1. Changed the lazy optimization for subqueries that can be
   materialized into bottom-up optimization during the optimization of
   the main query.

   The main change is implemented by the method
   Item_in_subselect::setup_engine.
  
   All other changes were required to correct problems resulting from
   changing the order of optimization. Most of these problems followed
   the same pattern - there are some shared structures between a
   subquery and its parent query. Depending on which one is optimized
   first (parent or child query), these shared strucutres may get
   different values, thus resulting in an inconsistent query plan.

2. Changed the code-generation for subquery materialization to be
   performed in runtime memory for each (re)execution, instead of in
   statement memory (once per prepared statement).
   - Item_in_subselect::setup_engine() no longer creates materialization
     related objects in statement memory.
   - Merged subselect_hash_sj_engine::init_permanent and
     subselect_hash_sj_engine::init_runtime into
     subselect_hash_sj_engine::init, which is called for each
     (re)execution.
   - Fixed deletion of the temp table accordingly.


mysql-test/r/subselect_mat.result:
  Adjusted changed EXPLAIN because of earlier optimization of subqueries.

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.

- Item_in_subselect::init_left_expr_cache() should not try to 
  guess whether the left expression is accessed "over the grouping operation"
  (i.e. the subselect is evaluated after the grouping while the left_expr is
   an Item_ref that wraps an expression from before the grouping). Instead, 
  let new_Cached_item not to try accessing item->real_item() when creating 
  left expr cache.

join cache module.
Without these calls SELECTs over tables with virtual columns
that used join cache could return wrong results. This could
be seen with the test case added into vcol_misc.test 

  field->pack_length() bytes.

5.3 had 

 handler::index_only_read_time(uint keynr, double records)

while 5.2 got:

 handler::keyread_read_time(uint index, uint ranges, ha_rows rows)

which causes floor()'ing of rows parameter, which makes all further costs different.

- fix a bug in LooseScan strategy execution code (exposed by changing costs/QEP)
- Do set join_tab->sorted=TRUE for JOIN_TABs that use LooseScan (partitioning 
   handler cares about "sorted" parameter of h->index_init() call)

create st_maria_plugin declarations of new xtradb I_S tables

* remove handler::index_read_last()
* create handler::keyread_read_time() (was get_index_only_read_time() in opt_range.cc)
* ha_show_status() allows engine's show_status() to fail
* remove HTON_FLUSH_AFTER_RENAME
* fix key_cmp_if_same() to work for floats and doubles
* set table->status in the server, don't force engines to do it
* increment status vars in the server, don't force engines to do it

mysql-test/r/status_user.result:
  correct test results - innodb was wrongly counting internal
  index searches as handler_read_* calls.
sql/ha_partition.cc:
  compensate for handler incrementing status counters -
  we want to count only calls to underlying engines
sql/handler.h:
  inline methods moved to sql_class.h
sql/key.cc:
  simplify the check
sql/opt_range.cc:
  move get_index_only_read_time to the handler class
sql/sp.cc:
  don't use a key that's stored in the record buffer -
  the engine can overwrite the buffer with anything, destroying the key
sql/sql_class.h:
  inline handler methods that need to see THD and TABLE definitions
sql/sql_select.cc:
  no ha_index_read_last_map anymore
sql/sql_table.cc:
  remove HTON_FLUSH_AFTER_RENAME
sql/table.cc:
  set HA_CAN_MEMCMP as appropriate
sql/tztime.cc:
  don't use a key that's stored in the record buffer -
  the engine can overwrite the buffer with anything, destroying the key
storage/myisam/ha_myisam.cc:
  engines don't need to update table->status or use ha_statistic_increment anymore
storage/myisam/ha_myisam.h:
  index_read_last_map is no more

mysql-test/suite/pbxt/r/mysqlshow.result:
  update the forgotten test results
sql/table.cc:
  add defensive asserts.
  fix the code that didn't in MySQL > 5.2.0 with frm's created before 5.1.10

Fixed failing test innodb.innodb-autoinc.test
Enabled innodb test suite

mysql-test/mysql-test-run.pl:
  Enabled innodb test suite
mysql-test/r/innodb-autoinc.result:
  Removed test as it exists in suite innodb
mysql-test/suite/innodb/t/disabled.def:
  Removed innodb-autoinc
mysql-test/suite/innodb/t/innodb-autoinc.test:
  Update to be able to run with plugin
mysql-test/t/innodb-autoinc.test:
  Removed test as it exists in suite innodb
sql/filesort.cc:
  Removed not used variable
sql/slave.cc:
  Remove compiler warnings
storage/pbxt/src/ha_pbxt.cc:
  Removed not used variable
storage/xtradb/dict/dict0crea.c:
  Fixed compiler warning about unsigned comparison
support-files/compiler_warnings.supp:
  Disable some not relevant warnings

include/Makefile.am:
  Make my_valgrind.h global (as it's used by my_global.h)
include/my_global.h:
  Include my_valgrind.h
include/my_sys.h:
  TRASH() moved to my_valgrind.h
include/my_valgrind.h:
  Add VALGRIND defines to mark memory
mysys/my_alloc.c:
  Mark internal freed memory as undefined

storage/pbxt/src/ha_pbxt.cc:
  LOCK_plugin is not locked anymore as part of plugin initialization

Fixed some bugs introduced in 5.1.47
Disabled some tests until we have merged with latest Xtradb

configure.in:
  Added testing if valgrind/memcheck.h exists
storage/pbxt/src/ha_pbxt.cc:
  LOCK_plugin is not anymore locked in init

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.

Fix a couple of problems in the pack script, and disable a check feature that doesn't work right now

and the server suddenly goes away

The statistics after a sequence of inserts/deletes are updated asynchronously
in PBXT, causing unpredictable test results. Fix by running the test on a
fresh copy of the table with no deletes performed, to get stable results.

1. fix broken change user handling (no restart should happen in the normal case)
2. add assert to guarantee that we never send a request to change to the same plugin
3. "fix" plugin string as sent by the client to be able to compare native plugins by pointers
4. more complete MYSQL initialization in the embedded case
5. change_user.test updated to handle -with-embedded-privilege-control builds