detector". This patch addresses performance regression in OLTP_RO/MyISAM
test on Windows introduced by the fix for bug #56405. Thus it makes
original patch acceptable as a solution for bug #56585 "Slowdown of
readonly sysbench benchmarks (e.g point_select) on Windows 5.5".

With this patch, MySQL will use native Windows condition variables and 
reader-writer locks  if  they are supported by the OS.

This speeds up MyISAM and the effect comes mostly from using native
rwlocks. Native conditions improve scalability with higher number of 
concurrent users in other situations, e.g for prlocks.

Benchmark numbers for this patch as measured on Win2008R2 quad
core machine are attached to the bug report.
( direct link http://bugs.mysql.com/file.php?id=15883 )

Note that currently we require at least Windows7/WS2008R2 for 
reader-writer locks, even though native rwlock is available also on Vista.
Reason is that "trylock" APIs are missing on Vista, and trylock is used in
the server (in a single place in query cache).

While this patch could have been written differently, to enable the native
rwlock optimization also on Vista/WS2008 (e.g using native locks everywhere
but portable implementation in query cache), this would come at the 
expense of the code clarity, as it would introduce a new  "try-able" rwlock
type, to handle Vista case.

Another way to improve performance for the special case 
(OLTP_RO/MYISAM/Vista) would be to eliminate "trylock" usage from server,
 but this is outside of the scope here.


Native conditions variables are used beginning with Vista though the effect
of using condition variables alone is not measurable in this benchmark.
But when used together with native rwlocks on Win7, native conditions improve 
performance in high-concurrency OLTP_RO/MyISAM (128 and more sysbench 
users).

conflicts:
   conflict      dbug/dbug.c
   conflict      sql/sql_load.cc

This is a null merge because it only contains InnoDB changes that
originated in mysql-5.1-innodb and have been manually ported into
mysql-5.5-innodb.

This is a manual merge from mysql-5.1-innodb of:

  revision-id: vasil.dimov@oracle.com-20100930102618-s9f9ytbytr3eqw9h
  committer: Vasil Dimov <vasil.dimov@oracle.com>
  timestamp: Thu 2010-09-30 13:26:18 +0300
  message:
    Fix a potential bug when using __sync_lock_test_and_set()

    TYPE __sync_lock_test_and_set (TYPE *ptr, TYPE value, ...)

    it is not documented what happens if the two arguments are of different
    type like it was before: the first one was lock_word_t (byte) and the
    second one was 1 or 0 (int).

    Approved by:	Marko (via IRC)

LOAD DATA into partitioned MyISAM table

Problem was that both partitioning and myisam
used the same table_share->mutex for different protections
(auto inc and repair).

Solved by adding a specific mutex for the partitioning
auto_increment.

Also adding destroying the ha_data structure in
free_table_share (which is to be propagated
into 5.5).

This is a 5.1 ONLY patch, already fixed in 5.5+.

           REBUILD PARTITION under LOCK TABLE

Collapsed patch including updates from the reviews.

In case of failure in ALTER ... PARTITION under LOCK TABLE
the server could crash, due to it had modified the locked
table object, which was not reverted in case of failure,
resulting in a bad table definition used after the failed
command.

Solved by instead of altering the locked table object and
its partition_info struct, creating an internal temporary
intermediate table object used for altering,
just like the non partitioned mysql_alter_table.
So if an error occur before the alter operation is complete,
the original table is not modified at all.
But if the alter operation have succeeded so far that it
must be completed as whole,
the table is properly closed and reopened.
(The completion on failure is done by the ddl_log.)

This is a manual merge from mysql-5.1-innodb of:

  revno: 3618
  revision-id: vasil.dimov@oracle.com-20100930124844-yglojy7c3vaji6dx
  parent: vasil.dimov@oracle.com-20100930102618-s9f9ytbytr3eqw9h
  committer: Vasil Dimov <vasil.dimov@oracle.com>
  branch nick: mysql-5.1-innodb
  timestamp: Thu 2010-09-30 15:48:44 +0300
  message:
    Fix Bug#56340 innodb updates index stats too frequently after non-index updates

    This is a simple optimization issue. All stats are related to only indexed
    columns, index size or number of rows in the whole table. UPDATEs that touch
    only non-indexed columns cannot affect stats and we can avoid calling the
    function row_update_statistics_if_needed() which may result in unnecessary I/O.

