Fixed a memory leak found by valgrind. The memory leak was
a result of JOINs corresponding to subselects in a global
ORDER BY of a UNION not being cleaned up because the
fake_select of the UNION didn't point down to the subquery
select.

Registration of pointer change if we assign it to other pointer which should be identical after statement execution (PS/SP).

mysql-test/r/subselect.result:
  Test suite.
mysql-test/t/subselect.test:
  Test suite.
sql/sql_class.cc:
  The procedure of the pointer registration.
sql/sql_class.h:
  The procedure of the pointer registration.
sql/sql_lex.cc:
  Registration of pointer change if we assign it to other pointer which should be identical after statement execution (PS/SP).

Improved handling of EXPLAIN statements for subqueries.
This patch specifically solves the problem when EXPLAIN reports:
  "const row not found"
instead of
  "no matching row in const table".

  Phase 3: Implementation of re-optimization of subqueries with injected predicates
           and cost comparison between Materialization and IN->EXISTS strategies.

The commit contains the following known problems:
- The implementation of EXPLAIN has not been re-engineered to reflect the
  changes in subquery optimization. EXPLAIN for subqueries is called during
  the execute phase, which results in different code paths during JOIN::optimize
  and thus in differing EXPLAIN messages for constant/system tables.
- There are some valgrind warnings that need investigation
- Several EXPLAINs with minor differences need to be reconsidered after fixing
  the EXPLAIN problem above.

This patch also adds one extra optimizer_switch: 'in_to_exists' for complete
manual control of the subquery execution strategies.

  
Reset correctly the LIMIT and the uncacheable flag of a subquery when executing
it via materialization.

Fixes for multiple problems/bugs/test failures that resulted from moving
subquery optimization from the execution phase to the optimization phase.

Fix compiler warnings.

mysys/stacktrace.c:
  Tag unused parameters.
sql/sql_lex.cc:
  Variable becomes unused in non-debug builds. Also, no need to
  assert the obvious.

/*![:version:] Query Code */, where [:version:] is a sequence of 5 
digits representing the mysql server version(e.g /*!50200 ... */),
is a special comment that the query in it can be executed on those 
servers whose versions are larger than the version appearing in the 
comment. It leads to a security issue when slave's version is larger 
than master's. A malicious user can improve his privileges on slaves. 
Because slave SQL thread is running with SUPER privileges, so it can
execute queries that he/she does not have privileges on master.

This bug is fixed with the logic below: 
- To replace '!' with ' ' in the magic comments which are not applied on
  master. So they become common comments and will not be applied on slave.

- Example:
  'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /*!99999 ,(3)*/
  will be binlogged as
  'INSERT INTO t1 VALUES (1) /*!10000, (2)*/ /* 99999 ,(3)*/

mysql-test/suite/rpl/t/rpl_conditional_comments.test:
  Test the patch for this bug.
sql/mysql_priv.h:
  Rename inBuf as rawBuf and remove the const limitation.
sql/sql_lex.cc:
  To replace '!' with ' ' in the magic comments which are not applied on
  master.
sql/sql_lex.h:
  Remove the const limitation on parameter buff, as it can be modified in the function since
  this patch.
  Add member function yyUnput for Lex_input_stream. It set a character back the query buff.
sql/sql_parse.cc:
  Rename inBuf as rawBuf and remove the const limitation.
sql/sql_partition.cc:
  Remove the const limitation on parameter part_buff, as it can be modified in the function since
  this patch.
sql/sql_partition.h:
  Remove the const limitation on parameter part_buff, as it can be modified in the function since
  this patch.
sql/table.h:
  Remove the const limitation on variable partition_info, as it can be modified since
  this patch.

There were two problems that caused wrong results reported with this bug.
1. In some cases stored(persistent) virtual columns were not marked
in the write_set and in the vcol_set bitmaps.
2. If the list of fields in an insert command was empty then the values of
the stored virtual columns were set to default.

To fix the first problem the function st_table::mark_virtual_columns_for_write
was modified. Now the function has a parameter that says whether the virtual 
columns are to be marked for insert or for update.  
To fix the second problem a special handling of empty insert lists is
added in the function fill_record().

