- Changed Cached_item_field not copy data for fields with NULL value
- In key_copy() and key_restore() don't copy data for fields with NULL value

Fixed code to avoid valgrind warnings
- Use c_ptr_safe instead of c_ptr()

Removed "QQ" from comments (QQ was ment to be used for internal comments that should be removed before pushing)
Fixed wrong alias used (from previous patch)


sql/event_db_repository.cc:
  Update testing if event table is valid (to avoid valgrind errors)
sql/ha_partition.cc:
  m_ordered_scan_ongoing was not initialized
  Reset null bits in record to avoid valgrind errors
sql/handler.h:
  Added flag if storage engine will write row verbatim and the row contains varchar or null fields
  (in which case we must clear the row to avoid valgrind warnings)
sql/item_buff.cc:
  Changed Cached_item_field not copy data for fields with NULL value
  (Optimization and avoids valgrind warnings)
sql/item_func.cc:
  c_ptr() -> c_ptr_safe()
sql/key.cc:
  In key_copy() and key_restore() don't copy data for fields with NULL value
sql/opt_range.cc:
  c_ptr() -> c_ptr_safe()
sql/sql_base.cc:
  Added TRASH() to table->record[0] to find out if we access not initialzed data.
  Initialize null_bytes to:
  - Get consistent tests
  - Ensure we don't get valgrind warnings for null fields (as we may only update a couple of bits in a byte)
sql/sql_class.cc:
  Removed "QQ" from comments
sql/sql_insert.cc:
  Initialize row to default values if we are using valgrind and row will be copied verbatim to disk in storage engine.
sql/sql_load.cc:
  QQ -> TODO
sql/sql_parse.cc:
  Removed old not used code marked QQ and withing "#ifdef REMOVED"
sql/sql_select.cc:
  QQ -> TODO
  Initialize some variables that was used uninitialized
  Added DBUG_ASSERT() to find out if thd was not properly initialized for sub queries
sql/sql_test.cc:
  Fixed format for printing to DBUG file
  Fixed wrong alias used (from previous patch)
sql/sql_trigger.h:
  QQ -> TODO
sql/table.cc:
  QQ -> TODO
storage/maria/ha_maria.cc:
  Mark table with HA_RECORD_MUST_BE_CLEAN_ON_WRITE, if row is written verbatim to disk and contains varchar or null fields.
storage/maria/ma_open.c:
  Added flags if table has varchar or null fields
storage/maria/maria_def.h:
  Added flags if table has varchar or null fields
storage/myisam/ha_myisam.cc:
  Mark table with HA_RECORD_MUST_BE_CLEAN_ON_WRITE, if row is written verbatim to disk and contains varchar or null fields.
storage/myisam/mi_open.c:
  Fixed memory overrun bug when using fulltext keys
storage/xtradb/row/row0sel.c:
  Removed initialization of null bits. (not needed anymore)

Fix MySQL BUG#52344 - Subquery materialization: Assertion if subquery in on-clause of outer join

Original fix and comments from Oysten, adjusted for the different
subquery optimization in MariaDB.
"
Problem: If tables of an outer join are constant tables,
the associated on-clause will be evaluated in the optimization
phase. If the on-clause contains a query that is to be
executed with subquery materialization, this will not work
since the infrastructure for such execution is not yet set up.
      
Solution: Do not evaluate on-clause in optimization phase if
is_expensive() returns true for this clause.  This is how the
problem is currently avoided for where-clauses.  This works
because, Item_in_subselect::is_expensive_processor returns true
if query is to be executed with subquery materialization.
"
In addition, after MWL#89, in MariaDB if the IN-EXISTS strategy
is chosen, the in-to-exists predicates are insterted after
join_read_const_table() is called, resulting in evaluation of
the subquery without the in-to-exists predicates.

  
Analysis:
The send_data method of the result sink class used to collect
data statistics about materialized subqueries incorrectly assumed
that duplicate rows are removed prior to calling send_data. As
a result the collected statistics was wrong, which resulted in
an incorrect maximal number of keys in the Ordered_key buffer.
  
Solution:
Try to insert each row into the materialized temp table before
collecting statistics, and if the insertion results in a duplicate
row, do not count the current row.

