- Let DS-MRR/CPK take advantage of materialized keys, when possible

- Lots of TODO comments
- add mrr_sort_keys flag to @@optimizer_switch
- [from Igor] SQL layer part passes HA_MRR_MATERIALIZED_KEYS flag
- Don't call rnd_pos() many times in a row if sorted rowid buffer
  has the same rowid value for multiple consequive (rowid, range_id) pairs.

- Merge with current 5.3

- Let "mysqld  --help --verbose" list all optimizer options
- Make it possible to add new @@optimizer_switch flags w/o causing .result 
  changes all over the testsuite:
  = Remove "select @@optimizer_switch" from tests that do not need all switches
  = Move @@optimizer_switch-specific tests to t/optimizer_switch.test

Updated configure.in to have version 5.3

configure.in:
  Updated to version 5.3.0

Improved speed of thr_alarm from O(N) to O(1). thr_alarm is used to handle timeouts and kill of connections.
Fixed compiler warnings.
queues.h and queues.c are now based on the UNIREG code and thus made BSD.
Fix code to use new queue() interface. This mostly affects how you access elements in the queue.
If USE_NET_CLEAR is not set, don't clear connection from unexpected characters. This should give a speed up when doing a lot of fast queries.
Fixed some code in ma_ft_boolean_search.c that had not made it from myisam/ft_boolean_search.c


include/queues.h:
  Use UNIREG code base (BSD)
  Changed init_queue() to take all initialization arguments.
  New interface to access elements in queue
include/thr_alarm.h:
  Changed to use time_t instead of ulong (portability)
  Added index_in_queue, to be able to remove random element from queue in O(1)
mysys/queues.c:
  Use UNIREG code base (BSD)
  init_queue() and reinit_queue() now takes more initialization arguments. (No need for init_queue_ex() anymore)
  Now one can tell queue_insert() to store in the element a pointer to where element is in queue. This allows one to remove elements from queue in O(1) instead of O(N)
mysys/thr_alarm.c:
  Use new option in queue() to allow fast removal of elements.
  Do less inside LOCK_alarm mutex.
  This should give a major speed up of thr_alarm usage when there is many threads
sql/create_options.cc:
  Fixed wrong printf
sql/event_queue.cc:
  Use new queue interface()
sql/filesort.cc:
  Use new queue interface()
sql/ha_partition.cc:
  Use new queue interface()
sql/ha_partition.h:
  Fixed compiler warning
sql/item_cmpfunc.cc:
  Fixed compiler warning
sql/item_subselect.cc:
  Use new queue interface()
  Removed not used variable
sql/net_serv.cc:
  If USE_NET_CLEAR is not set, don't clear connection from unexpected characters.
  This should give a speed up when doing a lot of fast queries at the disadvantage that if there is a bug in the client protocol the connection will be dropped instead of being unnoticed.
sql/opt_range.cc:
  Use new queue interface()
  Fixed compiler warnings
sql/uniques.cc:
  Use new queue interface()
storage/maria/ma_ft_boolean_search.c:
  Copy code from myisam/ft_boolean_search.c
  Use new queue interface()
storage/maria/ma_ft_nlq_search.c:
  Use new queue interface()
storage/maria/ma_sort.c:
  Use new queue interface()
storage/maria/maria_pack.c:
  Use new queue interface()
  Use queue_fix() instead of own loop to fix queue.
storage/myisam/ft_boolean_search.c:
  Use new queue interface()
storage/myisam/ft_nlq_search.c:
  Use new queue interface()
storage/myisam/mi_test_all.sh:
  Remove temporary file from last run
storage/myisam/myisampack.c:
  Use new queue interface()
  Use queue_fix() instead of own loop to fix queue.
storage/myisam/sort.c:
  Use new queue interface()
storage/myisammrg/myrg_queue.c:
  Use new queue interface()
storage/myisammrg/myrg_rnext.c:
  Use new queue interface()
storage/myisammrg/myrg_rnext_same.c:
  Use new queue interface()
storage/myisammrg/myrg_rprev.c:
  Use new queue interface()

range plans with identical costs.

subquery execution, where the the REF buffer format was mistaken to
be in record format instead of key format. The error was that the null
byte for all fields of the record was in the front of the buffer,
and not before each field data.

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)

- Remove back key_parts from multi_range_read_init() parameters
- Related code simplification/cleanup

- Fix the code to work with IndexConditionPushdown+BKA (EXPLAIN is still 
  incorrect, see comments in the patch)
- Test coverage for ICP+BKA

- Add testcases
- Code cleanup: garbage removal, better comments, make members private where possible

- Add testcases

- First code (will need code cleanup)

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