libmysqld/Makefile.am:
  The new file added.
mysql-test/r/index_merge_myisam.result:
  subquery_cache optimization option added.
mysql-test/r/myisam_mrr.result:
  subquery_cache optimization option added.
mysql-test/r/subquery_cache.result:
  The subquery cache tests added.
mysql-test/r/subselect3.result:
  Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect3_jcl6.result:
  Subquery cache switched off to avoid changing read statistics.
mysql-test/r/subselect_no_mat.result:
  subquery_cache optimization option added.
mysql-test/r/subselect_no_opts.result:
  subquery_cache optimization option added.
mysql-test/r/subselect_no_semijoin.result:
  subquery_cache optimization option added.
mysql-test/r/subselect_sj.result:
  subquery_cache optimization option added.
mysql-test/r/subselect_sj_jcl6.result:
  subquery_cache optimization option added.
mysql-test/t/subquery_cache.test:
  The subquery cache tests added.
mysql-test/t/subselect3.test:
  Subquery cache switched off to avoid changing read statistics.
sql/CMakeLists.txt:
  The new file added.
sql/Makefile.am:
  The new files added.
sql/item.cc:
  Expression cache item (Item_cache_wrapper) added.
  Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item.h:
  Expression cache item (Item_cache_wrapper) added.
  Item_ref and Item_field fixed for correct usage of result field and fast resolwing in SP.
sql/item_cmpfunc.cc:
  Subquery cache added.
sql/item_cmpfunc.h:
  Subquery cache added.
sql/item_subselect.cc:
  Subquery cache added.
sql/item_subselect.h:
  Subquery cache added.
sql/item_sum.cc:
  Registration of subquery parameters added.
sql/mysql_priv.h:
  subquery_cache optimization option added.
sql/mysqld.cc:
  subquery_cache optimization option added.
sql/opt_range.cc:
  Fix due to subquery cache.
sql/opt_subselect.cc:
  Parameters of the function cahnged.
sql/procedure.h:
  .h file guard added.
sql/sql_base.cc:
  Registration of subquery parameters added.
sql/sql_class.cc:
  Option to allow add indeces to temporary table.
sql/sql_class.h:
  Item iterators added.
  Option to allow add indeces to temporary table.
sql/sql_expression_cache.cc:
  Expression cache for caching subqueries added.
sql/sql_expression_cache.h:
  Expression cache for caching subqueries added.
sql/sql_lex.cc:
  Registration of subquery parameters added.
sql/sql_lex.h:
  Registration of subqueries and subquery parameters added.
sql/sql_select.cc:
  Subquery cache added.
sql/sql_select.h:
  Subquery cache added.
sql/sql_union.cc:
  A new parameter to the function added.
sql/sql_update.cc:
  A new parameter to the function added.
sql/table.cc:
  Procedures to manage temporarty tables index added.
sql/table.h:
  Procedures to manage temporarty tables index added.
storage/maria/ha_maria.cc:
  Fix of handler to allow destoy a table in case of error during the table creation.
storage/maria/ha_maria.h:
  .h file guard added.
storage/myisam/ha_myisam.cc:
  Fix of handler to allow destoy a table in case of error during the table creation.

> ------------------------------------------------------------
> revno: 3362
> revision-id: davi.arnaut@sun.com-20100401131522-895y8uzvv8ag44gs
> parent: ramil@mysql.com-20100429045409-r7r5lcyiruis15v7
> committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
> branch nick: 50755-5.1
> timestamp: Thu 2010-04-01 10:15:22 -0300
> message:
>   Bug#50755: Crash if stored routine def contains version comments
>   
>   The problem was that a syntactically invalid trigger could cause
>   the server to crash when trying to list triggers. The crash would
>   happen due to a mishap in the backup/restore procedure that should
>   protect parser items which are not associated with the trigger. The
>   backup/restore is used to isolate the parse tree (and context) of
>   a statement from the load (and parsing) of a trigger. In this case,
>   a error during the parsing of a trigger could cause the improper
>   backup/restore sequence.
>   
>   The solution is to properly restore the original statement context
>   before the parser is exited due to syntax errors in the trigger body.

            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.

Bug #39022: completed
Bug #39653: reverted as invalid
Bug #45640: ameliorated, simplified, optimized
Bug #48483: completed
Bug #49324: improved
Bug #51242/52336: reverted, applied a real fix.

            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.

The problem was that a syntactically invalid trigger could cause
the server to crash when trying to list triggers. The crash would
happen due to a mishap in the backup/restore procedure that should
protect parser items which are not associated with the trigger. The
backup/restore is used to isolate the parse tree (and context) of
a statement from the load (and parsing) of a trigger. In this case,
a error during the parsing of a trigger could cause the improper
backup/restore sequence.

The solution is to properly restore the original statement context
before the parser is exited due to syntax errors in the trigger body.

mysql-test/r/trigger.result:
  Add test case result for Bug#50755
mysql-test/t/trigger.test:
  Add test case for Bug#50755
sql/sp_head.cc:
  Merge sp_head::destroy() and sp_head destructor. Retrieve THD
  from the LEX so that m_thd is not necessary.
sql/sql_lex.cc:
  Explicitly restore the original environment.

