for compressed InnoDB tables

ha_innodb::info_low(): For calculating data_length or index_length,
use the compressed page size for compressed tables instead of UNIV_PAGE_SIZE.

rb:714 approved by Sunny Bains

BUG #11754979 - 46675: ON DUPLICATE KEY UPDATE AND UPDATECOUNT() POSSIBLY WRONG 

The mysql_affected_rows() client call returns 3 instead of 2 on
INSERT ... ON DUPLICATE KEY UPDATE query with a duplicated key value.

The fix for the old bug #29692 was incomplete: unnecessary double
increment of "touched" rows still happened.

This bugfix removes:
1) unneeded increment of "touched" rows and
2) useless double resetting of auto-increment value.

There is an optimization of DISTINCT in JOIN::optimize()
which depends on THD::used_tables value. Each SELECT statement
inside SP resets used_tables value(see mysql_select()) and it
leads to wrong result. The fix is to replace THD::used_tables
with LEX::used_tables.

The problem is that TIME_FUZZY_DATE is explicitly used for get_arg0_date()
function in Item_date_typecast::get_date method. The fix is to use real
fuzzy_date value.

In 5.5, REFRESH SLAVE is used as an alias for RESET SLAVE and
was removed in 5.6. Reseting a slave through REFRESH SLAVE was
causing errors in the valgrind platform since reset_slave_info
was undefined.

To fix the problem, we have set reset_slave_info while calling
REFRESH SLAVE.

WITH UTF32

The 5.5 version of the UTF32 collation was not enforcing the BMP range that 
it currently supports when comparing with LIKE. 
Fixed by backporting the checks for the BMP from trunk.
Added a named constant for the maximum character that can have a weight
in the weight table.

SHOW ALL PROBLEMS FOR MERGE TABLE COMPLIANCE IN 5.1".

The problem was that CHECK/REPAIR TABLE for a MERGE table which
had several children missing or in wrong engine reported only
issue with the first such table in its result-set. While in 5.0
this statement returned the whole list of problematic tables.

Ability to report problems for all children was lost during
significant refactorings of MERGE code which were done as part
of work on 5.1 and 5.5 releases.

This patch restores status quo ante refactorings by changing
code in such a way that:
1) Failure to open child table due to its absence during CHECK/
   REPAIR TABLE for a MERGE table is not reported immediately
   when its absence is discovered in open_tables(). Instead
   handling/error reporting in such a situation is postponed
   until the moment when children are attached.
2) Code performing attaching of children no longer stops when
   it encounters first problem with one of the children during
   CHECK/REPAIR TABLE. Instead it continues iteration through
   the child list until all problems caused by child absence/
   wrong engine are reported.

Note that even after this change problem with mismatch of
child/parent definition won't be reported if there is also
another child missing, but this is how it was in 5.0 as well.

TOOLS

Backport a fix for Bug 57094 from 5.5.
The following revision was backported:

# revision-id: alexander.nozdrin@oracle.com-20101006150613-ls60rb2tq5dpyb5c
# parent: bar@mysql.com-20101006121559-am1e05ykeicwnx48
# committer: Alexander Nozdrin <alexander.nozdrin@oracle.com>
# branch nick: mysql-5.5-bugteam-bug57094
# timestamp: Wed 2010-10-06 19:06:13 +0400
# message:
#   Fix for Bug 57094 (Copyright notice incorrect?).
#   
#   The fix is to:
#     - introduce ORACLE_WELCOME_COPYRIGHT_NOTICE define to have a single place
#       to specify copyright notice;
#     - replace custom copyright notices with ORACLE_WELCOME_COPYRIGHT_NOTICE
#       in programs.

             FUNCTION 'PTHREAD_INIT' 

The problem was that compilation would fail with a warning:
Implicit declaration of function 'pthread_init' if MySQL was
compiled on OS X 10.7 (Lion). The reason was that pthread_init()
is now part of an internal OS X pthread library so it was found
by CMake.

This patch fixes the problem by removing HAVE_PTHREAD_INIT and
related code. pthread_init() was specific to MIT-pthreads which
has not been supported since 4.1 and was therefore no longer
relevant.

No test case added.

The title of the bug is a little confusing. The actual fix is to
reintroduce random readahead inside InnoDB with a dynamic, global
switch innodb_random_read_ahead [default = off].

Approved by: Sunny Bains
rb://696

Before BUG#28796, an empty host was used to identify that an instance was no
longer a slave. However, BUG#28796 changed this behavior and one cannot set
an empty host. Besides, a RESET SLAVE only cleans up information on the next
event to retrieve from the master, disables ssl and resets heartbeat period.
So a call to SHOW SLAVE STATUS after issuing a RESET SLAVE still returns some
valid information, such as host, port, user and password.

To fix this problem, we have introduced the command RESET SLAVE ALL that does
what a regular RESET SLAVE does and also clears host, port, user and password
information thus allowing users to identify when an instance is no longer a
slave.

Truncate result of decimal division before converting to integer.

Turns out the DBUG_ASSERT added by fix for Bug#11792200 was overly pessimistic:
'stop0' is used in the main loop of do_div_mod, but we only dereference 'buf0'
for div operations, not for mod.