procedure p1 no longer invalidates prepared
  statement "call p1" -- we can re-use the prepared statement
  without invalidation.
mysql-test/t/sp-error.test:
  Use a constant for an error value.
mysql-test/t/sp-lock.test:
  Add test coverage for Bug#30977.
sql/lock.cc:
  Implement lock_routine_name() - a way to acquire an 
  exclusive metadata lock (ex- name-lock) on 
  stored procedure/function.
sql/sp.cc:
  Change semantics of sp_cache_routine() -- now it has an option
  to make sure that the routine that is cached is up to date (has
  the latest sp cache version).
  
  Add sp_cache_invalidate() to sp_drop_routine(), where it was
  missing (a bug!).
  
  Acquire metadata locks for SP DDL (ALTER/CREATE/DROP). This is
  the core of the fix for Bug#30977.
  
  Since caching and cache invalidation scheme was changed, make 
  sure we don't invalidate the SP cache in the middle of a stored
  routine execution. At the same time, make sure we don't access
  stale data due to lack of invalidation. 
  For that, change ALTER FUNCTION/PROCEDURE to not use the cache,
  and SHOW PROCEDURE CODE/SHOW CREATE PROCEDURE/FUNCTION to always
  read an up to date version of the routine from the cache.
sql/sp.h:
  Add a helper wrapper around sp_cache_routine().
sql/sp_cache.cc:
  Implement new sp_cache_version() and sp_cache_flush_obsolete().
  Now we flush stale routines individually, rather than all at once.
sql/sp_cache.h:
  Update signatures of sp_cache_version() and sp_cache_flush_obsolete().
sql/sp_head.cc:
  Add a default initialization of sp_head::m_sp_cache_version.
  Remove a redundant sp_head::create().
sql/sp_head.h:
  Add m_sp_cache_version to sp_head class - we now 
  keep track of every routine in the stored procedure cache, rather than
  of the entire cache.
sql/sql_base.cc:
  Implement prelocking for stored routines. Validate stored
  routines after they were locked.
  Flush obsolete routines upon next access, one by one, not all at once
  (Bug#41804).
  Style fixes.
sql/sql_class.h:
  Rename a Open_table_context method.
sql/sql_parse.cc:
  Make sure stored procedures DDL commits the active transaction 
  (issues an implicit commit before and after).
  Remove sp_head::create(), a pure redundancy.
  Move the semantical check during alter routine inside sp_update_routine() code in order to:
  - avoid using SP cache during update, it may be obsolete.
  - speed up and simplify the update procedure.
  
  Remove sp_cache_flush_obsolete() calls, we no longer flush the entire
  cache, ever, stale routines are flushed before next use, one at a time.
sql/sql_prepare.cc:
  Move routine metadata validation to open_and_process_routine().
  Fix Bug#49972 (don't swap flags at reprepare).
  Reset Sroutine_hash_entries in reinit_stmt_before_use().
  Remove SP cache invalidation, it's now done by open_tables().
sql/sql_show.cc:
  Fix a warning: remove an unused label.
sql/sql_table.cc:
  Reset mdl_request.ticket for tickets acquired for routines inlined
  through a view, in CHECK TABLE statement, to satisfy an MDL assert.
sql/sql_update.cc:
  Move the cleanup of "translation items" to close_tables_for_reopen(),
  since it's needed in all cases when we back off, not just
  the back-off in multi-update. This fixes a bug when the server
  would crash on attempt to back off when opening tables
  for a statement that uses information_schema tables.

"HANDLER statements within a transaction might lead to deadlocks".
Introduce a notion of a sentinel to MDL_context. A sentinel
is a ticket that separates all tickets in the context into two
groups: before and after it. Currently we can have (and need) only
one designated sentinel -- it separates all locks taken by LOCK
TABLE or HANDLER statement, which must survive COMMIT and ROLLBACK
and all other locks, which must be released at COMMIT or ROLLBACK.
The tricky part is maintaining the sentinel up to date when
someone release its corresponding ticket. This can happen, e.g.
if someone issues DROP TABLE under LOCK TABLES (generally,
see all calls to release_all_locks_for_name()).
MDL_context::release_ticket() is modified to take care of it.

******
A fix and a test case for Bug#46224 "HANDLER statements within a
transaction might lead to deadlocks".

An attempt to mix HANDLER SQL statements, which are transaction-
agnostic, an open multi-statement transaction,
and DDL against the involved tables (in a concurrent connection) 
could lead to a deadlock. The deadlock would occur when
HANDLER OPEN or HANDLER READ would have to wait on a conflicting
metadata lock. If the connection that issued HANDLER statement
also had other metadata locks (say, acquired in scope of a 
transaction), a classical deadlock situation of mutual wait
could occur.

Incompatible change: entering LOCK TABLES mode automatically
closes all open HANDLERs in the current connection.

Incompatible change: previously an attempt to wait on a lock
in a connection that has an open HANDLER statement could wait
indefinitely/deadlock. After this patch, an error ER_LOCK_DEADLOCK
is produced.

The idea of the fix is to merge thd->handler_mdl_context
with the main mdl_context of the connection, used for transactional
locks. This makes deadlock detection possible, since all waits
with locks are "visible" and available to analysis in a single
MDL context of the connection.

Since HANDLER locks and transactional locks have a different life
cycle -- HANDLERs are explicitly open and closed, and so
are HANDLER locks, explicitly acquired and released, whereas
transactional locks "accumulate" till the end of a transaction
and are released only with COMMIT, ROLLBACK and ROLLBACK TO SAVEPOINT,
a concept of "sentinel" was introduced to MDL_context.
All locks, HANDLER and others, reside in the same linked list.
However, a selected element of the list separates locks with
different life cycle. HANDLER locks always reside at the
end of the list, after the sentinel. Transactional locks are
prepended to the beginning of the list, before the sentinel.
Thus, ROLLBACK, COMMIT or ROLLBACK TO SAVEPOINT, only
release those locks that reside before the sentinel. HANDLER locks
must be released explicitly as part of HANDLER CLOSE statement,
or an implicit close. 
The same approach with sentinel
is also employed for LOCK TABLES locks. Since HANDLER and LOCK TABLES
statement has never worked together, the implementation is
made simple and only maintains one sentinel, which is used either
for HANDLER locks, or for LOCK TABLES locks.