Add some extra error output and code cleanup in an attempt to fix/debug
a rare random testsuite problem in check_warnings, where the exit code
from mysqltest is somehow corrupted inside mysql-test-run.pl.

include/my_global.h:
  Fix compiler warnings on some platforms.
mysql-test/lib/My/SafeProcess.pm:
  Move dereference of $? subprocess exit code closer to where it is generated,
  to make the code more robust and on the chance that this will fix the
  occasional problems in check_warnings we see in Buildbot.
mysql-test/mysql-test-run.pl:
  When check_warnings failed, also log the mysqld server for which it failed.
sql/sql_lex.cc:
  Fix compiler warning about possibly uninitialised value, by rewriting a for()
  loop that is always executed at least once into a do .. while() loop with an
  assert.
sql/table.cc:
  Fix compiler warning about uninitialised value.
storage/federatedx/ha_federatedx.cc:
  Fix uninitialised variable.
storage/maria/ma_delete.c:
  Fix compiler warning about uninitialised value.
storage/maria/ma_loghandler.c:
  Fix compiler warning about uninitialised value.
storage/myisam/ft_stopwords.c:
  Fix compiler warning.
storage/myisam/mi_write.c:
  Fix compiler warning about possibly uninitialised value, by rewriting a while()
  loop that is always executed at least once into a do .. while() loop with an
  assert.
storage/xtradb/btr/btr0cur.c:
  Fix compiler warning about possibly uninitialised value.
support-files/compiler_warnings.supp:
  Fix warning suppression to cover all cases in yassl.
vio/viossl.c:
  Fix compiler warning.

- Variant #3 of the fix. It also
 = Unifies code with table elimination's 
 = is able to handle FROM-subquery pullout.

Grouping by a subquery in a query with a distinct aggregate
function lead to a wrong result (wrong and unordered
grouping values).

There are two related problems:

1) The query like this:

   SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) c
   FROM t1 GROUP BY aa

returned wrong result, because the outer reference "t1.a"
in the subquery was substituted with the Item_ref item.

The Item_ref item obtains data from the result_field object
that refreshes once after the end of each group. This data
is not applicable to filesort since filesort() doesn't care
about groups (and doesn't update result_field objects with
copy_fields() and so on). Also that data is not applicable
to group separation algorithm: end_send_group() checks every
record with test_if_group_changed() that evaluates Item_ref
items, but it refreshes those Item_ref-s only after the end
of group, that is a vicious circle and the grouped column
values in the output are shifted.

Fix: if
       a) we grouping by a subquery and
       b) that subquery has outer references to FROM list
          of the grouping query,
     then we substitute these outer references with
     Item_direct_ref like references under aggregate
     functions: Item_direct_ref obtains data directly
     from the current record.

2) The query with a non-trivial grouping expression like:

   SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) c
   FROM t1 GROUP BY aa+0

also returned wrong result, since JOIN::exec() substitutes
references to top-level aliases in SELECT list with Item_copy
caching items. Item_copy items have same refreshing policy
as Item_ref items, so the whole groping expression with
Item_copy inside returns wrong result in filesort() and
end_send_group().

Fix: include aliased items into GROUP BY item tree instead
     of Item_ref references to them.



mysql-test/r/group_by.result:
  Test case for bug #45640
mysql-test/t/group_by.test:
  Test case for bug #45640
sql/item.cc:
  Bug #45640: optimizer bug produces wrong results
  
  Item_field::fix_fields() has been modified to resolve
  aliases in GROUP BY item trees into aliased items instead
  of Item_ref items.
sql/item.h:
  Bug #45640: optimizer bug produces wrong results
  
  - Item::find_item_processor() has been introduced.
  - Item_ref::walk() has been modified to apply processors
    to itself too (not only to referenced item).
sql/mysql_priv.h:
  Bug #45640: optimizer bug produces wrong results
  
  fix_inner_refs() has been modified to accept group_list
  parameter.
sql/sql_lex.cc:
  Bug #45640: optimizer bug produces wrong results
  
  Initialization of st_select_lex::group_fix_field has
  been added.
sql/sql_lex.h:
  Bug #45640: optimizer bug produces wrong results
  
  The st_select_lex::group_fix_field field has been introduced
  to control alias resolution in Itef_fied::fix_fields.
sql/sql_select.cc:
  Bug #45640: optimizer bug produces wrong results
  
  - The fix_inner_refs function has been modified to treat
    subquery outer references like outer fields under aggregate
    functions, if they are included in GROUP BY item tree.
  