- Changed TABLE->alias to String to get fewer reallocs when alias are used.
- Preallocate some buffers

Changed some String->c_ptr() -> String->ptr() when \0 is not needed.
Fixed wrong usage of String->ptr() when we need a \0 terminated string.
Use my_strtod() instead of my_atof() to avoid having to add \0 to string.
c_ptr() -> c_ptr_safe() to avoid warnings from valgrind.
zr 

sql/event_db_repository.cc:
  Update usage of TABLE->alias
sql/event_scheduler.cc:
  c_ptr() -> c_ptr_safe()
sql/events.cc:
  c_ptr() -> ptr() as \0 was not needed
sql/field.cc:
  Update usage of TABLE->alias
sql/field.h:
  Update usage of TABLE->alias
sql/ha_partition.cc:
  Update usage of TABLE->alias
sql/handler.cc:
  Update usage of TABLE->alias
  Fixed wrong usage of str.ptr()
sql/item.cc:
  Fixed error where code wrongly assumed string was \0 terminated.
sql/item_func.cc:
  c_ptr() -> c_ptr_safe()
  Update usage of TABLE->alias
sql/item_sum.h:
  Use my_strtod() instead of my_atof() to avoid having to add \0 to string
sql/lock.cc:
  Update usage of TABLE->alias
sql/log.cc:
  c_ptr() -> ptr() as \0 was not needed
sql/log_event.cc:
  c_ptr_quick() -> ptr() as \0 was not needed
sql/opt_range.cc:
  ptr() -> c_ptr() as \0 is needed
sql/opt_subselect.cc:
  Update usage of TABLE->alias
sql/opt_table_elimination.cc:
  Update usage of TABLE->alias
sql/set_var.cc:
  ptr() -> c_ptr() as \0 is needed
  c_ptr() -> c_ptr_safe()
sql/sp.cc:
  c_ptr() -> ptr() as \0 was not needed
sql/sp_rcontext.cc:
  
  Update usage of TABLE->alias
sql/sql_base.cc:
  Preallocate buffers
  Update usage of TABLE->alias
sql/sql_class.cc:
  Fix arguments to sprintf() to work even if string is not \0 terminated
sql/sql_insert.cc:
  Update usage of TABLE->alias
  c_ptr() -> ptr() as \0 was not needed
sql/sql_load.cc:
  Preallocate buffers
  Trivial optimizations
sql/sql_parse.cc:
  Trivial optimization
sql/sql_plugin.cc:
  c_ptr() -> ptr() as \0 was not needed
sql/sql_select.cc:
  Update usage of TABLE->alias
sql/sql_show.cc:
  Update usage of TABLE->alias
sql/sql_string.h:
  Added move() function to move allocated memory from one object to another.
sql/sql_table.cc:
  Update usage of TABLE->alias
  c_ptr() -> c_ptr_safe()
sql/sql_test.cc:
  ptr() -> c_ptr_safe()
sql/sql_trigger.cc:
  Update usage of TABLE->alias
  c_ptr() -> c_ptr_safe()
sql/sql_update.cc:
  Update usage of TABLE->alias
sql/sql_view.cc:
  ptr() -> c_ptr_safe()
sql/sql_yacc.yy:
  ptr() -> c_ptr()
sql/table.cc:
  
  Update usage of TABLE->alias
sql/table.h:
  Changed TABLE->alias to String to get fewer reallocs when alias are used.
storage/federatedx/ha_federatedx.cc:
  Use c_ptr_safe() to ensure strings are \0 terminated.
storage/maria/ha_maria.cc:
  Update usage of TABLE->alias
storage/myisam/ha_myisam.cc:
  Update usage of TABLE->alias
storage/xtradb/row/row0sel.c:
  Ensure that null bits in record are properly reset.
  (Old code didn't work as row_search_for_mysql() can be called twice while reading fields from one row.

mysql-test/r/heap_btree.result:
  Test of index over bit firld in hash table.
mysql-test/r/heap_hash.result:
  Test of index over bit firld in hash table.
mysql-test/t/heap_btree.test:
  Test of index over bit firld in hash table.
mysql-test/t/heap_hash.test:
  Test of index over bit firld in hash table.
storage/heap/ha_heap.cc:
  Adding bit field support for heap tables.
storage/heap/hp_create.c:
  Adding bit field support for heap tables.
storage/heap/hp_hash.c:
  Adding bit field support for heap tables.

mysql-test/suite/maria/t/compat_aliases.test:
  Removed column with version number
sql/sql_show.cc:
  Fixed compiler warning

The pushdown condition for the sorted table in a query can be complemented
by the conditions from HAVING. This transformation is done in JOIN::exec
pretty late after the original pushdown condition have been saved in the
field pre_idx_push_select_cond for the sorted table. So this field must
be updated after the inclusion of the condition from HAVING.

