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

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;

Make role statements work with the PREPARE keyword.

Code was assuming that the keys file would contain at least one valid
key. This caused a Dynamic_array::at(0) call that lead to the crash.

 LOG-SLOW-SLAVE-STATEMENTS NOT DISPLAYED.

        These parameters were moved from the command line options to
        the system variables section. Treatment of the
        opt_log_slow_slave_statements changed to let the
        dynamic change of the variable.

    Problem was that link file (.isl) is also opened using O_DIRECT
    mode and if this fails the whole create table fails on internal
    error.

    Fixed by not using O_DIRECT on link files as they are used only
    on create table and startup and do not contain real data.
    O_DIRECT failures are successfully ignored for data files
    if O_DIRECT is not supported by file system on used
    data directory.

delete deferred events after they're executed
(otherwise they can be executed again for a sub-statement)

See also
commit 0e78d1d
Author: Venkatesh Duggirala <venkatesh.duggirala@oracle.com>
Date:   Wed Mar 20 11:20:47 2013 +0530

    BUG#15850951-DUPLICATE ERROR IN REPLICATION WITH SLAVE
    TRIGGERS AND AUTO INCREMENT

When acting as a Galera receiver node, server startup may take
more than 30 secs (the current default) as it has to wait for
SST/IST operation to complete besides spending some time doing
wsrep recovery.

Fixed by raising the default value of MYSQLD_STARTUP_TIMEOUT
to 60 secs. Also sourced /etc/default/mariadb into the init
script so that it can be used to set MYSQLD_STARTUP_TIMEOUT.

Post-fix: initialize err

Enable replication of CREATE/ALTER/DROP SERVER statements
in Galera cluster.

Allowing assigning of DECIMAL(N,0) values to INT-alike system variables.

10.1 part of the fix

10.0 part of the fix

MDEV-9590: Always print "Engine-independent statistic" warnings and might be filtering columns unintentionally from engines

Do not issue the warning in case we are not going to collect the statistics.

update main.delayed test after 38b89a61
ALTER TABLE ... COMMENT is no longer blocking,
use a different ALTER TABLE variant.

Fixed more cases for MDEV-6282

don't strcpy a string to itself

s/Execute/Query/ to account for --ps-protocol

typo. the code was not matching the comment

fix a buffer overflow in extension_based_table_discovery
(that only happens in debug builds)

Remove Linuxism. 

Works fine with a POSIX-compat shell

don't crash in debug builds. issue an error message on corrupt event