diagnostics.  This was written in order to better track down
Issue #313 in InnoDB Hot Backup.

MLOG_LSN: A new redo log entry type, for recording the current log
sequence number (LSN).  This will be checked in an assertion in
recv_parse_log_rec().

rb://161, discussed with Sunny and Vasil.

Since r5872, the InnoDB Hot Backup build was broken.
Fix it by not defining any thread synchronization primitives in ut0ut.h.
InnoDB Hot Backup is a single-threaded program.

for https://svn.innodb.com/svn/hotbackup/branches/3.5

UNIV_SYNC_DEBUG is defined.

sync_thread_levels_g(): Add the parameter "warn".  Do not print
anything unless it is set.

sync_thread_add_level(): Pass warn=TRUE to sync_thread_levels_g()
when the check is within an assertion; FALSE if it is not.

In case of pages that are not made young the counter is incremented
only when the page in question is 'old'. In case of pages that are
made young the counter is incremented in case of all pages. For apple
to apple comparison this patch changes the 'young-making' counter to
consider only 'old' blocks.

Approved by: Marko

Add missing return statement in the test program that could have
caused a warning.

Back-merge c5880 and c5881 from branches/embedded-1.0:

  ------------------------------------------------------------------------
  r5880 | vasil | 2009-09-12 17:28:44 +0300 (Sat, 12 Sep 2009) | 18 lines
  Changed paths:
     M /branches/embedded-1.0/configure.in
     M /branches/embedded-1.0/include/os0sync.h
     M /branches/embedded-1.0/srv/srv0start.c
  
  branches/embedded-1.0:
  
  Clean up and simplify the code that surrounds the atomic ops:
  
  * Simplify the code that prints what atomics are used:
  Instead of repeating the same conditions on which each atomics are used
  use just one printf that prints a variable defined by the code which
  chooses what atomics to use.
  
  * In os0sync.h pick up each atomic variant only if it has been selected
  by autoconf (based on IB_ATOMIC_MODE_* macros). Define the startup message
  to be printed.
  
  * In configure.in: check what user has chosen and if he has chosen
  something that is not available, emit an error. If nothing has been chosen
  explicitly by the user, auto select an option according to the described
  logic in configure.in.
  
  ------------------------------------------------------------------------
  r5881 | vasil | 2009-09-12 20:08:27 +0300 (Sat, 12 Sep 2009) | 4 lines
  Changed paths:
     M /branches/embedded-1.0/configure.in
  
  branches/embedded-1.0:
  
  Fix syntax error in test program.
  
  ------------------------------------------------------------------------

Remove unnecessary macro.

Explicitly include os0sync.h to the places where HAVE_ATOMIC_BUILTINS and
INNODB_RW_LOCKS_USE_ATOMICS are used to avoid potential problems.

Rename HAVE_SOLARIS_ATOMICS to HAVE_IB_SOLARIS_ATOMICS and 
IB_HAVE_PAUSE_INSTRUCTION to HAVE_IB_PAUSE_INSTRUCTION so they
all follow the same HAVE_IB_* convention.

Define HAVE_ATOMIC_BUILTINS and INNODB_RW_LOCKS_USE_ATOMICS in os0sync.h
instead of in univ.i. The code expects os_*() macros to be present if
HAVE_ATOMIC_BUILTINS and INNODB_RW_LOCKS_USE_ATOMICS are defined. So define
them next to defining the os_*() macros.

Include ut0auxconf.h only if none of the macros it would define is defined.
The check when to include this header was outdated from the time when there
was only one macro involved.

Move the atomics checks that are in univ.i outside of
#if windows ... #else ... #endif
This simplifies the code and removes some duplicates like defining
HAVE_ATOMIC_BUILTINS if HAVE_WINDOWS_ATOMICS is defined in both branches.

Do not define the same macro HAVE_ATOMIC_PTHREAD_T for different events.
Instead define HAVE_IB_ATOMIC_PTHREAD_T_GCC and
HAVE_IB_ATOMIC_PTHREAD_T_SOLARIS.

Move the check whether to include ut0auxconf.h before everything because
we are now even checking for GCC atomics, we relied on MySQL to define
this macro before.

Update comment to reflect reality.

Add the check for GCC atomics to ut0auxconf* (copied from plug.in) because
we no longer rely on MySQL's HAVE_GCC_ATOMIC_BUILTINS.