- Make mi_open() use less stack space

Avoid doing reallocs
Prealloc some strings / provide extension allocation size to some strings
This gave a 25 % speedup in some mysql-test-run tests.



mysys/safemalloc.c:
  More DBUG_PRINT
sql/net_serv.cc:
  Make all mallocs() look the similar. (just-for-safety fix)
sql/protocol.cc:
  Ensure that communication packet buffer is allocated.
  (It's freed by stored precedures and some DLL statements)
sql/sp.cc:
  Fixed valgrind warning
sql/sql_select.cc:
  Set extent allocation for buffer that has a lot of append() calls.
sql/sql_show.cc:
  Fixed wrong usage of string buffer. Old code worked in test suite 'just-by-chance'
sql/sql_string.cc:
  Call realloc_with_extra_if_needed() in append() functions.
sql/sql_string.h:
  Added 'extra_alloc' member, to specify chunck size for realloc().
  extra_alloc is addaptive to catch cases where preallocation of buffers is not done properly.
  Simplified free() to allow compiler to optimize things better (and to keep things consistent).
  Fixed shrink() to take into account the extra memory added to the Alloced_length in realloc(). This saves us a realloc() per query.
sql/sql_test.cc:
  Set extent allocation for buffer that has a lot of append() calls.
sql/table.cc:
  Set extent allocation for buffer that has a lot of append() calls.

This fixes a bug that gave ER_FILE_TOO_SHORT error when scanning Aria tables.

storage/maria/ma_blockrec.c:
  Changed code so that we update share->state.state.data_file_length after page cache write is done.
  When scanning pages, stop when you are at 'data_file_length'.
  (We can't trust the bitmap as there may be reserved pages in the bitmap that are not yet written).
  This fixes a bug that gave ER_FILE_TOO_SHORT error when scanning Aria tables.
storage/maria/maria_def.h:
  Updated struct for stopping scanning at end of file

Implement os_event_wait_time() for POSIX systems.

In the purge thread, use os_event_wait_time() when sleeping rather than sleep,
and signal the event when server shuts down, so we do not need to wait for
upto 10 seconds until the purge thread wakes up.

Also fix bug that warnings that were pushed after we call set_ok_status() were
not included in the waning count sent to the client in the result packet.

Also in mysqltest, in recursive die() invocation at least print the message
before aborting.

client/mysqltest.cc:
  If we detect recursive die(), at least print the message before aborting.
mysql-test/r/warnings_debug.result:
  Test case.
mysql-test/t/warnings_debug.test:
  Test case.
sql/handler.cc:
  Force generation of a warning with specific debug option, for testing.
sql/protocol.cc:
  Fix wrong DBUG_ENTER
sql/sql_class.h:
  Add method to count warnings pushed after set_ok_status() is called.
sql/sql_error.cc:
  Also count warnings pushed after set_ok_status() is called.
storage/xtradb/include/os0sync.h:
  Implement working os_sync_wait_time() for POSIX.
storage/xtradb/include/srv0srv.h:
  Make the purge thread wait for an event when sleeping, so we can signal it to
  wakeup immediately at shutdown.
storage/xtradb/log/log0log.c:
  Make the purge thread wait for an event when sleeping, so we can signal it to
  wakeup immediately at shutdown.
storage/xtradb/os/os0sync.c:
  Implement working os_sync_wait_time() for POSIX.
storage/xtradb/srv/srv0srv.c:
  Make the purge thread wait for an event when sleeping, so we can signal it to
  wakeup immediately at shutdown.

Fixed a bug in Aria when two threads was inserting into the same table and row page and one thread did an abort becasue of duplicate key.



mysys/thr_lock.c:
  Fixed valgrind warning
sql/sql_base.cc:
  Remove not used variable
storage/maria/ma_bitmap.c:
  Added ma_bitmap_lock() & ma_bitmap_unlock() to protect against two threads using the bitmap at the same time.
  More DBUG_PRINT()
storage/maria/ma_blockrec.c:
  Fixed a bug in Aria when two threads was inserting into the same table and row page and one thread did an abort becasue of duplicate key.
  Fix was that we block other threads to modify the bitmap while we are removing the row with a duplicate key.
storage/maria/ma_blockrec.h:
  Added ma_bitmap_lock() & ma_bitmap_unlock() to protect against two threads using the bitmap at the same time.
storage/maria/maria_def.h:
  Changed flush_all_requested to be a counter.
storage/myisam/mi_locking.c:
  Fixed compiler error on windows (typo).

- Make optimize_wo_join_buffering() handle cases where position->records_read=0 (this
  happens for outer joins that have constant tables inside them). The number of
  0 is not correct (should be 1 because outer join will produce at least a NULL-complemented
  record) but for now we just make it work with incorrect number.