mysql-test/include/handler.inc:
  Add test coverage for Bug#46224 "HANDLER statements within a
  transaction might lead to deadlocks".
  Extended HANDLER coverage to cover a mix of HANDLER, transactions
  and DDL statements.
mysql-test/r/handler_innodb.result:
  Update results (Bug#46224).
mysql-test/r/handler_myisam.result:
  Update results (Bug#46224).
sql/lock.cc:
  Remove thd->some_tables_deleted, it's never used.
sql/log_event.cc:
  No need to check for thd->locked_tables_mode, 
  it's done inside release_transactional_locks().
sql/mdl.cc:
  Implement the concept of HANDLER and LOCK TABLES "sentinel".
  Implement a method to clone an acquired ticket.
  Do not return tickets beyond the sentinel when acquiring
  locks, create a copy.
  Remove methods to merge and backup MDL_context, they are now
  not used (Hurra!). This opens a path to a proper constructor
  and destructor of class MDL_context (to be done in a separate
  patch).
  Modify find_ticket() to provide information about where
  the ticket position is with regard to the sentinel.
sql/mdl.h:
  Add declarations necessary for the implementation of the concept
  of "sentinel", a dedicated ticket separating transactional and
  non-transactional locks.
sql/mysql_priv.h:
  Add mark_tmp_table_for_reuse() declaration, 
  a function to "close" a single session (temporary) table.
sql/sql_base.cc:
  Remove thd->some_tables_deleted.
  Modify deadlock-prevention asserts and deadlock detection
  heuristics to take into account that from now on HANDLER locks
  reside in the same locking context.
  Add broadcast_refresh() to mysql_notify_thread_having_shared_lock():
  this is necessary for the case when a thread having a shared lock
  is asleep in tdc_wait_for_old_versions(). This situation is only
  possible with HANDLER t1 OPEN; FLUSH TABLE (since all over code paths
  that lead to tdc_wait_for_old_versions() always have an
  empty MDL_context). Previously the server would simply deadlock
  in this situation.
sql/sql_class.cc:
  Remove now unused member "THD::some_tables_deleted". 
  Move mysql_ha_cleanup() a few lines above in THD::cleanup() 
  to make sure that all handlers are closed when it's time to 
  destroy the MDL_context of this connection.
  Remove handler_mdl_context and handler_tables.
sql/sql_class.h:
  Remove THD::handler_tables, THD::handler_mdl_context,
  THD::some_tables_deleted.
sql/sql_handler.cc:
  Remove thd->handler_tables.
  Remove thd->handler_mdl_context.
  Rewrite mysql_ha_open() to have no special provision for MERGE
  tables, now that we don't have to manipulate with thd->handler_tables
  it's easy to do.
  Remove dead code.
  Fix a bug in mysql_ha_flush() when we would always flush
  a temporary HANDLER when mysql_ha_flush() is called (actually
  mysql_ha_flush() never needs to flush temporary tables).
sql/sql_insert.cc:
  Update a comment, no more thd->some_tables_deleted.
sql/sql_parse.cc:
  Implement an incompatible change: entering LOCK TABLES closes
  active HANDLERs, if any.
  Now that we have a sentinel, we don't need to check
  for thd->locked_tables_mode when releasing metadata locks in
  COMMIT/ROLLBACK.
sql/sql_plist.h:
  Add new (now necessary) methods to the list class.
sql/sql_prepare.cc:
  Make sure we don't release HANDLER locks when rollback to a
  savepoint, set to not keep locks taken at PREPARE.
sql/sql_servers.cc:
  Update to a new signature of MDL_context::release_all_locks().
sql/sql_table.cc:
  Remove thd->some_tables_deleted.
sql/transaction.cc:
  Add comments. 
  Make sure rollback to (MDL) savepoint works under LOCK TABLES and
  with HANDLER tables.

Bug#16565 mysqld --help --verbose does not order variablesBug#20413 sql_slave_skip_counter is not shown in show variables
Bug#20415 Output of mysqld --help --verbose is incomplete
Bug#25430 variable not found in SELECT @@global.ft_max_word_len;
Bug#32902 plugin variables don't know their names
Bug#34599 MySQLD Option and Variable Reference need to be consistent in formatting!
Bug#34829 No default value for variable and setting default does not raise error
Bug#34834 ? Is accepted as a valid sql mode
Bug#34878 Few variables have default value according to documentation but error occurs  
Bug#34883 ft_boolean_syntax cant be assigned from user variable to global var.
Bug#37187 `INFORMATION_SCHEMA`.`GLOBAL_VARIABLES`: inconsistent status
Bug#40988 log_output_basic.test succeeded though syntactically false.
Bug#41010 enum-style command-line options are not honoured (maria.maria-recover fails)
Bug#42103 Setting key_buffer_size to a negative value may lead to very large allocations 
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
Bug#44797 plugins w/o command-line options have no disabling option in --help
Bug#46314 string system variables don't support expressions
Bug#46470 sys_vars.max_binlog_cache_size_basic_32 is broken
Bug#46586 When using the plugin interface the type "set" for options caused a crash.
Bug#47212 Crash in DBUG_PRINT in mysqltest.cc when trying to print octal number
Bug#48758 mysqltest crashes on sys_vars.collation_server_basic in gcov builds
Bug#49417 some complaints about mysqld --help --verbose output
Bug#49540 DEFAULT value of binlog_format isn't the default value
Bug#49640 ambiguous option '--skip-skip-myisam' (double skip prefix)
Bug#49644 init_connect and \0
Bug#49645 init_slave and multi-byte characters
Bug#49646 mysql --show-warnings crashes when server dies


CMakeLists.txt:
  Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
client/mysql.cc:
  don't crash with --show-warnings when mysqld dies
config/ac-macros/plugins.m4:
  Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
include/my_getopt.h:
  comments
include/my_pthread.h:
  fix double #define
mysql-test/mysql-test-run.pl:
  run sys_vars suite by default
  properly recognize envirinment variables (e.g. MTR_MAX_SAVE_CORE) set to 0
  escape gdb command line arguments
mysql-test/suite/sys_vars/r/rpl_init_slave_func.result:
  init_slave+utf8 bug
mysql-test/suite/sys_vars/t/rpl_init_slave_func.test:
  init_slave+utf8 bug
mysys/my_getopt.c:
  Bug#34599 MySQLD Option and Variable Reference need to be consistent in formatting!
  Bug#46586 When using the plugin interface the type "set" for options caused a crash.
  Bug#49640 ambiguous option '--skip-skip-myisam' (double skip prefix)
mysys/typelib.c:
  support for flagset
sql/ha_ndbcluster.cc:
  backport from telco tree
sql/item_func.cc:
  Bug#49644 init_connect and \0
  Bug#49645 init_slave and multi-byte characters
sql/sql_builtin.cc.in:
  Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
sql/sql_plugin.cc:
  Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
  Bug#32902 plugin variables don't know their names
  Bug#44797 plugins w/o command-line options have no disabling option in --help
sql/sys_vars.cc:
  all server variables are defined here
storage/myisam/ft_parser.c:
  remove unnecessary updates of param->quot
storage/myisam/ha_myisam.cc:
  myisam_* variables belong here
strings/my_vsnprintf.c:
  %o and %llx
unittest/mysys/my_vsnprintf-t.c:
  %o and %llx tests
vio/viosocket.c:
  bugfix: fix @@wait_timeout to work with socket timeouts (vs. alarm thread)

Bug#42546 Backup: RESTORE fails, thinking it finds an existing table

The problem occured when a MDL locking conflict happened for a non-existent 
table between a CREATE and a INSERT statement. The code for CREATE 
interpreted this lock conflict to mean that the table existed, 
which meant that the statement failed when it should not have.
The problem could occur for CREATE TABLE, CREATE TABLE LIKE and
ALTER TABLE RENAME.

This patch fixes the problem for CREATE TABLE and CREATE TABLE LIKE.
It is based on code backported from the mysql-6.1-fk tree written
by Dmitry Lenev. CREATE now uses normal open_and_lock_tables() code 
to acquire exclusive locks. This means that for the test case in the bug 
description, CREATE will wait until INSERT completes so that it can 
get the exclusive lock. This resolves the reported bug.

The patch also prohibits CREATE TABLE and CREATE TABLE LIKE under 
LOCK TABLES. Note that this is an incompatible change and must 
be reflected in the documentation. Affected test cases have been
updated.

mdl_sync.test contains tests for CREATE TABLE and CREATE TABLE LIKE.

Fixing the issue for ALTER TABLE RENAME is beyond the scope of this
patch. ALTER TABLE cannot be prohibited from working under LOCK TABLES
as this could seriously impact customers and a proper fix would require
a significant rewrite.