    Approved by:	Marko (rb://466)

In addition to the above message: we know that
row_update_cascade_for_mysql() (the other place where
row_update_statistics_if_needed is called) always updates indexed
columns (FK-related), so there is no need to add this cond there.

Bug#57113: ha_partition::extra(ha_extra_function):
            Assertion `m_extra_cache' failed

Fix for bug#55458 included DBUG_ASSERTS causing
debug builds of the server to crash on
another multi-table update.

Removed the asserts since they where wrong.
(updated after testing the patch in 5.5).

inline perl in the test.

in the MDL deadlock detector".

It is no longer needed as a better fix for this bug has
been pushed.

This is a simple optimization issue. All stats are related to only indexed
columns, index size or number of rows in the whole table. UPDATEs that touch
only non-indexed columns cannot affect stats and we can avoid calling the
function row_update_statistics_if_needed() which may result in unnecessary I/O.

Approved by:	Marko (rb://466)

TYPE __sync_lock_test_and_set (TYPE *ptr, TYPE value, ...)

it is not documented what happens if the two arguments are of different
type like it was before: the first one was lock_word_t (byte) and the
second one was 1 or 0 (int).

Approved by:	Marko (via IRC)

detector" that doesn't introduce bug #56715 "Concurrent
transactions + FLUSH result in sporadical unwarranted
deadlock errors".

Deadlock could have occurred when workload containing a mix
of DML, DDL and FLUSH TABLES statements affecting the same
set of tables was executed in a heavily concurrent environment.

This deadlock occurred when several connections tried to
perform deadlock detection in the metadata locking subsystem.
The first connection started traversing wait-for graph,
encountered a sub-graph representing a wait for flush, acquired
LOCK_open and dived into sub-graph inspection. Then it
encountered sub-graph corresponding to wait for metadata lock
and blocked while trying to acquire a rd-lock on
MDL_lock::m_rwlock, since some,other thread had a wr-lock on it.
When this wr-lock was released it could have happened (if there
was another pending wr-lock against this rwlock) that the rd-lock
from the first connection was left unsatisfied but at the same
time the new rd-lock request from the second connection sneaked
in and was satisfied (for this to be possible the second
rd-request should come exactly after the wr-lock is released but
before pending the wr-lock manages to grab rwlock, which is
possible both on Linux and in our own rwlock implementation).
If this second connection continued traversing the wait-for graph
and encountered a sub-graph representing a wait for flush it tried
to acquire LOCK_open and thus the deadlock was created.

The previous patch tried to workaround this problem by not
allowing the deadlock detector to lock LOCK_open mutex if
some other thread doing deadlock detection already owns it
and current search depth is greater than 0. Instead deadlock
was reported. As a result it has introduced bug #56715.

This patch solves this problem in a different way.
It introduces a new rw_pr_lock_t implementation to be used
by MDL subsystem instead of one based on Linux rwlocks or
our own rwlock implementation. This new implementation
never allows situation in which an rwlock is rd-locked and
there is a blocked pending rd-lock. Thus the situation which
has caused this bug becomes impossible with this implementation.

Due to fact that this implementation is optimized for
wr-lock/unlock scenario which is most common in the MDL
subsystem it doesn't introduce noticeable performance
regressions in sysbench tests. Moreover it significantly
improves situation for POINT_SELECT test when many
connections are used.

No test case is provided as this bug is very hard to repeat
in MTR environment but is repeatable with the help of RQG
tests.
This patch also doesn't include a test for bug #56715
"Concurrent transactions + FLUSH result in sporadical
unwarranted deadlock errors" as it takes too much time to
be run as part of normal test-suite runs.

with CMake 2.8.3 builtin macro

This patch moves the regression test from variables.test to
variables_debug.test as the debug system variable is not 
available on release builds.