in the function best_access_path revealed another bug: currently 
table scans on NULL keys used for NOT IN subqueries cannot work 
together with employment of join caches for inner tables of these 
subqueries. Otherwise the result can be wrong as it could be seen 
with the result of the test case constructed for bug #37894 
in the file subselect3_jcl6.result.

of the 5.3 code line after a merge with 5.2 on 2010-10-28
in order not to allow the cost to access a joined table to be equal
to 0 ever.

Expanded data sets for many test cases to get the same execution plans
as before.

- The problem was that Item_direct_view_ref and its embedded Item_field were getting incorrect
  value of item->used_tables() after fix_fields() in the second and subsequent EXECUTE.
- Made relevant fixes in Item_field::fix_fields() and find_field_in_tables(), so that the 
  Item_field gets the correct attributes.

BUG##849717: Crash in Item_func::fix_fields on second execution of a prepared statement with semijoin
- If convert_join_subqueries_to_semijoins() decides to wrap Item_in_subselect in Item_in_optimizer, 
  it should do so in prep_on_expr/prep_where, too, as long as they are present.
  There seems to be two possibilities of how we arrive in this function:
  - prep_on_expr/prep_where==NULL, and will be set later by simplify_joins()
  - prep_on_expr/prep_where!=NULL, and it is a copy_and_or_structure()-made copy of on_expr/where.
  the latter can happen for some (but not all!) nested joins. This bug was that we didn't handle this case.

(Code taken from 5.5)

- Mrr_ordered_index_reader::interrupt_read() and resume_read() should 
  save/restore not just index lookup tuple, but entire index tuple.
  Key parts that are not used for index lookup can be still used in
  pushed index condition. Failure to save/restore will cause the index
  condition to be evaluated over the wrong values.

Give proper error to client on shutdown.

configure.in:
  Increased version number
mysql-test/mysql-test-run.pl:
  Ignore errors that one can get while running with --mysqld=--log-warnings=2
mysql-test/r/variables.result:
  Remember original value of log_warnings
mysql-test/suite/rpl/r/rpl_idempotency.result:
  Ignore errors that one can get while running with --mysqld=--log-warnings=2
mysql-test/suite/rpl/t/rpl_idempotency.test:
  Ignore errors that one can get while running with --mysqld=--log-warnings=2
mysql-test/t/variables.test:
  Remember original value of log_warnings
sql/mysqld.cc:
  Give proper error to close_connection() on shutdown
storage/maria/ha_maria.cc:
  Added missing DBUG_RETURN

Fixed that automatic killing of delayed insert thread (in flush, alter table etc) will not abort auto-repair of MyISAM table.
Give more information when finding an error in a MyISAM table.
When killing system thread, use KILL_SYSTEM_THREAD instead of KILL_CONNECTION to make it easier to ignore the signal in sensitive context (like auto-repair)
Added new kill level: KILL_SERVER that will in the future to be used to signal killed by shutdown.
Add more warnings about killed connections when warning level > 3