  - The find_order_in_list function has been modified to
    fix Item_field alias fields included in the GROUP BY item
    trees in a special manner.

- Backport into Maria DB 5.3, part 1

There are still test failures because of:
- Wrong query results in outer join + semi join
- EXPLAIN output differences

Removed compiler warnings

extra/libevent/epoll.c:
  Removed compiler warnings
extra/libevent/evbuffer.c:
  Removed compiler warnings
extra/libevent/event.c:
  Removed compiler warnings
extra/libevent/select.c:
  Removed compiler warnings
extra/libevent/signal.c:
  Removed compiler warnings
include/m_ctype.h:
  Define CHARSET_INFO, MY_CHARSET_HANDLER, MY_COLLATION_HANDLER, MY_UNICASE_INFO, MY_UNI_CTYPE and MY_UNI_IDX as const structures.
  Declare that pointers point to const data
include/m_string.h:
  Declare that pointers point to const data
include/my_sys.h:
  Redefine variables and function prototypes
include/mysql.h:
  Declare charset as const
include/mysql.h.pp:
  Declare charset as const
include/mysql/plugin.h:
  Declare charset as const
include/mysql/plugin.h.pp:
  Declare charset as const
mysys/charset-def.c:
  Charset can't be of type CHARSET_INFO as they are changed when they are initialized.
mysys/charset.c:
  Functions that change CHARSET_INFO must use 'struct charset_info_st'
  Add temporary variables to not have to change all_charsets[] (Which now is const)
sql-common/client.c:
  Added cast to const
sql/item_cmpfunc.h:
  Added cast to avoid compiler error.
sql/sql_class.cc:
  Added cast to const
sql/sql_lex.cc:
  Added cast to const
storage/maria/ma_ft_boolean_search.c:
  Added cast to avoid compiler error.
storage/maria/ma_ft_parser.c:
  Added cast to avoid compiler error.
storage/maria/ma_search.c:
  Added cast to const
storage/myisam/ft_boolean_search.c:
  Added cast to avoid compiler error
storage/myisam/ft_parser.c:
  Added cast to avoid compiler error
storage/myisam/mi_search.c:
  Added cast to const
storage/pbxt/src/datadic_xt.cc:
  Added cast to const
storage/pbxt/src/ha_pbxt.cc:
  Added cast to const
  Removed compiler warning by changing prototype of XTThreadPtr()
storage/pbxt/src/myxt_xt.h:
  Character sets should be const
storage/pbxt/src/xt_defs.h:
  Character sets should be const
storage/xtradb/btr/btr0cur.c:
  Removed compiler warning
strings/conf_to_src.c:
  Added const
  Functions that change CHARSET_INFO must use 'struct charset_info_st'
strings/ctype-big5.c:
  Made arrays const
strings/ctype-bin.c:
  Made arrays const
strings/ctype-cp932.c:
  Made arrays const
strings/ctype-czech.c:
  Made arrays const
strings/ctype-euc_kr.c:
  Made arrays const
strings/ctype-eucjpms.c:
  Made arrays const
strings/ctype-extra.c:
  Made arrays const
strings/ctype-gb2312.c:
  Made arrays const
strings/ctype-gbk.c:
  Made arrays const
strings/ctype-latin1.c:
  Made arrays const
strings/ctype-mb.c:
  Made arrays const
strings/ctype-simple.c:
  Made arrays const
strings/ctype-sjis.c:
  Made arrays const
strings/ctype-tis620.c:
  Made arrays const
strings/ctype-uca.c:
  Made arrays const
strings/ctype-ucs2.c:
  Made arrays const
strings/ctype-ujis.c:
  Made arrays const
strings/ctype-utf8.c:
  Made arrays const
strings/ctype-win1250ch.c:
  Made arrays const
strings/ctype.c:
  Made arrays const
  Added cast to const
  Functions that change CHARSET_INFO must use 'struct charset_info_st'
strings/int2str.c:
  Added cast to const

The original patch has been ameliorated by Sanja and Igor.

with gcc 4.3.2
      
This is the fifth patch cleaning up more GCC warnings about
variables used before initialized using the new macro
UNINIT_VAR().

The problem is that the lexer could inadvertently skip over the
end of a query being parsed if it encountered a malformed multibyte
character. A specially crated query string could cause the lexer
to jump up to six bytes past the end of the query buffer. Another
problem was that the laxer could use unfiltered user input as
a signed array index for the parser maps (having upper and lower
bounds 0 and 256 respectively).

