On FreeBSD liblz4 is installed in /usr/local/lib.
Groonga uses pkg_check_modules to check for liblz4 (that is, pkg-config),
and then it used to set for libgroonga.a

  link_directories({$LIBLZ4_LIBRARY_DIRS})
  target_link_libraries(... ${LIBLZ4_LIBRARIES})

Now groonga is a static library, linked into ha_mroonga.so. CMake won't
link dynamic liblz4.so into libgroonga.a, instead it'll pass it as a
dependency and will link it into ha_mroonga.so. Fine so far. But it will
not pass link_directories from the static library as a dependency,
so ha_mroonga.so won't find liblz4.so

As suggested on cmake mailing list (e.g.
here: http://public.kitware.com/pipermail/cmake/2011-November/047468.html)
we switch to use the full path to liblz4.so, instead of the -l/-L pair.

in ALTER TABLE ... DROP KEY, ADD KEY, don't forget to compare old
and new keys' block sizes. If they differ - the key definition has changed.

The problem was that waiting for pause_for_ftwrl was done before
event_group was completed. This caused rpl_pause_for_ftwrl() to wait
forever during FLUSH TABLES WITH READ LOCK.
Now we only wait for FLUSH TABLES WITH READ LOCK when we are changing
to a new event group.

Protection added to reopen_file() and new_file_impl().

Without this we could get an assert in fn_format() as name == 0,
because the file was closed and name reset, atthe same time
new_file_impl() was called.

 is starting.

This is needed as if we kill the START SLAVE thread too early during
shutdown then the IO_THREAD or SQL_THREAD will not have time to properly
initlize it's replication or THD structures and clean_up() will try to
delete master_info structures that are still in use.

Added mutex_lock/mutex_unlock of mutex that is to be destroyed in
wait_for_commit::reinit() in a similar fashion that we do in
~wait_for_commit

This solves some possible dead locks when one calls stop slave while slave
is starting.

The reason for this is that stop slave takes LOCK_active_mi over the
whole operation while some slave operations will also need LOCK_active_mi
which causes deadlocks.

Fixed by introducing object counting for Master_info and not taking
LOCK_active_mi over stop slave or even stop_all_slaves()

Another benefit of this approach is that it allows:
- Multiple threads can run SHOW SLAVE STATUS at the same time
- START/STOP/RESET/SLAVE STATUS on a slave will not block other slaves
- Simpler interface for handling get_master_info()
- Added some missing unlock of 'log_lock' in error condtions
- Moved rpl_parallel_inactivate_pool(&global_rpl_thread_pool) to end
  of stop_slave() to not have to use LOCK_active_mi inside
  terminate_slave_threads()
- Changed argument for remove_master_info() to Master_info, as we always
  have this available
- Fixed core dump when doing FLUSH TABLES WITH READ LOCK and parallel
  replication. Problem was that waiting for pause_for_ftwrl was not done
  when deleting rpt->current_owner after a force_abort.

- Removed not used variables
- Added __attribute__()
- Added static to some local functions
  (gcc 5.4 gives a warning for external functions without an external definition)

As suggested in MySQL Bug#58536, increase the limit in this
debug assertion in order to avoid false positives on heavily
loaded systems.

This removes functionality of where ./mtr --mem /tmp/dir could be a directory.

Now MTR_MEM=/tmp/dir ./mtr is needed.

The case where MTR_MEM=/tmp/dir ./mtr --mem has the equivalent effect.
Signed-off-by: Daniel Black <daniel.black@au.ibm.com>

--mem works better as a pure flag, because it can be followed by command-line arguments (test names). If the option is allowed to have a value, the test name which directly follows it will be treated as the option value instead. It is possible to implement workarounds to avoid this, but they would not be completely reliable, and there is no practical purpose of such extension of functionality to justify them.

The function mysql_derived_merge() erroneously did not mark newly formed
AND formulas in ON conditions with the flag abort_on_null. As a result
not_null_tables() calculated incorrectly for these conditions. This
could prevent conversion of embedded outer joins into inner joins.