include/myisamchk.h:
  Added counting of printed info/notes
mysys/mf_iocache.c:
  Remove duplicate assignment
sql/handler.cc:
  Added test of KILL_SERVER
sql/log.cc:
  Ignore new 'kill' error ER_NEW_ABORTING_CONNECTION when requesting query error code.
sql/mysqld.cc:
  Add more warnings for killed connections when warning level > 3
sql/scheduler.cc:
  Added checks for new kill signals
sql/slave.cc:
  Ignore new kill signal ER_NEW_ABORTING_CONNECTION
sql/sp_head.cc:
  Fixed assignment to bool
  Added testing of new kill signals
sql/sql_base.cc:
  Use KILL_SYSTEM_THREAD to auto-kill system threads
sql/sql_class.cc:
  Add more warnings for killed connections when warning level > 3
  thd_killed() now ignores KILL_BAD_DATA and THD::KILL_SYSTEM_THREAD as these should not abort sensitive operations.
sql/sql_class.h:
  Added KILL_SYSTEM_THREAD and KILL_SERVER
sql/sql_connect.cc:
  Added handling of KILL_SERVER
sql/sql_insert.cc:
  Use KILL_SYSTEM_THREAD to auto-kill system threads
  Added handling of KILL_SERVER
sql/sql_parse.cc:
  Add more warnings for killed connections when warning level > 3
  Added checking that thd->abort_on_warning is reset at end of query.
sql/sql_show.cc:
  Update condition for when a query is 'killed'
storage/myisam/ha_myisam.cc:
  Added counting of info/notes printed
storage/myisam/mi_check.c:
  Always print an an error if we find data errors when checking/repairing a MyISAM table.
  When a repair was killed, don't retry repair.
  Added assert if sort_get_next_record() returned an error without an error message.
  Removed nonsence check "if (sort_param->read_cache.error < 0)" in repair.
storage/myisam/myisamchk.c:
  Added counting of notes printed
storage/pbxt/src/thread_xt.cc:
  Better error message.

- The bug was caused by outer join being incorrectly converted into inner because of 
  invalid return values of Item_direct_view_ref::not_null_tables().
- Provided a correct Item_direct_view_ref::not_null_tables() function.

- Let join buffering code correctly take into account rowids needed 
  by DuplicateElimination when it is calculating minimum record sizes.
- In JOIN_CACHE::write_record_data, added asserts that prevent us from 
  writing beyond the end of the buffer.

The problem was that optimization code did not take into account later feature when instad of NOT before BETWEEN it has negated flag into the Item_func_between inherited from Item_func_neg_opt. So optimizer tried process NOT BETWEEN as BETWEEN.

The patch just switches off the optimisation for NOT BETWEEN as it was before when NOT function was really used.

remove incorrect DBUG_ASSERT().
Fix incorrectly used cmp_item::get_comparator() in Item_func_case and Item_equal

For any query JOIN::optimize() should call the method
SELECT::save_leaf_tables after the last transformation
that utilizes the statement memory rather than the 
execution memory.
  

- Make subquery_types_allow_materialization() detect a case where 
  create_tmp_table() would create a blob column which would make it 
  impossible to use materialization
  Non-semi-join materialization worked because it detected that this case
  and felt back to use IN->EXISTS. Semi-join Materialization cannot easily
  fallback, so we have to detect this case early.

- Don't use join buffering for tables that are within ranges that are 
  covered by LooseScan strategy.

- get_bound_sj_equalities() would produce incorrect bitmap when non-first 
  equality was bound, which resulted in invalid LooseScan plans.

  
  ALL subquery should return TRUE if subquery rowa set is empty independently
  of left part.  The problem was that Item_func_(eq,ne,gt,ge,lt,le) do not
  call execution of second argument if first is NULL no in this case subquery
  will not be executed and when Item_func_not_all calls any_value() of the
  subquery or aggregation function which report that there was rows. So for
  NULL < ALL (SELECT...) result was FALSE instead of TRUE.
  
  Fix is just swapping of arguments of Item_func_(eq,ne,gt,ge,lt,le) (with
  changing the operation if it is needed) so that result will be the same
  (for examole a < b is equal to b > a). This fix exploit the fact that
  first argument will be executed in any case.

- Item_in_subselect::inject_in_to_exists_cond() should not call 
  ((Item_cond*)join->conds)->argument_list()->concat(join->cond_equal->current_level)
  as that makes two lists share their tail, and the cond_equal list
  will end up containing non-Item_equal objects when substitute_for_best_equal_field()
  walks through join->conds and replaces all Item_equal objects with Item_func_eq objects.
  - So, instead of using List::concat(), manually copy entries from one list to another.
 

- Make find_all_keys() not to rely on table->tmp_set remaining constant during execution
  quick_index_merge_select->reset() may change it.