The solution is to ensure that the lexer only skips over well-formed
multibyte characters and that the index value of the parser maps
is always a unsigned value.

mysql-test/r/ctype_recoding.result:
  Update test case result: ending backtick is not skipped over anymore.
sql/sql_lex.cc:
  Characters being analyzed must be unsigned as they can be
  used as indexes for the parser maps. Only skip over if the
  string is a valid multi-byte sequence.
tests/mysql_client_test.c:
  Add test case for Bug#45010

- When collecting Item_subselect::refers_to, put references to the correct
  subselect entry.

> ------------------------------------------------------------
> revno: 2852.2.3
> revision-id: davi.arnaut@sun.com-20090403194600-60ufn0tz1gx1kl0l
> parent: gni@mysql.com-20090403184200-vnjtpsv4an79w8bu
> parent: davi.arnaut@sun.com-20090403191154-0ho2nai3chjsmpof
> committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
> branch nick: 43230-5.1
> timestamp: Fri 2009-04-03 16:46:00 -0300
> message:
>   Merge Bug#43230 into mysql-5.1-bugteam
>     ------------------------------------------------------------
>     revno: 1810.3855.16
>     revision-id: davi.arnaut@sun.com-20090403191154-0ho2nai3chjsmpof
>     parent: chad@mysql.com-20090402152928-3ld60a56h86njcpg
>     committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
>     branch nick: 43230-5.0
>     timestamp: Fri 2009-04-03 16:11:54 -0300
>     message:
>       Bug#43230: SELECT ... FOR UPDATE can hang with FLUSH TABLES WITH READ LOCK indefinitely
>       
>       The problem is that a SELECT .. FOR UPDATE statement might open
>       a table and later wait for a impeding global read lock without
>       noticing whether it is holding a table that is being waited upon
>       the the flush phase of the process that took the global read
>       lock.
>       
>       The same problem also affected the following statements:
>       
>       LOCK TABLES .. WRITE
>       UPDATE .. SET (update and multi-table update)
>       TRUNCATE TABLE ..
>       LOAD DATA ..
>       
>       The solution is to make the above statements wait for a impending
>       global read lock before opening the tables. If there is no
>       impending global read lock, the statement raises a temporary
>       protection against global read locks and progresses smoothly
>       towards completion.
>       
>       Important notice: the patch does not try to address all possible
>       cases, only those which are common and can be fixed unintrusively
>       enough for 5.0.

- Make elimination check to be able detect cases like  t.primary_key_col1=othertbl.col AND t.primary_key_col2=func(t.primary_key_col1).
  These are needed to handle e.g. the case of func() being a correlated subquery that selects the latest value.
- If we've removed a condition with subquery predicate, EXPLAIN [EXTENDED] won't show the subquery anymore

sql/item.cc:
  MWL#17: Table elimination
  - Add tem_field::check_column_usage_processor(). it allows to check which key parts a condition depends on.
sql/item.h:
  MWL#17: Table elimination
  - Add tem_field::check_column_usage_processor(). it allows to check which key parts a condition depends on.
sql/item_subselect.cc:
  MWL#17: Table elimination
  - Item_subselect got 'eliminated' attribute. It is used only to determine if the subselect should be printed by EXPLAIN.
  - Item_subselect got List<Item> refers_to - a list of item in the current select that are referred to from within the subselect.
  - Added Item_*::check_column_usage_processor(). it allows to check which key parts a condition depends on.
  - Added a comment about possible problem in Item_subselect::walk
sql/item_subselect.h:
  MWL#17: Table elimination
  - Item_subselect got 'eliminated' attribute. It is used only to determine if the subselect should be printed by EXPLAIN.
  - Item_subselect got List<Item> refers_to - a list of item in the current select that are referred to from within the subselect.
  - Added Item_*::check_column_usage_processor(). it allows to check which key parts a condition depends on.
sql/item_sum.cc:
  MWL#17: Table elimination
sql/sql_lex.cc:
  MWL#17: Table elimination
sql/sql_lex.h:
  MWL#17: Table elimination
sql/sql_select.h:
  MWL#17: Table elimination

with gcc 4.3.2
      
Compiling MySQL with gcc 4.3.2 and later produces a number of 
warnings, many of which are new with the recent compiler
versions.
                  
This bug will be resolved in more than one patch to limit the
size of changesets. This is the second patch, fixing more
of the warnings.

with gcc 4.3.2

Compiling MySQL with gcc 4.3.2 and later produces a number of 
warnings, many of which are new with the recent compiler
versions.
            
This bug will be resolved in more than one patch to limit the
size of changesets. This is the second patch, fixing more
of the warnings.