2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1
- initial changeset that introduced the fix for 
Bug#989 and follow up fixes for all test suite failures
introduced in the initial changeset. 
------------------------------------------------------------
revno: 2617.31.1
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 4284-6.0
timestamp: Fri 2009-03-06 19:17:00 -0300
message:
Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order
WL#4284: Transactional DDL locking

Currently the MySQL server does not keep metadata locks on
schema objects for the duration of a transaction, thus failing
to guarantee the integrity of the schema objects being used
during the transaction and to protect then from concurrent
DDL operations. This also poses a problem for replication as
a DDL operation might be replicated even thought there are
active transactions using the object being modified.

The solution is to defer the release of metadata locks until
a active transaction is either committed or rolled back. This
prevents other statements from modifying the table for the
entire duration of the transaction. This provides commitment
ordering for guaranteeing serializability across multiple
transactions.

- Incompatible change:

If MySQL's metadata locking system encounters a lock conflict,
the usual schema is to use the try and back-off technique to
avoid deadlocks -- this schema consists in releasing all locks
and trying to acquire them all in one go.

But in a transactional context this algorithm can't be utilized
as its not possible to release locks acquired during the course
of the transaction without breaking the transaction commitments.
To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be
returned if a lock conflict is encountered during a transaction.

Let's consider an example:

A transaction has two statements that modify table t1, then table
t2, and then commits. The first statement of the transaction will
acquire a shared metadata lock on table t1, and it will be kept
utill COMMIT to ensure serializability.

At the moment when the second statement attempts to acquire a
shared metadata lock on t2, a concurrent ALTER or DROP statement
might have locked t2 exclusively. The prescription of the current
locking protocol is that the acquirer of the shared lock backs off
-- gives up all his current locks and retries. This implies that
the entire multi-statement transaction has to be rolled back.

- Incompatible change:

FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ
LOCK won't cause locked tables to be implicitly unlocked anymore.


mysql-test/extra/binlog_tests/drop_table.test:
  Add test case for Bug#989.
mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test:
  Fix test case to reflect the fact that transactions now hold
  metadata locks for the duration of a transaction.
mysql-test/include/mix1.inc:
  Fix test case to reflect the fact that transactions now hold
  metadata locks for the duration of a transaction.
mysql-test/include/mix2.inc:
  Fix test case to reflect the fact that transactions now hold
  metadata locks for the duration of a transaction.
mysql-test/r/flush_block_commit.result:
  Update test case result (WL#4284).
mysql-test/r/flush_block_commit_notembedded.result:
  Update test case result (WL#4284).
mysql-test/r/innodb.result:
  Update test case result (WL#4284).
mysql-test/r/innodb_mysql.result:
  Update test case result (WL#4284).
mysql-test/r/lock.result:
  Add test case result for an effect of WL#4284/Bug#989
  (all locks should be released when a connection terminates).
mysql-test/r/mix2_myisam.result:
  Update test case result (effects of WL#4284/Bug#989).
mysql-test/r/not_embedded_server.result:
  Update test case result (effects of WL#4284/Bug#989).
  Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES.
mysql-test/r/partition_innodb_semi_consistent.result:
  Update test case result (effects of WL#4284/Bug#989).
mysql-test/r/partition_sync.result:
  Temporarily disable the test case for Bug#43867,
  which will be fixed by a subsequent backport.
mysql-test/r/ps.result:
  Add a test case for effect of PREPARE on transactional
  locks: we take a savepoint at beginning of PREAPRE
  and release it at the end. Thus PREPARE does not 
  accumulate metadata locks (Bug#989/WL#4284).
mysql-test/r/read_only_innodb.result:
  Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_row_drop_tbl.result:
  Add a test case result (WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result:
  Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result:
  Add a test case result (WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result:
  Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_unsafe.result:
  A side effect of Bug#989 -- slightly different table map ids.
mysql-test/suite/binlog/t/binlog_row_drop_tbl.test:
  Add a test case for WL#4284/Bug#989.
mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test:
  Add a test case for WL#4284/Bug#989.
mysql-test/suite/binlog/t/binlog_stm_row.test:
  Update to the new state name. This
  is actually a follow up to another patch for WL#4284, 
  that changes Locked thread state to Table lock.
mysql-test/suite/ndb/r/ndb_index_ordered.result:
  Remove result for disabled part of the test case.
mysql-test/suite/ndb/t/disabled.def:
  Temporarily disable a test case (Bug#45621).
mysql-test/suite/ndb/t/ndb_index_ordered.test:
  Disable a part of a test case (needs update to
  reflect semantics of Bug#989).
mysql-test/suite/rpl/t/disabled.def:
  Disable tests made meaningless by transactional metadata
  locking.
mysql-test/suite/sys_vars/r/autocommit_func.result:
  Add a commit (Bug#989).
mysql-test/suite/sys_vars/t/autocommit_func.test:
  Add a commit (Bug#989).
mysql-test/t/flush_block_commit.test:
  Fix test case to reflect the fact that transactions now hold
  metadata locks for the duration of a transaction.
mysql-test/t/flush_block_commit_notembedded.test:
  Fix test case to reflect the fact that transactions now hold
  metadata locks for the duration of a transaction.
  Add a test case for transaction-scope locks and the global
  read lock (Bug#989/WL#4284).
mysql-test/t/innodb.test:
  Fix test case to reflect the fact that transactions now hold
  metadata locks for the duration of a transaction
  (effects of Bug#989/WL#4284).
mysql-test/t/lock.test:
  Add a test case for Bug#989/WL#4284.
mysql-test/t/not_embedded_server.test:
  Add a test case for Bug#989/WL#4284.
mysql-test/t/partition_innodb_semi_consistent.test:
  Replace TRUNCATE with DELETE, to not issue
  an implicit commit of a transaction, and not depend
  on metadata locks.
mysql-test/t/partition_sync.test:
  Temporarily disable the test case for Bug#43867,
  which needs a fix to be backported from 6.0.
mysql-test/t/ps.test:
  Add a test case for semantics of PREPARE and transaction-scope
  locks: metadata locks on tables used in PREPARE are enclosed into a
  temporary savepoint, taken at the beginning of PREPARE,
  and released at the end. Thus PREPARE does not effect
  what locks a transaction owns.
mysql-test/t/read_only_innodb.test:
  Fix test case to reflect the fact that transactions now hold
  metadata locks for the duration of a transaction 
  (Bug#989/WL#4284).
  
  Wait for the read_only statement to actually flush tables before
  sending other concurrent statements that depend on its state.
mysql-test/t/xa.test:
  Fix test case to reflect the fact that transactions now hold
  metadata locks for the duration of a transaction 
  (Bug#989/WL#4284).
sql/ha_ndbcluster_binlog.cc:
  Backport bits of changes of ha_ndbcluster_binlog.cc
  from 6.0, to fix the failing binlog test suite with
  WL#4284. WL#4284 implementation does not work
  with 5.1 implementation of ndbcluster binlog index.
sql/log_event.cc:
  Release metadata locks after issuing a commit.
sql/mdl.cc:
  Style changes (WL#4284).
sql/mysql_priv.h:
  Rename parameter to match the name used in the definition (WL#4284).
sql/rpl_injector.cc:
  Release metadata locks on commit (WL#4284).
sql/rpl_rli.cc:
  Remove assert made meaningless, metadata locks are released
  at the end of the transaction.
sql/set_var.cc:
  Close tables and release locks if autocommit mode is set.
sql/slave.cc:
  Release metadata locks after a rollback.
sql/sql_acl.cc:
  Don't implicitly unlock locked tables. Issue a implicit commit
  at the end and unlock tables.
sql/sql_base.cc:
  Defer the release of metadata locks when closing tables
  if not required to.
  Issue a deadlock error if the locking protocol requires
  that a transaction re-acquire its locks.
  