Simplify the compile time checks by splittig them into 5 independent checks:

* Whether GCC atomics are available
* Whether pthread_t can be used by GCC atomics
* Whether Solaris libc atomics are available
* Whether pthread_t can be used by Solaris libs atomics
* Checking the size of pthread_t

Include string.h which is needed for memset().

Check that pthread_t can indeed be passed to Solaris atomic functions, instead
of assuming that it can be passed if 0 can be assigned to it. It could be that:
* 0 can be assigned, but pthread_t cannot be passed and
* 0 cannot be assigned but pthread_t can be passed

Better to check what we are interested in, not something else and make
assumptions.

Fix the indentation of the closing bracket.

dropping incomplete indexes (Issue #337).

trx_rollback_or_clean_recovered(ibool all): New function, split from
trx_rollback_or_clean_all_recovered().  all==FALSE will only roll back
dictionary transactions.

recv_recovery_from_checkpoint_finish(): Call
trx_rollback_or_clean_recovered(FALSE) before
row_merge_drop_temp_indexes().

rb://158 approved by Sunny Bains

addressing Bug #45015 (Issue #316), in r5703.

buf_page_set_accessed_make_young(): New auxiliary function, called by
buf_page_get_zip(), buf_page_get_gen(),
buf_page_optimistic_get_func(). Call ut_time_ms() outside of
buf_pool_mutex. Use cached access_time.

buf_page_set_accessed(): Add the parameter time_ms, so that
ut_time_ms() need not be called while holding buf_pool_mutex.

buf_page_optimistic_get_func(), buf_page_get_known_nowait(): Read
buf_page_t::access_time without holding buf_pool_mutex. This should be
OK, because the field is only used for heuristic purposes.

buf_page_peek_if_too_old(): If buf_pool->freed_page_clock == 0, return
FALSE, so that we will not waste time moving blocks in the LRU list in
the warm-up phase or when the workload fits in the buffer pool.

rb://156 approved by Sunny Bains

HA_ERR_TOO_MANY_CONCURRENT_TRXS is added in 5.1.38.
But the plugin should still work with previous versions
of MySQL.

Fix a bug in manipulating the variable innodb_old_blocks_pct:

for any value assigned it got that value -1, except for 75. When
assigned 75, it got 75.

  mysql> set global innodb_old_blocks_pct=15;
  Query OK, 0 rows affected (0.00 sec)
  
  mysql> show variables like 'innodb_old_blocks_pct';
  +-----------------------+-------+
  | Variable_name         | Value |
  +-----------------------+-------+
  | innodb_old_blocks_pct | 14    | 
  +-----------------------+-------+
  1 row in set (0.00 sec)
  
  mysql> set global innodb_old_blocks_pct=75;
  Query OK, 0 rows affected (0.00 sec)
  
  mysql> show variables like 'innodb_old_blocks_pct';
  +-----------------------+-------+
  | Variable_name         | Value |
  +-----------------------+-------+
  | innodb_old_blocks_pct | 75    | 
  +-----------------------+-------+

After the fix it gets exactly what was assigned.

Approved by:	Marko (via IM)

that was introduced in r5779 on 32-bit systems.

buf_pool->freed_page_clock is wider than 32 bits.

together with buf_LRU_get_recent_limit().

The changes are non-functional changes for normal InnoDB,
but needed for building the Hot Backup on Windows (with
UNIV_HOTBACKUP defined).

- Define os_aio_use_native_aio for HB.
- Do not acquire seek mutexes for backup since HB is single threaded.
- Do not use srv_flush_log_at_trx_commit for HB build

rb://155

Approved by: Marko

to the compressed page, if there is one.  Previously, the function only
wrote the LSN to the uncompressed page.

It is not clear why recv_recover_page_func() is updating FIL_PAGE_LSN
in the buffer pool.  The log sequence number will be stamped on the
page when it is flushed to disk, in buf_flush_init_for_writing().
I noticed this inconsistency when analyzing Issue #313, but this patch
does not fix it.  That is no surprise, since FIL_PAGE_LSN should only
matter on disk files, not in the buffer pool.

that was triggered when creating an index on an empty table.

row_merge_sort(): Add debug assertions and comments that justify
the loop termination condition.

The bogus assertion ut_ad(ihalf > 0) was reported by Michael.

because the termination condition will always hold on the first iteration.

in a local variable.

Add const qualifiers.

output parameter "success".
Success is also indicated by a nonzero return value.