      
Added a more detailed error message on calling an ambiguous missing function.

mysql-test/r/ps.result:
  Bug #38159: fixed existing tests
mysql-test/r/sp-error.result:
  Bug #38159: test case
mysql-test/t/ps.test:
  Bug #38159: fixed existing tests
mysql-test/t/sp-error.test:
  Bug #38159: test case
sql/item_func.cc:
  Bug #38159: generate more detailed error message
sql/share/errmsg.txt:
  Bug #38159: add a more detailed error message
sql/sql_derived.cc:
  Bug #38159: treat the detailed error message the same way as the
  generic one
sql/sql_lex.cc:
  Bug #38159: 
    - detect if the token is ambiguous and print the appropriate error.
    - backport is_lex_native_function() from 5.1
sql/sql_lex.h:
  Bug #38159: detect if the token is ambiguous and print the appropriate error.
sql/sql_yacc.yy:
  Bug #38159: generate more detailed error message
sql/table.cc:
  Bug #38159: treat the detailed error message the same way as the
  generic one

	comment can't be read back

A change to the lexer in 5.1 caused slash-asterisk-bang-version
sections to be terminated early if there exists a slash-asterisk-
style comment inside it.  Nesting comments is usually illegal,
but we rely on versioned comment blocks in mysqldump, and the
contents of those sections must be allowed to have comments.

The problem was that when encountering open-comment tokens and
consuming -or- passing through the contents, the "in_comment"
state at the end was clobbered with the not-in-a-comment value,
regardless of whether we were in a comment before this or not.  

So, """/*!VER one /* two */ three */""" would lose its in-comment
state between "two" and "three".  Save the echo and in-comment
state, and restore it at the end of the comment if we consume a 
comment.

The problem is that a SELECT .. FOR UPDATE statement might open
a table and later wait for a impeding global read lock without
noticing whether it is holding a table that is being waited upon
the the flush phase of the process that took the global read
lock.

The same problem also affected the following statements:

LOCK TABLES .. WRITE
UPDATE .. SET (update and multi-table update)
TRUNCATE TABLE ..
LOAD DATA ..

The solution is to make the above statements wait for a impending
global read lock before opening the tables. If there is no
impending global read lock, the statement raises a temporary
protection against global read locks and progresses smoothly
towards completion.

Important notice: the patch does not try to address all possible
cases, only those which are common and can be fixed unintrusively
enough for 5.0.

mysql-test/r/lock_multi.result:
  Add test case result for Bug#43230
mysql-test/t/lock_multi.test:
  Add test case for Bug#43230
sql/sql_lex.cc:
  Initialize flag.
sql/sql_lex.h:
  Add a flag to the lexer.
sql/sql_parse.cc:
  Wait for the global read lock is a write lock is going to be
  taken. The wait is done before opening tables.
sql/sql_yacc.yy:
  Protect against the GRL if its a SELECT .. FOR UPDATE or LOCK TABLES
  .. WRITE statement.

An unnecessarily restrictive lock were taken on sub-SELECTs during DELETE.

During parsing, a global structure is reused for sub-SELECTs and the attribute
keeping track of lock options were not reset properly.
This patch introduces a new attribute to keep track on the syntactical lock
option elements found in a sub-SELECT and then sets the lock options accordingly.

Now the sub-SELECTs will try to acquire a READ lock if possible
instead of a WRITE lock as inherited from the outer DELETE statement.


mysql-test/r/lock.result:
  Added test case for bug39843
mysql-test/t/lock.test:
  Added test case for bug39843
sql/sql_lex.cc:
  * Reset member variable lock_option on each new query.
sql/sql_lex.h:
  * Introduced new member variable 'lock_option' which is keeping track
    of the syntactical lock option of a (sub-)select query.
sql/sql_parse.cc:
  * Wrote comments to functions.
sql/sql_yacc.yy:
  * Introduced an attribute to keep track of syntactical lock options
    in sub-selects.
  * Made sure that the default value TL_READ_DEFAULT is at the begining
    of each subselect-rule.

- Remove bothersome warning messages.  This change focuses on the warnings 
that are covered by the ignore file: support-files/compiler_warnings.supp.
- Strings are guaranteed to be max uint in length

- Added braces around expressions with &&, ||, & and |
- Added empty line before ; for empty while and for loops
- Added () around if with assignments
- Removed const before function returning simple type