  Release metadata locks when closing tables for reopen.
sql/sql_class.cc:
  Release metadata locks if the thread is killed.
sql/sql_parse.cc:
  Release metadata locks after implicitly committing a active
  transaction, or after explicit commits or rollbacks.
sql/sql_plugin.cc:
  
  Allocate MDL request on the stack as the use of the table
  is contained within the function. It will be removed from
  the context once close_thread_tables is called at the end
  of the function.
sql/sql_prepare.cc:
  The problem is that the prepare phase of the CREATE TABLE
  statement takes a exclusive metadata lock lock and this can
  cause a self-deadlock the thread already holds a shared lock
  on the table being that should be created.
  
  The solution is to make the prepare phase take a shared
  metadata lock when preparing a CREATE TABLE statement. The
  execution of the statement will still acquire a exclusive
  lock, but won't cause any problem as it issues a implicit
  commit.
  
  After some discussions with stakeholders it has been decided that
  metadata locks acquired during a PREPARE statement must be released
  once the statement is prepared even if it is prepared within a multi
  statement transaction.
sql/sql_servers.cc:
  Don't implicitly unlock locked tables. Issue a implicit commit
  at the end and unlock tables.
sql/sql_table.cc:
  Close table and release metadata locks after a admin operation.
sql/table.h:
  The problem is that the prepare phase of the CREATE TABLE
  statement takes a exclusive metadata lock lock and this can
  cause a self-deadlock the thread already holds a shared lock
  on the table being that should be created.
  
  The solution is to make the prepare phase take a shared
  metadata lock when preparing a CREATE TABLE statement. The
  execution of the statement will still acquire a exclusive
  lock, but won't cause any problem as it issues a implicit
  commit.
sql/transaction.cc:
  Release metadata locks after the implicitly committed due
  to a new transaction being started. Also, release metadata
  locks acquired after a savepoint if the transaction is rolled
  back to the save point.
  
  The problem is that in some cases transaction-long metadata locks
  could be released before the transaction was committed. This could
  happen when a active transaction was ended by a "START TRANSACTION"
  or "BEGIN" statement, in which case the metadata locks would be
  released before the actual commit of the active transaction.
  
  The solution is to defer the release of metadata locks to after the
  transaction has been implicitly committed. No test case is provided
  as the effort to provide one is too disproportional to the size of
  the fix.

------------------------------------------------------------
revno: 2630.4.16
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Thu 2008-05-29 09:45:02 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  After review changes in progress.

  Tweaked some comments and did some renames to
  avoid ambiguites.


sql/mysql_priv.h:
  Removed name_lock_locked_table() function.
sql/sql_base.cc:
  Got rid of name_lock_locked_table() function after replacing
  the only call to it with its body.
  Simplified open_table() code by making "action" argument
  mandatory (i.e. one now should always pass non-0 pointer
  in this argument).
  Renamed TABLE_LIST::open_table_type to open_type to
  avoid confusing it with type of table.
  Adjusted comments according to review.
sql/sql_handler.cc:
  Added comment clarifying in which cases we can have TABLE::mdl_lock
  set to 0.
sql/sql_insert.cc:
  Now the 4th argument of open_table() is mandatory (it makes
  no sense to complicate open_table() code when we can simply
  pass dummy variable).
sql/sql_parse.cc:
  Renamed TABLE_LIST::open_table_type to open_type to
  avoid confusing it with type of table.
sql/sql_prepare.cc:
  Renamed TABLE_LIST::open_table_type to open_type to
  avoid confusing it with type of table.
sql/sql_table.cc:
  Now the 4th argument of open_table() is mandatory (it makes
  no sense to complicate open_table() code when we can simply
  pass dummy variable).
sql/sql_trigger.cc:
  Replaced the only call to name_lock_locked_table() function
  with its body.
sql/sql_view.cc:
  Renamed TABLE_LIST::open_table_type to open_type to
  avoid confusing it with type of table.
sql/table.h:
  Renamed TABLE_LIST::open_table_type to open_type (to
  avoid confusing it with type of table) and improved
  comments describing this member.

Backport of:
------------------------------------------------------------
revno: 2630.4.1
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Fri 2008-05-23 17:54:03 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  After review fixes in progress.
------------------------------------------------------------

This is the first patch in series. It transforms the metadata 
locking subsystem to use a dedicated module (mdl.h,cc). No 
significant changes in the locking protocol. 
The import passes the test suite with the exception of 
deprecated/removed 6.0 features, and MERGE tables. The latter
are subject to a fix by WL#4144.
Unfortunately, the original changeset comments got lost in a merge,
thus this import has its own (largely insufficient) comments.

This patch fixes Bug#25144 "replication / binlog with view breaks".
Warning: this patch introduces an incompatible change:
Under LOCK TABLES, it's no longer possible to FLUSH a table that 
was not locked for WRITE.
Under LOCK TABLES, it's no longer possible to DROP a table or
VIEW that was not locked for WRITE.

******
Backport of:
------------------------------------------------------------
revno: 2630.4.2
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Sat 2008-05-24 14:03:45 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  After review fixes in progress.

******
Backport of:
------------------------------------------------------------
revno: 2630.4.3
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Sat 2008-05-24 14:08:51 +0400
message:
  WL#3726 "DDL locking for all metadata objects"

  Fixed failing Windows builds by adding mdl.cc to the lists
  of files needed to build server/libmysqld on Windows.

******
Backport of:
------------------------------------------------------------
revno: 2630.4.4
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Sat 2008-05-24 21:57:58 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  Fix for assert failures in kill.test which occured when one
  tried to kill ALTER TABLE statement on merge table while it
  was waiting in wait_while_table_is_used() for other connections
  to close this table.

  These assert failures stemmed from the fact that cleanup code
  in this case assumed that temporary table representing new
  version of table was open with adding to THD::temporary_tables
  list while code which were opening this temporary table wasn't
  always fulfilling this.

  This patch changes code that opens new version of table to
  always do this linking in. It also streamlines cleanup process
  for cases when error occurs while we have new version of table
  open.

******
WL#3726 "DDL locking for all metadata objects"
Add libmysqld/mdl.cc to .bzrignore.
******
Backport of:
------------------------------------------------------------
revno: 2630.4.6
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Sun 2008-05-25 00:33:22 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  Addition to the fix of assert failures in kill.test caused by
  changes for this worklog.


Make sure we close the new table only once.

.bzrignore:
  Add libmysqld/mdl.cc
libmysqld/CMakeLists.txt:
  Added mdl.cc to the list of files needed for building of libmysqld.
libmysqld/Makefile.am:
  Added files implementing new meta-data locking subsystem to the server.
mysql-test/include/handler.inc:
  Use separate connection for waiting while threads performing DDL
  operations conflicting with open HANDLER tables reach blocked
  state. This is required because now we check and close tables open
  by HANDLER statements in this connection conflicting with DDL in
  another each time open_tables() is called and thus select from I_S
  which is used for waiting will unblock DDL operations if issued
  from connection with open HANDLERs.
mysql-test/r/create.result:
  Adjusted test case after change in implementation of CREATE TABLE
  ... SELECT.  We no longer have special check in open_table() which
  catches the case when we select from the table created. Instead we
  rely on unique_table() call which happens after opening and
  locking all tables.
mysql-test/r/flush.result:
  FLUSH TABLES WITH READ LOCK can no longer happen under LOCK
  TABLES.  Updated test accordingly.
mysql-test/r/flush_table.result:
  Under LOCK TABLES we no longer allow to do FLUSH TABLES for tables
  locked for read. Updated test accordingly.
mysql-test/r/handler_innodb.result:
  Use separate connection for waiting while threads performing DDL
  operations conflicting with open HANDLER tables reach blocked
  state. This is required because now we check and close tables open
  by HANDLER statements in this connection conflicting with DDL in
  another each time open_tables() is called and thus select from I_S
  which is used for waiting will unblock DDL operations if issued
  from connection with open HANDLERs.
mysql-test/r/handler_myisam.result:
  Use separate connection for waiting while threads performing DDL
  operations conflicting with open HANDLER tables reach blocked
  state. This is required because now we check and close tables open
  by HANDLER statements in this connection conflicting with DDL in
  another each time open_tables() is called and thus select from I_S
  which is used for waiting will unblock DDL operations if issued
  from connection with open HANDLERs.
mysql-test/r/information_schema.result:
  Additional test for WL#3726 "DDL locking for all metadata
  objects".  Check that we use high-priority metadata lock requests
  when filling I_S tables.
  
