When high priority replication slave applier encounters lock conflict in innodb,
it will force the conflicting lock holder transaction (victim) to rollback.
This is a must in multi-master sychronous replication model to avoid cluster lock-up.
This high priority victim abort (aka "brute force" (BF) abort), is started
from innodb lock manager while holding the victim's transaction's (trx) mutex.
Depending on the execution state of the victim transaction, it may happen that the
BF abort will call for THD::awake() to wake up the victim transaction for the rollback.
Now, if BF abort requires THD::awake() to be called, then the applier thread executed
locking protocol of: victim trx mutex -> victim THD::LOCK_thd_data

If, at the same time another DBMS super user issues KILL command to abort the same victim,
it will execute locking protocol of: victim THD::LOCK_thd_data  -> victim trx mutex.
These two locking protocol acquire mutexes in opposite order, hence unresolvable mutex locking
deadlock may occur.

The fix in this commit adds THD::wsrep_aborter flag to synchronize who can kill the victim
This flag is set both when BF is called for from innodb and by KILL command.
Either path of victim killing will bail out if victim's wsrep_killed is already
set to avoid mutex conflicts with the other aborter execution. THD::wsrep_aborter
records the aborter THD's ID. This is needed to preserve the right to kill
the victim from different locations for the same aborter thread.
It is also good error logging, to see who is reponsible for the abort.

A new test case was added in galera.galera_bf_kill_debug.test for scenario where
wsrep applier thread and manual KILL command try to kill same idle victim

trx_update_mod_tables_timestamp(): When implementing
innodb_evict_tables_on_commit_debug, do not evict tables
on which transactional locks exist.

This debug variable was broken since its introduction in
commit 947b0b57.

Problem was that the code didn't handle a transaction created in innodb
as part of a failed mysql_lock_tables()

The issue was:
T1, a parallel slave worker thread, is waiting for another worker thread to
commit. While waiting, it has the MDL_BACKUP_COMMIT lock.
T2, working for mariabackup, is doing BACKUP STAGE BLOCK_COMMIT and blocks
all commits.
This causes a deadlock as the thread T1 is waiting for can't commit.

Fixed by moving locking of MDL_BACKUP_COMMIT from ha_commit_trans() to
commit_one_phase_2()

Other things:
- Added a new argument to ha_comit_one_phase() to signal if the
  transaction was a write transaction.
- Ensured that ha_maria::implicit_commit() is always called under
  MDL_BACKUP_COMMIT. This code is not needed in 10.5
- Ensure that MDL_Request values 'type' and 'ticket' are always
  initialized. This makes it easier to check the state of the MDL_Request.
- Moved thd->store_globals() earlier in handle_rpl_parallel_thread() as
  thd->init_for_queries() could use a MDL that could crash if store_globals
  where not called.
- Don't call ha_enable_transactions() in THD::init_for_queries() as this
  is both slow (uses MDL locks) and not needed.

MDEV-22899 Assertion `field->col->is_binary() || field->prefix_len % field->col->mbmaxlen == 0' failed in dict_index_add_to_cache

is_part_of_a_key(): detect is TEXT field is a part of some key

ha_innobase::can_convert_blob(): now correctly detect whether our blob
is a part of some key. Previously the check didn't work in some cases.

Fix stale virtual field value in 4 cases: when virtual field depends
on row_start/row_end in timestamp/trx_id versioned table. row_start
dep is recalculated in vers_update_fields() (SQL and InnoDB
layer). row_end dep is recalculated on history row insert.

MDEV-22061 InnoDB: Assertion of missing row in sec index row_start upon REPLACE on a system-versioned table

make_versioned_helper() appended new update field unconditionally
while it should check if this field already exists in update vector.