Changed BUILD scripts to not build with NDB 


BUILD/SETUP.sh:
  By default, don't build ndb with --max in Maria tree.
  NDB is not kept up to date anyway in 5.1
client/mysql.cc:
  Added braces around && to get rid of compiler warnings
sql/event_db_repository.cc:
  Added braces around && to get rid of compiler warnings
sql/events.cc:
  Added braces around && to get rid of compiler warnings
sql/field.cc:
  Added braces around && to get rid of compiler warnings
  Fixed for loops
sql/field.h:
  Added braces around & to get rid of compiler warnings
sql/field_conv.cc:
  Added braces around && to get rid of compiler warnings
  Fixed bug when copying between DATETIME fields and strict dates are used
  Removed not needeed else
sql/gstream.cc:
  Added braces around && to get rid of compiler warnings
sql/ha_ndbcluster.cc:
  Added braces around && to get rid of compiler warnings
  Added {} to get rid of compiler warnings
sql/handler.cc:
  Added braces around && to get rid of compiler warnings
sql/item.cc:
  Added braces around && to get rid of compiler warnings
sql/item_cmpfunc.cc:
  Added braces around && to get rid of compiler warnings
  Removed some not needed space
sql/item_func.cc:
  Added braces around && to get rid of compiler warnings
sql/item_strfunc.cc:
  Added braces around && to get rid of compiler warnings
sql/item_subselect.cc:
  Added braces around && to get rid of compiler warnings
sql/item_sum.cc:
  Added braces around && to get rid of compiler warnings
sql/item_timefunc.cc:
  Added braces around && to get rid of compiler warnings
sql/item_xmlfunc.cc:
  Added empty line before ; for empty while and for loops
sql/log.cc:
  Added braces around && to get rid of compiler warnings
sql/log_event.cc:
  Added braces around && to get rid of compiler warnings
  Removed not needed else
sql/log_event_old.cc:
  Added braces around && to get rid of compiler warnings
sql/opt_range.cc:
  Added braces around && to get rid of compiler warnings
sql/opt_sum.cc:
  Added braces around && to get rid of compiler warnings
sql/set_var.cc:
  Added empty line before ; for empty while and for loops
  Added () around if with assignments
sql/slave.cc:
  Added braces around && to get rid of compiler warnings
  Added empty line before ; for empty while and for loops
sql/spatial.h:
  Added braces around && to get rid of compiler warnings
sql/sql_acl.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_analyse.cc:
  Added empty line before ; for empty while and for loops
sql/sql_base.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_connect.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_db.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_delete.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_help.cc:
  Added empty line before ; for empty while and for loops
sql/sql_insert.cc:
  Added braces around && to get rid of compiler warnings
  Added () around if with assignments
sql/sql_lex.cc:
  Cast char array references to uchar; Fixed wrong array referencing when using characters > ASCII 128 in SQL statments
  Added empty line before ; for empty while and for loops
  Trivial indent fixes
  Added braces around && to get rid of compiler warnings
sql/sql_load.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_parse.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_partition.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_plugin.cc:
  Fixed bug in detecing if option variable should be readonly
  Added empty line before ; for empty while and for loops
sql/sql_prepare.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_select.cc:
  Added braces around && to get rid of compiler warnings
  Added () around if with assignments
  Added empty line before ; for empty while and for loops
sql/sql_show.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_table.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_trigger.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_update.cc:
  Added braces around && to get rid of compiler warnings
sql/sql_yacc.yy:
  Added braces around && to get rid of compiler warnings
sql/table.cc:
  Added braces around && to get rid of compiler warnings
sql/table.h:
  Added braces around && to get rid of compiler warnings
sql/time.cc:
  Added braces around && to get rid of compiler warnings
sql/tztime.cc:
  Added braces around && to get rid of compiler warnings
sql/uniques.cc:
  Added braces around && to get rid of compiler warnings
storage/federated/ha_federated.cc:
  Fixed bug in testing of variable to ha_info() (Not critical)
storage/heap/ha_heap.cc:
  Added braces around && to get rid of compiler warnings
storage/maria/ha_maria.cc:
  Fixed bug: Mark that maria_log_dir_path is readonly
  Added braces around && to get rid of compiler warnings
storage/ndb/include/ndbapi/NdbEventOperation.hpp:
  Removed const before function returning simple type
storage/ndb/include/ndbapi/NdbOperation.hpp:
  Removed const before function returning simple type
storage/ndb/src/ndbapi/Ndb.cpp:
  Added empty line before ; for empty while and for loops
storage/ndb/src/ndbapi/NdbEventOperation.cpp:
  Removed const before function returning simple type
storage/ndb/src/ndbapi/NdbEventOperationImpl.cpp:
  Removed const before function returning simple type
storage/ndb/src/ndbapi/NdbEventOperationImpl.hpp:
  Removed const before function returning simple type
storage/ndb/src/ndbapi/NdbRecAttr.cpp:
  Added empty line before ; for empty while and for loops
storage/ndb/src/ndbapi/TransporterFacade.hpp:
  Added braces around && to get rid of compiler warnings