  Rearrange tests to match 6.0 better (fewer merge conflicts).
mysql-test/r/kill.result:
  Added tests checking that DDL and DML statements waiting for
  metadata locks can be interrupted by KILL command.
mysql-test/r/lock.result:
  One no longer is allowed to do DROP VIEW under LOCK TABLES even if
  this view is locked by LOCK TABLES. The problem is that in such
  situation write locks on view are not mutually exclusive so
  upgrading metadata lock which is required for dropping of view
  will lead to deadlock.
mysql-test/r/partition_column_prune.result:
  Update results (same results in 6.0), WL#3726
mysql-test/r/partition_pruning.result:
  Update results (same results in 6.0), WL#3726
mysql-test/r/ps_ddl.result:
  We no longer invalidate prepared CREATE TABLE ... SELECT statement
  if target table changes. This is OK since it is not strictly
  necessary.
  
  
  The first change is wrong, is caused by FLUSH TABLE
  now flushing all unused tables. This is a regression that
  Dmitri fixed in 6.0 in a follow up patch.
mysql-test/r/sp.result:
  Under LOCK TABLES we no longer allow accessing views which were
  not explicitly locked. To access view we need to obtain metadata
  lock on it and doing this under LOCK TABLES may lead to deadlocks.
mysql-test/r/view.result:
  One no longer is allowed to do DROP VIEW under LOCK TABLES even if
  this view is locked by LOCK TABLES. The problem is that in such
  situation even "write locks" on view are not mutually exclusive so
  upgrading metadata lock which is required for dropping of view
  will lead to deadlock
mysql-test/r/view_grant.result:
  ALTER VIEW implementation was changed to open a view only after
  checking that user which does alter has appropriate privileges on
  it. This means that in case when user's privileges are
  insufficient for this we won't check that new view definer is the
  same as original one or user performing alter has SUPER privilege.
  Adjusted test case accordingly.
mysql-test/r/view_multi.result:
  Added test case for bug#25144 "replication / binlog with view
  breaks".
mysql-test/suite/rpl/t/disabled.def:
  Disable test for deprecated features (they don't work with new MDL).
mysql-test/t/create.test:
  Adjusted test case after change in implementation of CREATE TABLE
  ... SELECT.  We no longer have special check in open_table() which
  catches the case when we select from the table created. Instead we
  rely on unique_table() call which happens after opening and
  locking all tables.
mysql-test/t/disabled.def:
  Disable merge.test, subject of WL#4144
mysql-test/t/flush.test:
  
  FLUSH TABLES WITH READ LOCK can no longer happen under LOCK
  TABLES.  Updated test accordingly.
mysql-test/t/flush_table.test:
  Under LOCK TABLES we no longer allow to do FLUSH TABLES for tables
  locked for read. Updated test accordingly.
mysql-test/t/information_schema.test:
  Additional test for WL#3726 "DDL locking for all metadata
  objects".  Check that we use high-priority metadata lock requests
  when filling I_S tables.
  
  Rearrange the results for easier merges with 6.0.
mysql-test/t/kill.test:
  Added tests checking that DDL and DML statements waiting for
  metadata locks can be interrupted by KILL command.
mysql-test/t/lock.test:
  One no longer is allowed to do DROP VIEW under LOCK TABLES even if
  this view is locked by LOCK TABLES. The problem is that in such
  situation write locks on view are not mutually exclusive so
  upgrading metadata lock which is required for dropping of view
  will lead to deadlock.
mysql-test/t/lock_multi.test:
  Adjusted test case to the changes of status in various places
  caused by change in implementation FLUSH TABLES WITH READ LOCK,
  which is now takes global metadata lock before flushing tables and
  therefore waits on at these places.
mysql-test/t/ps_ddl.test:
  We no longer invalidate prepared CREATE TABLE ... SELECT statement
  if target table changes. This is OK since it is not strictly
  necessary.
  
  
  The first change is wrong, is caused by FLUSH TABLE
  now flushing all unused tables. This is a regression that
  Dmitri fixed in 6.0 in a follow up patch.
mysql-test/t/sp.test:
  Under LOCK TABLES we no longer allow accessing views which were
  not explicitly locked. To access view we need to obtain metadata
  lock on it and doing this under LOCK TABLES may lead to deadlocks.
mysql-test/t/trigger_notembedded.test:
  Adjusted test case to the changes of status in various places
  caused by change in implementation FLUSH TABLES WITH READ LOCK,
  which is now takes global metadata lock before flushing tables and
  therefore waits on at these places.
mysql-test/t/view.test:
  One no longer is allowed to do DROP VIEW under LOCK TABLES even if
  this view is locked by LOCK TABLES. The problem is that in such
  situation even "write locks" on view are not mutually exclusive so
  upgrading metadata lock which is required for dropping of view
  will lead to deadlock.
mysql-test/t/view_grant.test:
  ALTER VIEW implementation was changed to open a view only after
  checking that user which does alter has appropriate privileges on
  it. This means that in case when user's privileges are
  insufficient for this we won't check that new view definer is the
  same as original one or user performing alter has SUPER privilege.
  Adjusted test case accordingly.
mysql-test/t/view_multi.test:
  Added test case for bug#25144 "replication / binlog with view
  breaks".
sql/CMakeLists.txt:
  Added mdl.cc to the list of files needed for building of server.
sql/Makefile.am:
  Added files implementing new meta-data locking subsystem to the
  server.
sql/event_db_repository.cc:
  
