Do not mark subquery as inexpensive when it is not optimized.

        Compiler there is strict about the C/C++ call model
        mixing in function variable assumptions.
        Fixed by adding some 'extern "C"' and changing
        '?' operator with 'if'.

MySQL 5.6 do not work with MariaDB 10.1

Analysis: Problem is that tablespace flags bit DATA_DIR
is on different position on MySQL 5.6 compared to
MariaDB 10.1.

Fix: If we detect that there is difference between dictionary
flags and tablespace flags we remove DATA_DIR flag and compare
again. Remote tablespace is tried to locate even in case
when DATA_DIR flag is not set.

otherwise the plugin does not get compiled if
cmake is called multiple times.

        The check_user_can_set_role() used find_user_exact() to get the
        permissions for the SET ROLE NONE command. Which returned NULL too often,
        for instance when user authenticated as 'user'@'%'.
        Now we use find_user_wild() instead.

Added mysql_to_mariadb.sql script, to change mysql.user tables from
MySQL 5.7 to MariaDB.
After this script is run, one can get the other tables fixed by running
mysql_upgrade

Analysis: When pages in doublewrite buffer are analyzed compressed
pages do not have correct checksum.

Fix: Decompress page before checksum is compared. If decompression
fails we still check checksum and corrupted pages are found.
If decompression succeeds, page now contains the original
checksum.

MariaDB 10.1.x 32-bit binaries.

Problem was the fact that tablespace size was incorrectly
rounded to next extent size (1M).

wrong mutex usage from safe_mutex.
Ensure that LOCK_status is always taken before LOCK_thread_count

Problem was that cost_group_min_max() could not handle if group by was optimized away.

This appears to break some installation, and it did not do anything
useful anyway.

change buffer not empty

Fix: Allow not empty change buffer when innodb_force_recovery >= 5
and output only a warning to error log.

Note: Before using force recovery you should always take backup
of your database.

In some cases, MariaDB 10.0 could write a master.info file that was read
incorrectly by 10.1 and could cause server to fail to start after an upgrade.

(If writing a new master.info file that is shorter than the old, extra
junk may remain at the end of the file. This is handled properly in
10.1 with an END_MARKER line, but this line is not written by
10.0. The fix here is to make 10.1 robust at reading the master.info
files written by 10.0).

Fix several things around reading master.info and read_mi_key_from_file():

 - read_mi_key_from_file() did not distinguish between a line with and
   without an eqals '=' sign.

 - If a line was empty, read_mi_key_from_file() would incorrectly return
   the key from the previous call.

 - An extra using_gtid=X line left-over by MariaDB 10.0 might incorrectly
   be read and overwrite the correct value.

 - Fix incorrect usage of strncmp() which should be strcmp().

 - Add test cases.

This fix also fixes a connection hang when trying to do INSERT DELAYED to a crashed table.

Added crash_mysqld.inc to allow easy crash+restart of mysqld

MDEV-8684 ut relax cpu isnt relaxing

Implement ha_tokudb::cancel_pushed_idx_cond().

This is a conservative fix which follows the approach from the previous
patch for:
BUG#1000051: Query with simple join and ORDER BY takes thousands times...

i.e. __ppc_set_ppr_low rather than 'or 1,1,1'

Problem: We created more than 5 encryption keys for redo-logs.
Idea was that we do not anymore create more than one encryption
key for redo-logs but if existing checkpoint from earlier
MariaDB contains more keys, we should read all of them.

Fix: Add new encryption key to memory structure only if there
currently has none or if we are reading checkpoint from the log.
Checkpoint from older MariaDB version could contain more than
one key.

Using __ppc_get_timebase will translate to mfspr instruction
The mfspr instruction will block FXU1 until complete but the other
Pipelines are available for execution of instructions from other
SMT threads on the same core.

The latency time to read the timebase SPR is ~10 cycles.

So any impact on other threads is limited other FXU1 only instructions
(basically other mfspr/mtspr ops).

Suggested by Steven J. Munroe, Linux on Power Toolchain Architect,
Linux Technology Center
IBM Corporation

Also introduce compiler barrier properly on all architectures.