Changed a test case from table_elim.test to preserve the former execution
plan.

MDEV-5999 MySQL Bug#12766319 - 61865: RENAME USER DOES NOT WORK CORRECTLY - REQUIRES FLUSH PRIVILEGES

use update_hostname() to update the hostname.
test case comes from

  commit 0abdeed1d6d
  Author: gopal.shankar@oracle.com <>
  Date:   Thu Mar 29 00:20:54 2012 +0530

    Bug#12766319 - 61865: RENAME USER DOES NOT WORK CORRECTLY -
                          REQUIRES FLUSH PRIVILEGES

FUNCTIONS/PRIVILEGES DIFFERENTLY'.

The problem was that attempt to grant EXECUTE or ALTER
ROUTINE privilege on stored procedure which didn't exist
succeed instead of returning an appropriate error like
it happens in similar situation for stored functions or
tables.

The code which handles granting of privileges on individual
routine calls sp_exist_routines() function to check if routine
exists and assumes that the 3rd parameter of the latter
specifies whether it should check for existence of stored
procedure or function. In practice, this parameter had
completely different meaning and, as result, this check was
not done properly for stored procedures.

This fix addresses this problem by bringing sp_exist_routines()
signature and code in line with expectation of its caller.

it went out of support five years ago

It's too plainful to require <my_config.h> to be included first
for third-party storage engines. And anyway, some source files
might not include <my_config.h> at all, so there is no guarantee
that all parts of the binary will see identical definitions of system
structures (e.g. struct stat).

Define _FILE_OFFSET_BITS on the compiler's command line instead.

fix_for_comment() uses a static buffer. cannot have two
fix_for_comment() calls as arguments to one printf().

it was race condition prone. instead use either a pair of my_delete()
calls with already resolved paths, or a safe high-level function
my_handler_delete_with_symlink(), like MyISAM and Aria already do.

don't realpath() twice

At least it would be a compilation failure with -DDONT_ALLOW_SHOW_COMMANDS.
Otherwise it only confuses ctags to ignore ~75% of sql_parse.cc

TOCTOU bug. The path is checked to be valid, symlinks are resolved.
Then the resolved path is opened. Between the check and the open,
there's a window when one can replace some path component with a
symlink, bypassing validity checks.

Fix: after we resolved all symlinks in the path, don't allow open()
to resolve symlinks, there should be none.

Compared to the old MyISAM/Aria code:
* fastpath. Opening of not-symlinked files is just one open(),
  no fn_format() and lstat() anymore.
* opening of symlinked tables doesn't do fn_format() and lstat() either.
  it also doesn't to realpath() (which was lstat-ing every path
  component), instead if opens every path component with O_PATH.
* share->data_file_name stores realpath(path) not readlink(path). So,
  SHOW CREATE TABLE needs to do lstat/readlink() now (see ::info()),
  and certain error messages (cannot open file "XXX") show the real
  file path with all symlinks resolved.

Remove maria_test_invalid_symlink() and myisam_test_invalid_symlink(),
introduce mysys_test_invalid_symlink(). Other engines might need it too

Don't let my_register_filename() fail because strdup() failed. Better to
have NULL for a filename, then to fail the already successful open().

Filenames are only used for error reporting and there was already code
to ignore OOMs (my_fdopen()) and to cope with missing filenames
(my_filename()).

my_realpath() ignores MY_xxx flags anyway

While DEBUG_SYNC doesn't make sense without a valid THD, it might
be put in the code that's invoked both within and outside of a
THD context (e.g. in maria_open(), there is no THD during recovery).

Workaround for join_cache + index on vcols + keyread bug.
Initialize the record to avoid caching garbage in non-read fields.

A proper fix (do not cache non-read fields at all) is done in 10.2
in commits 5d7607f3..8d99166c

mysql_prune_stmt_list() was walking the list following
element->next pointers, but inside the loop it was invoking
list_add(element) that modified element->next. So, mysql_prune_stmt_list()
failed to visit and reset all elements, and some of them were left
with pointers to invalid MYSQL.