  Allocate metadata lock requests objects (MDL_LOCK) on execution
  memory root in cases when TABLE_LIST objects is also allocated
  there or on stack.
sql/ha_ndbcluster.cc:
  Adjusted code to work nicely with new metadata locking subsystem.
  close_cached_tables() no longer has wait_for_placeholder argument.
  Instead of relying on this parameter and related behavior FLUSH
  TABLES WITH READ LOCK now takes global shared metadata lock.
sql/ha_ndbcluster_binlog.cc:
  Adjusted code to work with new metadata locking subsystem.
  close_cached_tables() no longer has wait_for_placeholder argument.
  Instead of relying on this parameter and related behavior FLUSH
  TABLES WITH READ LOCK now takes global shared metadata lock.
sql/handler.cc:
  update_frm_version():
    Directly update TABLE_SHARE::mysql_version member instead of
    going through all TABLE instances for this table (old code was a
    legacy from pre-table-definition-cache days).
sql/lock.cc:
  Use new metadata locking subsystem. Threw away most of functions
  related to name locking as now one is supposed to use metadata
  locking API instead.  In lock_global_read_lock() and
  unlock_global_read_lock() in order to avoid problems with global
  read lock sneaking in at the moment when we perform FLUSH TABLES
  or ALTER TABLE under LOCK TABLES and when tables being reopened
  are protected only by metadata locks we also have to take global
  shared meta data lock.
sql/log_event.cc:
  Adjusted code to work with new metadata locking subsystem.  For
  tables open by slave thread for applying RBR events allocate
  memory for lock request object in the same chunk of memory as
  TABLE_LIST objects for them. In order to ensure that we keep these
  objects around until tables are open always close tables before
  calling Relay_log_info::clear_tables_to_lock(). Use new auxiliary
  Relay_log_info::slave_close_thread_tables() method to enforce
  this.
sql/log_event_old.cc:
  Adjusted code to work with new metadata locking subsystem.  Since
  for tables open by slave thread for applying RBR events memory for
  lock request object is allocated in the same chunk of memory as
  TABLE_LIST objects for them we have to ensure that we keep these
  objects around until tables are open. To ensure this we always
  close tables before calling
  Relay_log_info::clear_tables_to_lock(). To enfore this we use
  new auxiliary Relay_log_info::slave_close_thread_tables()
  method.
sql/mdl.cc:
  Implemented new metadata locking subsystem and API described in
  WL3726 "DDL locking for all metadata objects".
sql/mdl.h:
  Implemented new metadata locking subsystem and API described in
  WL3726 "DDL locking for all metadata objects".
sql/mysql_priv.h:
  - close_thread_tables()/close_tables_for_reopen() now has one more
    argument which indicates that metadata locks should be released
    but not removed from the context in order to be used later in
    mdl_wait_for_locks() and tdc_wait_for_old_version().
  - close_cached_table() routine is no longer public.
  - Thread waiting in wait_while_table_is_used() can be now killed
    so this function returns boolean to make caller aware of such
    situation.
  - We no longer have  table cache as separate entity instead used
    and unused TABLE instances are linked to TABLE_SHARE objects in
    table definition cache.
  - Now third argument of open_table() is also used for requesting
    table repair or auto-discovery of table's new definition. So its
    type was changed from bool to enum.
  - Added tdc_open_view() function for opening view by getting its
    definition from disk (and table cache in future).
  - reopen_name_locked_table() no longer needs "link_in" argument as
    now we have exclusive metadata locks instead of dummy TABLE
    instances when this function is called.
  - find_locked_table() now takes head of list of TABLE instances
    instead of always scanning through THD::open_tables list. Also
    added find_write_locked_table() auxiliary.
  - reopen_tables(), close_cached_tables() no longer have
    mark_share_as_old and wait_for_placeholder arguments. Instead of
    relying on this parameters and related behavior FLUSH TABLES
    WITH READ LOCK now takes global shared metadata lock.
  - We no longer need drop_locked_tables() and
    abort_locked_tables().
  - mysql_ha_rm_tables() now always assume that LOCK_open is not
    acquired by caller.
  - Added notify_thread_having_shared_lock() callback invoked by
    metadata locking subsystem when acquiring an exclusive lock, for
    each thread that has a conflicting shared metadata lock.
  - Introduced expel_table_from_cache() as replacement for
    remove_table_from_cache() (the main difference is that this new
    function assumes that caller follows metadata locking protocol
    and never waits).
  - Threw away most of functions related to name locking. One should
    use new metadata locking subsystem and API instead.
sql/mysqld.cc:
  Got rid of call initializing/deinitializing table cache since now
  it is embedded into table definition cache. Added calls for
  initializing/ deinitializing metadata locking subsystem.
sql/rpl_rli.cc:
  Introduced auxiliary Relay_log_info::slave_close_thread_tables()
  method which is used for enforcing that we always close tables
  open for RBR before deallocating TABLE_LIST elements and MDL_LOCK
  objects for them.
sql/rpl_rli.h:
  Introduced auxiliary Relay_log_info::slave_close_thread_tables()
  method which is used for enforcing that we always close tables
  open for RBR before deallocating TABLE_LIST elements and MDL_LOCK
  objects for them.
sql/set_var.cc:
  close_cached_tables() no longer has wait_for_placeholder argument.
  Instead of relying on this parameter and related behavior FLUSH
  TABLES WITH READ LOCK now takes global shared metadata lock.
sql/sp_head.cc:
  For tables added to the statement's table list by prelocking
  algorithm we allocate these objects either on the same memory as
  corresponding table list elements or on THD::locked_tables_root
  (if we are building table list for LOCK TABLES).
sql/sql_acl.cc:
  Allocate metadata lock requests objects (MDL_LOCK) on execution
  memory root in cases when we use stack TABLE_LIST objects to open
  tables.  Got rid of redundant code by using unlock_locked_tables()
  function.
sql/sql_base.cc:
  Changed code to use new MDL subsystem. Got rid of separate table
  cache.  Now used and unused TABLE instances are linked to the
  TABLE_SHAREs in table definition cache.
  