Misc renames to conform versioning prefix. vers_update_fields() name
conforms with sql layer TABLE::vers_update_fields().

           when scrubbing is enabled

buf_read_recv_pages(): Ignore the page to read if it is already
present in the freed ranges.

store_freed_or_init_rec(): Store the ranges only if scrubbing
is enabled or page compressed tablespace.

recv_init_crash_recovery_space(): Add the freed range only when
scrubbing or page compressed tablespace.

range_set::contains(): Search the value is present in ranges.

range_set::remove_if_exists(): Remove the value if exist in ranges.

mtr_t::init(): Handles the scenario that mini-transaction may allocate
a page that had just been freed.

recv_sys_t::parse(): Note down the FREE and INIT redo log irrespective
of STORE value.

Removed innodb_tablespaces_scrubbing from test case

When InnoDB is extending a data file, it is updating the FSP_SIZE
field in the first page of the data file.

In commit 8451e090 (MDEV-11556)
we removed a work-around for this bug and made recovery stricter,
by making it track changes to FSP_SIZE via redo log records, and
extend the data files before any changes are being applied to them.

It turns out that the function fsp_fill_free_list() is not crash-safe
with respect to this when it is initializing the change buffer bitmap
page (page 1, or generally, N*innodb_page_size+1). It uses a separate
mini-transaction that is committed (and will be written to the redo
log file) before the mini-transaction that actually extended the data
file. Hence, recovery can observe a reference to a page that is
beyond the current end of the data file.

fsp_fill_free_list(): Initialize the change buffer bitmap page in
the same mini-transaction.

The rest of the changes are fixing a bug that the use of the separate
mini-transaction was attempting to work around. Namely, we must ensure
that no other thread will access the change buffer bitmap page before
our mini-transaction has been committed and all page latches have been
released.

That is, for read-ahead as well as neighbour flushing, we must avoid
accessing pages that might not yet be durably part of the tablespace.

fil_space_t::committed_size: The size of the tablespace
as persisted by mtr_commit().

fil_space_t::max_page_number_for_io(): Limit the highest page
number for I/O batches to committed_size.

MTR_MEMO_SPACE_X_LOCK: Replaces MTR_MEMO_X_LOCK for fil_space_t::latch.

mtr_x_space_lock(): Replaces mtr_x_lock() for fil_space_t::latch.

mtr_memo_slot_release_func(): When releasing MTR_MEMO_SPACE_X_LOCK,
copy space->size to space->committed_size. In this way, read-ahead
or flushing will never be invoked on pages that do not yet exist
according to FSP_SIZE.

commit 854c219a (MDEV-17301)
broke a constraint: Fixed-length columns cannot be extended in InnoDB
without rebuilding the table.

ha_innobase::can_convert_string(): Correct the condition. We must
not allow any instantaneous change to the length of CHAR columns
measured in characters. For any format other than ROW_FORMAT=REDUNDANT,
we can allow the length in bytes to be extended if mbminlen<mbmaxlen held
before the change of the character set.

m_file[0] not always is a good sample.

Server auto-sets lower_case_file_system value based on default
datadir's behavior instead of instead of using the directory specified
by the user through the configuration file or command line options.

This patch fixes this problem.

Server auto-sets lower_case_file_system value based on default
datadir's behavior instead of instead of using the directory specified
by the user through the configuration file or command line options.

This patch fixes this problem.

In commit 0f90728b (MDEV-16809)
we introduced the configuration option innodb_log_optimize_ddl
for controlling whether native index creation or table-rebuild
in InnoDB should avoid writing full redo log.

Fungo Wang reported that this option is causing occasional failures.
The reason is that pages may be written to data files in an
inconsistent state. Applying log records to such inconsistent pages
may fail.

The solution is to always invoke PageBulk::finish() before page latches
may be released, to ensure that the page contents is in a consistent
state.

Something similar was implemented in MySQL 8.0.13:
mysql/mysql-server@d1254b947354e0f5b7223b09c521bd85f22e1e31

buf_block_t::skip_flush_check: Remove. Suppressing consistency checks
is a bad idea.

PageBulk::needs_finish(): New predicate: Determine whether
PageBulk::finish() must fix up the page.

PageBulk::init(): Clear PAGE_DIRECTION to ensure that needs_finish()
will hold. We change the field from PAGE_NO_DIRECTION to 0
and back without writing redo log. This trick avoids the need
to introduce any new data member to PageBulk.

