after b9d64989 the test for MDEV-16962 is not suitable anymore
(and probably the bug is not reproducible).

1) Checked presence of mysys_var.
2) Removed unneeded thd_clear_errors,
  its content added to THD::change_user.

When you only need view structure, don't call handle_derived with
DT_CREATE and rely on its internal hackish check to skip DT_CREATE.
Because handle_derived is called from many different places,
and this internal hackish check is indiscriminative.

Instead, just don't ask handle_derived to do DT_CREATE
if you don't want it to do DT_CREATE.

galera_var_wsrep_on_off : Add wait conditions to make sure DDL is
replicated before continuing.

wsrep.[variables|variables_debug] :  Remove unnecessary parts
and add check to correct number of variables or skip

galera_ssl_reload: Add version check and SSL checks.

Fix a race condition in the testcase. The testcase assumed that
State='Sending data' means that the thread is already in an
InnoDB lock wait. This is not case, there is a gap between the
state changing to Sending data and execution reaching the point
where it is waiting for a lock.

Use a more precise check instead, through I_S.INNODB_TRX.

The problem was caused by the following scenario:

Subquery's table has two indexes, KEY a(a), KEY a_b(a,b)

- LATERAL DERIVED optimization decides to use index a.
  = The subquery uses ref access over key a.
- test_if_skip_sort_order() sees that KEY a_b satisfies the
  subquery's GROUP BY clause, and attempts to switch to it.
  = It fails to do so, because KEYUSE objects for index a_b
    are switched off.

Fixed by disallowing to change the ref access key if it uses KEYUSE
objects injected by LATERAL DERIVED optimization.

Problem:
========
180511 11:07:58 [ERROR] Slave I/O: Unexpected master's heartbeat data:
heartbeat is not compatible with local info;the event's data: log_file_name
mysql-bin.000009 log_pos 1054262041, Error_code: 1623

Analysis:
=========
In replication setup when master server doesn't have any events to send to
slave server it sends an 'Heartbeat_log_event'. This event carries the
current binary log filename and offset details. The offset values is stored
within 4 bytes of event header. When the size of binary log is higher than
UINT32_MAX the log_pos values will not fit in 4 bytes memory.  It overflows
and hence slave stops with an error.

Fix:
===
Since we cannot extend the common_header of Log_event class, a greater than
4GB value of Log_event::log_pos is made to be transported with a HeartBeat
event's sub-header.  Log_event::log_pos in such case is set to zero to
indicate that the 8 byte sub-header is allocated in the event.

In case of cross version replication following behaviour is expected

OLD - Server without fix
NEW - Server with fix

OLD<->NEW : works bidirectionally as long as the binlog offset is
            (normally) within 4GB.

When log_pos > UINT32_MAX
OLD->NEW  : The 'log_pos' is bound to overflow and NEW slave may report
            an invalid event/incompatible heart beat event error.
NEW->OLD  : Since patched server sets log_pos=0 on overflow, OLD slave will
            report invalid event error.

- Fixing post-push failure of innodb_fts_misc_1 test case.

InnoDB tries to fetch the deleted doc ids for discarded
tablespace. In i_s_fts_deleted_generic_fill(), InnoDB needs
to check whether the table is discarded or not before fetching
deleted doc ids.

fil_ibd_load(): Remove a message that is basically saying that
everything works as expected. The other "Ignoring data file" message
about the presence of an extraneous file will be retained
(and expected by the test innodb.log_file_name).

This reverts commit 8880dff2.

MDEV-22265 Connect string character limit too small for full 64 character InnoDB table-name limit when using ad-hoc Spider server definitions.

Fix length for getting default table name.

This commits replaces the call of the function setup_tables() with
a call of the function setup_tables_and_check_access() in the method
Multiupdate_prelocking_strategy::handle_end().
There is no known bug that would require this change. However the change
aligns this piece of code with the code existed before the patch for
MDEV-24823.

MDEV-25501 routine_definition in information_schema.routines loses tablename if it starts with an _ and is not backticked

remove code duplication in Lex_input_stream::scan_ident_middle(),
make sure identifiers are always use the same code path whether
they start form an underscore or not.

Attempt to build MariaDB server on MacOS could result in
compilation errors like the following one:

  In file included from server-10.2/storage/perfschema/cursor_by_account.cc:28:
  In file included from server-10.2/include/my_global.h:287:
  In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.3.sdk/usr/include/c++/v1/math.h:309:
  In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.3.sdk/usr/include/c++/v1/type_traits:418:
    server-10.2/version:1:1: error: expected unqualified-id

    MYSQL_VERSION_MAJOR=10
    ^
  server-10.2/build.dir/include/my_config.h:529:29: note: expanded from macro 'MYSQL_VERSION_MAJOR'

This kind of compiler errors occur by the reson that compiler's system headers
contain the directive '#include <version>' and a compiler is invoked
with -I${CMAKE_SOURCE_DIR}.

The MariaDB source code root directory contains the file VERSION that is handled
by the compiler during processing the directive #include <version>
since file names on MacOS are case insensetive, so version and VERSION is treated as
the same file name.

To fix the issue the source code root directory should be removed from a list
of directories used by the compiler for include search path.

The problem is that sharing default expression among set instruction
leads to attempt access result field of function created in
other instruction runtime MEM_ROOT and already freed
(a bit different then MySQL problem).

Fix is the same as in MySQL (but no optimisation for constant), turn
DECLARE a, b, c type DEFAULT expr;
to
DECLARE a type DEFAULT expr, b type DEFAULT a, c type DEFAULT a;

This patch changes statement rollback for streaming replication.
Previously, a statement rollback was turned into full transaction
rollback in the case where the transaction had already replicated a
fragment. This was introduced in the initial implementation of
streaming replication due to the fact that we do not have a mechanism
to perform a statement rollback on the applying side.
This policy is however overly pessimistic, causing full rollbacks even
in cases where a local statement rollback, would not require a
statement rollback on the applying side. This happens to be case when
the statement itself has not replicated any fragments.
So the patch changes the condition that determines if a statement
rollback should be turned into a full rollback accordingly.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

Removed explicit InnoDB monitor startup and used just functions
to print current lock information.

Problem was that we should skip strict password validation on
applier nodes similarly as is done for slave nodes.

Replace unnecessary sleeps with real wait_conditions to make
sure correct cluster sizes.

Removed redundant code for BF abort transaction in `thr_lock.cc`.

TOI operations will ignore provided lock_wait_timeout and use `LONG_TIMEOUT`
until operation is finished.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

don't try to lowercase a db name if it's zero-length.
(empty_lex_str is not writable, even db.str[0]=0 will fail)

Relax the assert condition. A locked table that did existed prior to
CREATE IF NOT EXIST, retains the MDL_NO_SHARED_READ_WRITE MDL lock prio.

Problem:
=======
  InnoDB alter fails before applying instant operation. So rollback
assigns wrong column to the secondary index field. It leads
to the assert failure in the consecutive alter.

Fix:
===
  InnoDB shouldn't do rollback of instant operation when it fails
before applying instant operation.