  check_unused():
    Adjusted code to the fact that we no longer have separate table
    cache.  Removed dead code.
  table_def_free():
    Free TABLE instances referenced from TABLE_SHARE objects before
    destroying table definition cache.
  get_table_share():
    Added assert which ensures that noone will be able to access
    table (and its share) without acquiring some kind of metadata
    lock first.
  close_handle_and_leave_table_as_lock():
    Adjusted code to the fact that TABLE instances now are linked to
    list in TABLE_SHARE.
  list_open_tables():
    Changed this function to use table definition cache instead of
    table cache.
  free_cache_entry():
    Unlink freed TABLE elements from the list of all TABLE instances
    for the table in TABLE_SHARE.
  kill_delayed_thread_for_table():
    Added auxiliary for killing delayed insert threads for
    particular table.
  close_cached_tables():
    Got rid of wait_for_refresh argument as we now rely on global
    shared metadata lock to prevent FLUSH WITH READ LOCK sneaking in
    when we are reopening tables. Heavily reworked this function to
    use new MDL code and not to rely on separate table cache entity.
  close_open_tables():
    We no longer have separate table cache.
  close_thread_tables():
    Release metadata locks after closing all tables. Added skip_mdl
    argument which allows us not to remove metadata lock requests
    from the context in case when we are going to use this requests
    later in mdl_wait_for_locks() and tdc_wait_for_old_versions().
  close_thread_table()/close_table_for_reopen():
    Since we no longer have separate table cache and all TABLE
    instances are linked to TABLE_SHARE objects in table definition
    cache we have to link/unlink TABLE object to/from appropriate
    lists in the share.
  name_lock_locked_table():
   Moved redundant code to find_write_locked_table() function and
    adjusted code to the fact that wait_while_table_is_used() can
    now return with an error if our thread is killed.
  reopen_table_entry():
    We no longer need "link_in" argument as with MDL we no longer
    call this function with dummy TABLE object pre-allocated and
    added to the THD::open_tables. Also now we add newly-open TABLE
    instance to the list of share's used TABLE instances.
  table_cache_insert_placeholder():
    Got rid of name-locking legacy.
  lock_table_name_if_not_cached():
    Moved to sql_table.cc the only place where it is used. It was
    also reimplemented using new MDL API.
  open_table():
    - Reworked this function to use new MDL subsystem.
    - Changed code to deal with table definition cache directly
      instead of going through separate table cache.
    - Now third argument is also used for requesting table repair
      or auto-discovery of table's new definition. So its type was
      changed from bool to enum.
  find_locked_table()/find_write_locked_table():
    Accept head of list of TABLE objects as first argument and use
    this list instead of always searching in THD::open_tables list.
    Also added auxiliary for finding write-locked locked tables.
  reopen_table():
    Adjusted function to work with new MDL subsystem and to properly
    manuipulate with lists of used/unused TABLE instaces in
    TABLE_SHARE.
  reopen_tables():
    Removed mark_share_as_old parameter. Instead of relying on it
    and related behavior FLUSH TABLES WITH READ LOCK now takes
    global shared metadata lock. Changed code after removing
    separate table cache.
  drop_locked_tables()/abort_locked_tables():
    Got rid of functions which are no longer needed.
    unlock_locked_tables():
    Moved this function from sql_parse.cc and changed it to release
    memory which was used for allocating metadata lock requests for
    tables open and locked by LOCK TABLES.
  tdc_open_view():
    Intoduced function for opening a view by getting its definition
    from disk (and table cache in future).
  reopen_table_entry():
    Introduced function for opening table definitions while holding
    exclusive metatadata lock on it.
  open_unireg_entry():
   Got rid of this function. Most of its functionality is relocated
    to open_table() and open_table_fini() functions, and some of it
    to reopen_table_entry() and tdc_open_view(). Also code
    resposible for auto-repair and auto-discovery of tables was
    moved to separate function.
  open_table_entry_fini():
    Introduced function which contains common actions which finalize
    process of TABLE object creation.
  auto_repair_table():
    Moved code responsible for auto-repair of table being opened
    here.
  handle_failed_open_table_attempt()
    Moved code responsible for handling failing attempt to open
    table to one place (retry due to lock conflict/old version,
    auto-discovery and repair).
  open_tables():
    - Flush open HANDLER tables if they have old version of if there
      is conflicting metadata lock against them (before this moment
      we had this code in open_table()).
    - When we open view which should be processed via derived table
      on the second execution of prepared statement or stored
      routine we still should call open_table() for it in order to
      obtain metadata lock on it and prepare its security context.
    - In cases when we discover that some special handling of
      failure to open table is needed call
      handle_failed_open_table_attempt() which handles all such
      scenarios.
  open_ltable():
    Handling of various special scenarios of failure to open a table
    was moved to separate handle_failed_open_table_attempt()
    function.
  remove_db_from_cache():
    Removed this function as it is no longer used.
  notify_thread_having_shared_lock():
    Added callback which is invoked by MDL subsystem when acquiring
    an exclusive lock, for each thread that has a conflicting shared
    metadata lock.
  expel_table_from_cache():
    Introduced function for removing unused TABLE instances. Unlike
    remove_table_from_cache() it relies on caller following MDL
    protocol and having appropriate locks when calling it and thus
    does not do any waiting if table is still in use.
  tdc_wait_for_old_version():
    Added function which allows open_tables() to wait in cases when
    we discover that we should back-off due to presence of old
    version of table.
  abort_and_upgrade_lock():
    Use new MDL calls.
  mysql_wait_completed_table():
    Got rid of unused function.
  open_system_tables_for_read/for_update()/performance_schema_table():
    Allocate MDL_LOCK objects on execution memory root in cases when
    TABLE_LIST objects for corresponding tables is allocated on
    stack.
  close_performance_schema_table():
    Release metadata locks after closing tables.
  ******
  Use I_P_List for free/used tables list in the table share.
sql/sql_binlog.cc:
  Use Relay_log_info::slave_close_thread_tables() method to enforce
  that we always close tables open for RBR before deallocating
  TABLE_LIST elements and MDL_LOCK objects for them.
sql/sql_class.cc:
  Added meta-data locking contexts as part of Open_tables_state
  context.  Also introduced THD::locked_tables_root memory root
  which is to be used for allocating MDL_LOCK objects for tables in
  LOCK TABLES statement (end of lifetime for such objects is UNLOCK
  TABLES so we can't use statement or execution root for them).
sql/sql_class.h:
  Added meta-data locking contexts as part of Open_tables_state
  context.  Also introduced THD::locked_tables_root memory root
  which is to be used for allocating MDL_LOCK objects for tables in
  LOCK TABLES statement (end of lifetime for such objects is UNLOCK
  TABLES so we can't use statement or execution root for them).
  