PageBulk::insert(): Replace some high-level accessors to bypass
debug assertions related to PAGE_HEAP_TOP that we will be violating
until finish() has been executed.

PageBulk::finish(): Tolerate m_rec_no==0. We must invoke this also
on an empty page, to ensure that PAGE_HEAP_TOP is initialized.

PageBulk::commit(): Always invoke finish().

PageBulk::release(), BtrBulk::pageSplit(), BtrBulk::storeExt(),
BtrBulk::finish(): Invoke PageBulk::finish().

page_simple_validate_old(), page_simple_validate_new():
Require PAGE_N_DIR_SLOTS to be at least 2.

MDEV-22721 (commit eba2d10a)
inadvertently introduced an infinite loop.

page_validate(): Remove the infinite loop.

Linux glibc has deprecated ftime resutlting in a compile error on Fedora-32.

Per manual clock_gettime is the suggested replacement. Because my_timer_milliseconds
is a relative time used by largely the perfomrance schema, CLOCK_MONOTONIC_COARSE
is used. This has been available since Linux-2.6.32.

The low overhead is shows in the unittest:

    $ unittest/mysys/my_rdtsc-t
    1..11
    # ----- Routine ---------------
    # myt.cycles.routine          :             5
    # myt.nanoseconds.routine     :            11
    # myt.microseconds.routine    :            13
    # myt.milliseconds.routine    :            18
    # myt.ticks.routine           :            17
    # ----- Frequency -------------
    # myt.cycles.frequency        :    3596597014
    # myt.nanoseconds.frequency   :    1000000000
    # myt.microseconds.frequency  :       1000000
    # myt.milliseconds.frequency  :          1039
    # myt.ticks.frequency         :           103
    # ----- Resolution ------------
    # myt.cycles.resolution       :             1
    # myt.nanoseconds.resolution  :             1
    # myt.microseconds.resolution :             1
    # myt.milliseconds.resolution :             1
    # myt.ticks.resolution        :             1
    # ----- Overhead --------------
    # myt.cycles.overhead         :           118
    # myt.nanoseconds.overhead    :           234
    # myt.microseconds.overhead   :           222
    # myt.milliseconds.overhead   :            30
    # myt.ticks.overhead          :          4946
    ok 1 - my_timer_init() did not crash
    ok 2 - The cycle timer is strictly increasing
    ok 3 - The cycle timer is implemented
    ok 4 - The nanosecond timer is increasing
    ok 5 - The nanosecond timer is implemented
    ok 6 - The microsecond timer is increasing
    ok 7 - The microsecond timer is implemented
    ok 8 - The millisecond timer is increasing
    ok 9 - The millisecond timer is implemented
    ok 10 - The tick timer is increasing
    ok 11 - The tick timer is implemented

In fsp_path_to_space_name(), we would access a byte right before
the start of the string, tripping AddressSanitizer.

This reverts commit d87006a1
and commit a7634281.

Avoid character set conversion for numeric data in this scenario:

SET NAMES utf8;
CREATE OR REPLACE TABLE t1 (a INT);
INSERT INTO t1 VALUES (1);
SELECT a FROM t1;

- Renaming this virtual method store() to store_str():
    store(const char *str, size_t length, CHARSET_INFO *src_cs, CHARSET_INFO *dst_cs)
  We'll be adding more variants of store*() soon. This change will help to avoid
  ambiguities during overloading.

- Adding a helper method store_ident().

- Renaming store_str(const LEX_CSTRING &s...) to store_lex_cstring(),
  to avoid ambiguties during overloading.

- Adding a helper method store() for backward compatibility, to avoid a lot of
  changes in the code now. But eventually we should replace store() to
  non-ambiguius methods store_str() or store_ident().

- Adding a helper method Protocol::needs_conversion() and reusing it
  in two places.

-Wl,-z,relro,-z,now are linker flags and should
be checked as such.

TODO: perform module, exe shared checks separately
rather than a pure linker check.