Iterative patch improvement. Previously committed patch
caused wrong result on Windows. The previous patch also
broke secure_file_priv for symlinks since not all file
paths which must be compared against this variable are
normalized using the same norm.

The server variable opt_secure_file_priv wasn't
normalized properly and caused the operations
LOAD DATA INFILE .. INTO TABLE ..
and
SELECT load_file(..)
to do different interpretations of the 
--secure-file-priv option.
     
The patch moves code to the server initialization
routines so that the path always is normalized
once and only once.
      
It was also intended that setting the option
to an empty string should be equal to 
lifting all previously set restrictions. This
is also fixed by this patch.

WHERE predicates containing references to empty tables in a
subquery were handled incorrectly by the optimizer when
executing EXPLAIN. As a result, the optimizer could try to
evaluate such predicates rather than just stop with
"Impossible WHERE noticed after reading const tables" as 
it would do in a non-subquery case. This led to valgrind 
errors and crashes.

Fixed the code checking the above condition so that subqueries
are not excluded and hence are handled in the same way as top
level SELECTs.

The server could be tricked to read packets indefinitely if it
received a packet larger than the maximum size of one packet.
This problem is aggravated by the fact that it can be triggered
before authentication.

The solution is to no skip big packets for non-authenticated
sessions. If a big packet is sent before a session is authen-
ticated, a error is returned and the connection is closed.

Problem: "COM_FIELD_LIST is an old command of the MySQL server, before there was real move to only
SQL. Seems that the data sent to COM_FIELD_LIST( mysql_list_fields() function) is not
checked for sanity. By sending long data for the table a buffer is overflown, which can
be used deliberately to include code that harms".

Fix: check incoming data length.

The problem was in an incorrect debug assertion. The expression
used in the failing assertion states that when finding
references matching ORDER BY expressions, there can be only one
reference to a single table. But that does not make any sense,
all test cases for this bug are valid examples with multiple
identical WHERE expressions referencing the same table which
are also present in the ORDER BY list.

Fixed by removing the failing assertion. We also have to take
care of the 'found' counter so that we count multiple
references only once. We rely on this fact later in
eq_ref_table().

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.

during an UPDATE

Extended the fix for bug 29310 to multi-table update:

When a table is being updated it has two set of fields - fields required for
checks of conditions and fields to be updated. A storage engine is allowed
not to retrieve columns marked for update. Due to this fact records can't
be compared to see whether the data has been changed or not. This makes the
server always update records independently of data change.
  
Now when an auto-updatable timestamp field is present and server sees that
a table handle isn't going to retrieve write-only fields then all of such
fields are marked as to be read to force the handler to retrieve them.

The problem is that message resource  (message.rc) is compiled as part of static library
sql.lib rather than with executable mysqld.exe. resource files do not work in static
libraries.

The fix is to add message.rc to mysqld.exe source files list.

Problem: ALTER TABLE ADD INDEX may lead to table copying if there's
numeric field(s) with non-default display width modificator specified.

Fix: compare numeric field's storage lenghts when we decide whether 
they can be considered 'equal' for table alteration purposes.

Previously installed dynamic plugins are explicitly not loaded
on startup with --skip-grant-tables enabled. However, INSTALL
PLUGIN/UNINSTALL PLUGIN commands are allowed, and result in
inconsistent error messages (reporting duplicate plugin or
plugin does not exist).

This patch adds a check for --skip-grant-tables mode, and
returns error ER_OPTION_PREVENTS_STATEMENT to the user when
the above commands are attempted.

Correcting a patch misstake. The converted file path is placed in 'buff' not in opt_secure_file_priv.

Unlocking/locking of LOCK_plugin in ha_ndbcluster.cc not 
needed anymore (but missing from the initial patch).

The server variable opt_secure_file_priv wasn't
normalized properly and caused the operations
LOAD DATA INFILE .. INTO TABLE ..
and
SELECT load_file(..)
to do different interpretations of the 
--secure-file-priv option.

The patch moves code to the server initialization
routines so that the path always is normalized
once and only once.

It was also intended that setting the option
to an empty string should be equal to 
lifting all previously set restrictions. This
is also fixed by this patch.

      
Potential deadlock situation involving LOCK_plugin,
LOCK_global_system_variables and LOCK_status.
      
This patch backports the fix from next-mr, unlocking
LOCK_plugin before calling plugin->init() and
add_status_vars().

Arg_comparator initializes 'comparators' array in case of
ROW comparison and does not free this array on destruction.
It leads to memory leaks.
The fix:
-added Arg_comparator::cleanup() method which frees
 'comparators' array.
-added Item_bool_func2::cleanup() method which calls 
 Arg_comparator::cleanup() method

When re-setting (SET GLOBAL debug='') the GLOBAL debug settings the 
server was not freeing the data elements from the top (initial) frame 
before setting them to 0 without freeing the underlying memory. As these 
are global settings there's a chance that something is there already.
Fixed by :
1. making sure the allocated data are cleaned up before re-setting them
while parsing a debug string
2. making sure the stuff allocated in the global settings is freed on 
shutdown.

            to cleanup open connections

It was possible to UNINSTALL storage engine plugin when binding
between THD object and storage engine is still active (e.g. in
the middle of transaction).

To avoid unclean deactivation (uninstall) of storage engine plugin
in the middle of transaction, additional storage engine plugin
lock is acquired by thd_set_ha_data().

If ha_data is not null and storage engine plugin was not locked
by thd_set_ha_data() in this connection before, storage engine
plugin gets locked.

If ha_data is null and storage engine plugin was locked by
thd_set_ha_data() in this connection before, storage engine
plugin lock gets released.

If handlerton::close_connection() didn't reset ha_data, server does
it immediately after calling handlerton::close_connection().

Note that this is just a framework fix, storage engines must switch
to thd_set_ha_data() from thd_ha_data() if they want to see fit.

Added a filter to mysqlhotcopy to filter out the same tables in the 'mysql' 
database that mysqldump filters out.

Add ignore pattern for valgrind messages.

Several problems addressed:

1. The maximum value for --open_files_limit on non-windows boxes
is now raised to UINT_MAX (the maximum possible without significant
changes in the code). The maximum value on windows is kept to be
2048 due to a known limitation (bug 24509).

2. mysqld_safe now supports --open_files_limit=xx in addition to 
--open-files-limit=xx

3. mysqld_safe always passes through --open[_-]files[_-]limit
to the underlying mysqld. It used to pass it through only if it 
the user running the script has access to the root directory or
there was an --user argument specified.

4. Fixed a prototype in my_file.c to match its counterpart in 
the other #ifdef branch.

mistake in previous push

We should disable const subselect item evaluation because
subselect transformation does not happen in view_prepare_mode
and thus val_...() methods can not be called.

The problem is that we can not use make_cond_for_table().
This function relies on used_tables() condition
which is not set properly for subqueries.
As result subquery is not filtered out.
The fix is to use remove_eq_conds() function instead
of make_cond_for_table() func. 'remove_eq_conds()'
algorithm relies on const_item() value and it allows
to handle subqueries in right way.