  Note: handler_mdl_context and locked_tables_root and
  mdl_el_root will be removed by subsequent patches.
sql/sql_db.cc:
  mysql_rm_db() does not really need to call remove_db_from_cache()
  as it drops each table in the database using
  mysql_rm_table_part2(), which performs all necessary operations on
  table (definition) cache.
sql/sql_delete.cc:
  Use the new metadata locking API for TRUNCATE.
sql/sql_handler.cc:
  Changed HANDLER implementation to use new metadata locking
  subsystem.  Note that MDL_LOCK objects for HANDLER tables are
  allocated in the same chunk of heap memory as TABLE_LIST object
  for those tables.
sql/sql_insert.cc:
  mysql_insert():
    find_locked_table() now takes head of list of TABLE object as
    its argument instead of always scanning through THD::open_tables
    list.
  handle_delayed_insert():
    Allocate metadata lock request object for table open by delayed
    insert thread on execution memroot.  create_table_from_items():
    We no longer allocate dummy TABLE objects for tables being
    created if they don't exist. As consequence
    reopen_name_locked_table() no longer has link_in argument.
    open_table() now has one more argument which is not relevant for
    temporary tables.
sql/sql_parse.cc:
  - Moved unlock_locked_tables() routine to sql_base.cc and made
    available it in other files. Got rid of some redundant code by
    using this function.
  - Replaced boolean TABLE_LIST::create member with enum
    open_table_type member.
  - Use special memory root for allocating MDL_LOCK objects for
    tables open and locked by LOCK TABLES (these object should live
    till UNLOCK TABLES so we can't allocate them on statement nor
    execution memory root). Also properly set metadata lock
    upgradability attribure for those tables.
  - Under LOCK TABLES it is no longer allowed to flush tables which
    are not write-locked as this breaks metadata locking protocol
    and thus potentially might lead to deadlock.
  - Added auxiliary adjust_mdl_locks_upgradability() function.
sql/sql_partition.cc:
  Adjusted code to the fact that reopen_tables() no longer has
  "mark_share_as_old" argument. Got rid of comments which are no
  longer true.
sql/sql_plist.h:
  Added I_P_List template class for parametrized intrusive doubly
  linked lists and I_P_List_iterator for corresponding iterator.
  Unlike for I_List<> list elements of such list can participate in
  several lists. Unlike List<> such lists are doubly-linked and
  intrusive.
sql/sql_plugin.cc:
  Allocate metadata lock requests objects (MDL_LOCK) on execution
  memory root in cases when we use stack TABLE_LIST objects to open
  tables.
sql/sql_prepare.cc:
  Replaced boolean TABLE_LIST::create member with enum
  open_table_type member.  This allows easily handle situation in
  which instead of opening the table we want only to take exclusive
  metadata lock on it.
sql/sql_rename.cc:
  Use new metadata locking subsystem in implementation of RENAME
  TABLE.
sql/sql_servers.cc:
  Allocate metadata lock requests objects (MDL_LOCK) on execution
  memory root in cases when we use stack TABLE_LIST objects to open
  tables. Got rid of redundant code by using unlock_locked_tables()
  function.
sql/sql_show.cc:
  Acquire shared metadata lock when we are getting information for
  I_S table directly from TABLE_SHARE without doing full-blown table
  open.  We use high priority lock request in this situation in
  order to avoid deadlocks.
  Also allocate metadata lock requests objects (MDL_LOCK) on
  execution memory root in cases when TABLE_LIST objects are also
  allocated there
sql/sql_table.cc:
  mysql_rm_table():
    Removed comment which is no longer relevant.
  mysql_rm_table_part2():
    Now caller of mysql_ha_rm_tables() should not own LOCK_open.
    Adjusted code to use new metadata locking subsystem instead of
    name-locks.
  lock_table_name_if_not_cached():
    Moved this function from sql_base.cc to this file and
    reimplemented it using metadata locking API.
  mysql_create_table():
    Adjusted code to use new MDL API.
  wait_while_table_is_used():
    Changed function to use new MDL subsystem. Made thread waiting
    in it killable (this also led to introduction of return value so
    caller can distinguish successful executions from situations
    when waiting was aborted).
  close_cached_tables():
    Thread waiting in this function is killable now. As result it
    has return value for distinguishing between succes and failure.
    Got rid of redundant boradcast_refresh() call.
  prepare_for_repair():
    Use MDL subsystem instead of name-locks.
  mysql_admin_table():
    mysql_ha_rm_tables() now always assumes that caller doesn't own
    LOCK_open.
  mysql_repair_table():
    We should mark all elements of table list as requiring
    upgradable metadata locks.
  mysql_create_table_like():
    Use new MDL subsystem instead of name-locks.
  create_temporary_tables():
    We don't need to obtain metadata locks when creating temporary
    table.
  mysql_fast_or_online_alter_table():
    Thread waiting in wait_while_table_is_used() is now killable.
  mysql_alter_table():
    Adjusted code to work with new MDL subsystem and to the fact
    that threads waiting in what_while_table_is_used() and
    close_cached_table() are now killable.
sql/sql_test.cc:
  We no longer have separate table cache. TABLE instances are now
  associated with/linked to TABLE_SHARE objects in table definition
  cache.
sql/sql_trigger.cc:
  Adjusted code to work with new metadata locking subsystem.  Also
  reopen_tables() no longer has mark_share_as_old argument (Instead
  of relying on this parameter and related behavior FLUSH TABLES
  WITH READ LOCK now takes global shared metadata lock).
sql/sql_udf.cc:
  Allocate metadata lock requests objects (MDL_LOCK) on execution
  memory root in cases when we use stack TABLE_LIST objects to open
  tables.
sql/sql_update.cc:
  Adjusted code to work with new meta-data locking subsystem.
sql/sql_view.cc:
  Added proper meta-data locking to implementations of
  CREATE/ALTER/DROP VIEW statements. Now we obtain exclusive
  meta-data lock on a view before creating/ changing/dropping it.
  This ensures that all concurrent statements that use this view
  will finish before our statement will proceed and therefore we
  will get correct order of statements in the binary log.
  Also ensure that TABLE_LIST::mdl_upgradable attribute is properly
  propagated for underlying tables of view.
sql/table.cc:
  Added auxiliary alloc_mdl_locks() function for allocating metadata
  lock request objects for all elements of table list.
sql/table.h:
  TABLE_SHARE:
    Got rid of unused members. Introduced members for storing lists
    of used and unused TABLE objects for this share.
  TABLE:
    Added members for linking TABLE objects into per-share lists of
    used and unused TABLE instances. Added member for holding
    pointer to metadata lock for this table.
  TABLE_LIST:
    Replaced boolean TABLE_LIST::create member with enum
    open_table_type member.  This allows easily handle situation in
    which instead of opening the table we want only to take
    exclusive meta-data lock on it (we need this in order to handle
    ALTER VIEW and CREATE VIEW statements).
    Introduced new mdl_upgradable member for marking elements of
    table list for which we need to take upgradable shared metadata
    lock instead of plain shared metadata lock.  Added pointer for
    holding pointer to MDL_LOCK for the table.
  Added auxiliary alloc_mdl_locks() function for allocating metadata
  lock requests objects for all elements of table list.  Added
  auxiliary set_all_mdl_upgradable() function for marking all
  elements in table list as requiring upgradable metadata locks.
storage/myisammrg/ha_myisammrg.cc:
  Allocate MDL_LOCK objects for underlying tables of MERGE table.
  To be reworked once Ingo pushes his patch for WL4144.

> ------------------------------------------------------------
> revno: 3184.3.13
> revision-id: joro@sun.com-20091019135504-e6fmhf4xyy0wdymb
> parent: joro@sun.com-20091026095557-euhe1z9oxtgkw35h
> committer: Georgi Kodinov <joro@sun.com>
> branch nick: B47788-5.1-bugteam
> timestamp: Mon 2009-10-19 16:55:04 +0300
> message:
>   Bug #47788: Crash in TABLE_LIST::hide_view_error on 
>     UPDATE + VIEW + SP + MERGE + ALTER
>   
>   When cleaning up the stored procedure's internal 
>   structures the flag to ignore the errors for 
>   INSERT/UPDATE IGNORE was not cleaned up.
>   As a result error ignoring was on during name 
>   resolution. And this is an abnormal situation : the
>   SELECT_LEX flag can be on only during query execution.
>   
>   Fixed by correctly cleaning up the SELECT_LEX flag 
>   when reusing the SELECT_LEX in a second execution.

-------------------------------------------------------------
revno: 2877
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 35164-6.0
timestamp: Wed 2008-10-15 19:53:18 -0300
message:
Bug#35164: Large number of invalid pthread_attr_setschedparam calls
Bug#37536: Thread scheduling causes performance degradation at low thread count
Bug#12702: Long queries take 100% of CPU and freeze other applications under Windows

The problem is that although having threads with different priorities
yields marginal improvements [1] in some platforms [2], relying on some
statically defined priorities (QUERY_PRIOR and WAIT_PRIOR) to play well
(or to work at all) with different scheduling practices and disciplines
is, at best, a shot in the dark as the meaning of priority values may
change depending on the scheduling policy set for the process.

Another problem is that increasing priorities can hurt other concurrent
(running on the same hardware) applications (such as AMP) by causing
starvation problems as MySQL threads will successively preempt lower
priority processes. This can be evidenced by Bug#12702.

The solution is to not change the threads priorities and rely on the
system scheduler to perform its job. This also enables a system admin
to increase or decrease the scheduling priority of the MySQL process,
if intended.

Furthermore, the internal wrappers and code for changing the priority
of threads is being removed as they are now unused and ancient.

1. Due to unintentional side effects. On Solaris this could artificially
help benchmarks as calling the priority changing syscall millions of
times is more beneficial than the actual setting of the priority.

2. Where it actually works. It has never worked on Linux as the default
scheduling policy SCHED_OTHER only accepts the static priority 0.


configure.in:
  Remove checks for functions that are not used anymore.
include/config-netware.h:
  Remove unused define.
include/my_pthread.h:
  Remove thread priority changing wrappers.
mysys/my_pthread.c:
  Remove thread priority changing wrappers. They do not work properly
  and their implementations were incorrectly protected by a check for
  HAVE_PTHREAD_SETSCHEDPARAM.
mysys/thr_alarm.c:
  Remove meaningless (100) increase of a thread priority.
sql/mysql_priv.h:
  Remove meaningless thread priority values.
sql/mysqld.cc:
  Don't change thread priorities.
sql/slave.cc:
  Don't change thread priorities.
sql/slave.h:
  Update function prototype.
sql/sql_parse.cc:
  Don't change thread priorities.
sql/sql_prepare.cc:
  Don't change thread priorities.
sql/unireg.h:
  Mark flag as obsolete.
storage/innobase/handler/ha_innodb.cc:
  Remove use of obsolete flag and associated behavior.
storage/innobase/include/srv0srv.h:
  Remove use of obsolete flag and associated variables.
storage/innobase/os/os0thread.c:
  Remove use of obsolete flag and associated behavior.
storage/innobase/srv/srv0srv.c:
  Remove use of obsolete flag and associated variables.