Related to operator precedence and associativity.
Make the expressions as explicit as possible.

sql/field.h:
  Silence gcc-4.3 warning: be more explicit.
sql/item.cc:
  Silence gcc-4.3 warning: be more explicit.
sql/item_sum.cc:
  Silence gcc-4.3 warning: be more explicit.
sql/log_event.cc:
  Silence gcc-4.3 warning: be more explicit.
sql/spatial.h:
  Silence gcc-4.3 warning: be more explicit.
sql/sql_lex.cc:
  Silence gcc-4.3 warning: be more explicit.
sql/table.h:
  Silence gcc-4.3 warning: be more explicit.
storage/federated/ha_federated.cc:
  Fix operator precedence bug.
storage/heap/ha_heap.cc:
  Silence gcc-4.3 warning: be more explicit.

since Oct 1st

The problem is that the offset argument of the limit clause
might be truncated on a 32-bits server built without big
tables support. The truncation was happening because the
original 64-bits long argument was being cast to a 32-bits
(ha_rows) offset counter.

The solution is to check if the conversing resulted in value
truncation and if so, the offset is set to the maximum possible
value that can fit on the type.

mysql-test/r/limit.result:
  Add test case result for Bug#37075
mysql-test/t/limit.test:
  Add test case for Bug#37075
sql/sql_lex.cc:
  Check for truncation of the offset value. If value was
  truncated, set to the maximum possible value.

          ``FLUSH TABLES WITH READ LOCK''

Concurrent execution of 1) multitable update with a
NATURAL/USING join and 2) a such query as "FLUSH TABLES
WITH READ LOCK" or "ALTER TABLE" of updating table led
to a server crash.


The mysql_multi_update_prepare() function call is optimized
to lock updating tables only, so it postpones locking to
the last, and if locking fails, it does cleanup of modified
syntax structures and repeats a query analysis.  However,
that cleanup procedure was incomplete for NATURAL/USING join
syntax data: 1) some Field_item items pointed into freed
table structures, and 2) the TABLE_LIST::join_columns fields
was not reset.

Major change:
  short-living Field *Natural_join_column::table_field has
  been replaced with long-living Item*.


mysql-test/r/lock_multi.result:
  Added test case for bug #38691.
mysql-test/t/lock_multi.test:
  Added test case for bug #38691.
sql/item.cc:
  Bug #38691: segfault/abort in ``UPDATE ...JOIN'' while
            ``FLUSH TABLES WITH READ LOCK''
  
  The Item_field constructor has been modified to allocate
  and copy original database/table/field names always (not
  during PS preparation/1st execution only), because
  an initialization of Item_field items with a pointer to
  short-living Field structures is a common practice.
sql/sql_base.cc:
  Bug #38691: segfault/abort in ``UPDATE ...JOIN'' while
            ``FLUSH TABLES WITH READ LOCK''
  
  1) Type adjustment for Natural_join_column::table_field
     (Field to Item_field);
  2) The setup_natural_join_row_types function has been
     updated to take into account new
     first_natural_join_processing flag to skip unnecessary
     reinitialization of Natural_join_column::join_columns
     during table reopening after lock_tables() failure
     (like the 'first_execution' flag for PS).
sql/sql_lex.cc:
  Bug #38691: segfault/abort in ``UPDATE ...JOIN'' while
            ``FLUSH TABLES WITH READ LOCK''
  
  Initialization of the new
  st_select_lex::first_natural_join_processing flag has
  been added.
sql/sql_lex.h:
  Bug #38691: segfault/abort in ``UPDATE ...JOIN'' while
            ``FLUSH TABLES WITH READ LOCK''
  
  The st_select_lex::first_natural_join_processing flag
  has been added to skip unnecessary rebuilding of
  NATURAL/USING JOIN structures during table reopening
  after lock_tables failure.
sql/sql_update.cc:
  Bug #38691: segfault/abort in ``UPDATE ...JOIN'' while
            ``FLUSH TABLES WITH READ LOCK''
  
  Extra cleanup calls have been added to reset
  Natural_join_column::table_field items.
sql/table.cc:
  Bug #38691: segfault/abort in ``UPDATE ...JOIN'' while
            ``FLUSH TABLES WITH READ LOCK''
  
  Type adjustment for Natural_join_column::table_field
  (Field to Item_field).
sql/table.h:
  Bug #38691: segfault/abort in ``UPDATE ...JOIN'' while
            ``FLUSH TABLES WITH READ LOCK''
  
  Type of the Natural_join_column::table_field field has
  been changed from Field that points into short-living
  TABLE memory to long-living Item_field that can be
  linked to (fixed) reopened table.