Bug#18842925 : SET THREAD PRIORITY IN INNODB MUTEX SPINLOOP
Like "pause" instruction for hyper-threading at Intel CPUs,
POWER has special instructions only for hinting priority of hardware-threads.

Approved by Sunny in rb#6256

Backport of the 5.7 fix - https://github.com/mysql/mysql-server/commit/c92102a6ef0f280bfb56e5585fca0d0cdcc34890
(excluded cache line size patch)

Suggestion by Stewart Smith

UT_RELAX_CPU(): Use a compiler barrier.

ut_delay(): Remove the dummy global variable ut_always_false.

RB: 11399
Reviewed-by: Jimmy Yang <jimmy.yang@oracle.com>

Backported from MySQL-5.7 - patch https://github.com/mysql/mysql-server/commit/5e3efb03962838a13afbf1579abbb96aee48ad64

Suggestion by Stewart Smith

Make sure that we read all possible encryption keys from checkpoint
and if log block checksum does not match, print all found
checkpoint encryption keys.

MDEV-9833: Log files are opened using O_DIRECT causing problems if block size != 512

Fix typo.

Fixed calculating pointer to memory allocated for names in numeric format in unpacking procedure.

        The cause of the issue is when DROP DATABASE takes
        metadata lock and is in progress through it's
        execution, a concurrently running CREATE FUNCTION checks
        for the existence of database which it succeeds and then it
        waits on the metadata lock.  Once DROP DATABASE writes to
        BINLOG and finally releases the metadata lock on schema
        object, the CREATE FUNCTION waiting on metadata lock
        gets in it's code path and succeeds and writes to binlog.

1. Fixing Field_time::get_equal_const_item() to pass TIME_FUZZY_DATES
   and TIME_INVALID_DATES to get_time_with_conversion().
   This is needed to make the recursively called Item::get_date() return
   non-NULL values on garbage input. This makes Field_time::get_equal_const_item()
   work consistently with how Item::val_time_packed() works.

2. Fixing Item::get_date() to return TIME'00:00:00' rather than
   DATE'0000-00-00' on empty or garbage input when:
   - TIME_FUZZY_DATES is enabled
   - The caller requested a TIME value (by passing TIME_TIME_ONLY).
   This is needed to avoid conversion of DATE'0000-00-00' to TIME
   in get_time_with_conversion(), which would erroneously try to subtract
   CURRENT_DATE from DATE'0000-00-00' and return TIME'-838:59:59' rather than
   the desired zero value TIME'00:00:00'.

   #1 and #2 fix these type of scripts to return one row with both
   MyISAM and InnoDB, with and without an index on t1.b:

     CREATE TABLE t1 (a ENUM('a'), b TIME, c INT, KEY(b));
     INSERT INTO t1 VALUES ('','00:00:00',0);
     SELECT * FROM t1 WHERE b='';
     SELECT * FROM t1 WHERE a=b;
     SELECT * FROM t1 IGNORE INDEX(b) WHERE b='';
     SELECT * FROM t1 IGNORE INDEX(b) WHERE a=b;

   Additionally, #1 and #2 fix the originally reported in MDEV-9604 crash
   in Item::save_in_field(), because now execution goes through a different
   path, so save_in_field() is called for a Item_time_literal instance
   (which is non-NULL) rather than a Item_cache_str instance (which could
   return NULL without setting null_value).

3. Fixing Field_temporal::get_equal_const_item_datetime() to enable
   equal field propagation for DATETIME and TIMESTAMP in case of
   comparison (e.g. when ANY_SUBST), for symmetry with
   Field_newdate::get_equal_const_item(). This fixes a number of problems
   with empty set returned on comparison to empty/garbage input.
   Now all SELECT queries in this script return one row for MyISAM and InnoDB,
   with and without an index on t1.b:

     CREATE TABLE t1 (a ENUM('a'), b DATETIME, c INT, KEY(b));
     INSERT INTO t1 VALUES ('','0000-00-00 00:00:00',0);
     SELECT * FROM t1 WHERE b='';
     SELECT * FROM t1 WHERE a=b;
     SELECT * FROM t1 IGNORE INDEX(b) WHERE b='';
     SELECT * FROM t1 IGNORE INDEX(b) WHERE a=b;