Let us avoid excessive allocation of explicit record locks.

spatial_index_info: Replaces index_tuple_info_t. Always take
a memory heap as a parameter to the member functions.
Remove pointer indirection for m_dtuple_vec.

spatial_index_info::add(): Duplicate any PRIMARY KEY fields that would
point to within ext->buf because that buffer will be allocated in
a shorter-lifetime memory heap.

Every operation that is going to write redo log is supposed to
invoke log_free_check() before acquiring any latches. If there
is a risk of log buffer overrun, a log checkpoint would be
triggered by that call.

ibuf_merge_space(), ibuf_merge_in_background(),
ibuf_delete_for_discarded_space(): Invoke log_free_check()
when the current thread is not holding any page latches.

Unfortunately, in lower-level code called from ibuf_insert()
or ibuf_merge_or_delete_for_page(), some page latches may be
held and a call to log_free_check() could hang.

ibuf_set_bitmap_for_bulk_load(): Use the caller's mini-transaction.
The caller should have invoked log_free_check() while not holding
any page latches.

Something appears to be broken in the DBUG subsystem.
Let us remove frequent calls to it from the InnoDB internal SQL interpreter
that is used in the purge of transaction history.

The DBUG_PRINT in que_eval_sql() can remain for now, because those
operations are much less frequent.

This fixes up commit e3c39c0b

InnoDB crash recovery can run out of memory before
commit 50324ce6 in
MariaDB Server 10.5.

Let us disable some frequently failing recovery tests
in earlier versions.

Not creating explicit record locks will speed up the test.

Also, disable the use of InnoDB persistent statistics in the test of
MDEV-27270 to avoid intermittent failures in 10.6 or later
(after commit 9608773f)
due to the nondeterministic scheduling of STATS_AUTO_PERSISTENT.

The file plugin_exports became unused in
commit fec844ac

- mariabackup fails to assign srv_undo_space_id_start when the
dedicated undo tablespaces are disabled

Problem:-
  We are able to insert duplicate value in table because cmp_binary_offset
  is not able to differentiate between NULL and empty string. So
  check_duplicate_long_entry_key is never called and we don't check for
  duplicate.
Solution
  Added a if condition with is_null() on field which can differentiate
  between NULL and empty string.

When trying to output stacktrace, and addr2line is not installed, the
child process forked by start_addr2line_fork() will fail to do exec(),
and finish with exit(1).

There is a problem with exit() though - it runs exit handlers,
and for the forked copy of crashing process, it is a bad idea.

In 10.5+ code for example, exit handlers include
tpool::task_group static destructors, and it will hang infinitely
waiting for completion of the outstanding tasks.

The fix is to use _exit() instead, which skips the execution of exit
handlers

Make sure that EXPLAIN object allocated on runtime arena.

MDEV-29924 Assertion `(((nr) % (1LL << 24)) % (int) log_10_int[6 - dec]) == 0' failed in my_time_packed_to_binary on SELECT when using TIME field

when assigning the cached item to the Item_cache for the first time
make sure to use Item_cache::setup(), not Item_cache::store().
Because the former copies the metadata (and allocates memory, in case
of Item_cache_row), and Item_cache::decimal must be set for
comparisons to work correctly.

Deallocation of TABLE_LIST::dt_handler and TABLE_LIST::pushdown_derived
was performed in multiple places if code. This not only made the code
more difficult to maintain but also led to memory leaks and
ASAN heap-use-after-free errors.
This commit puts deallocation of TABLE_LIST::dt_handler and
TABLE_LIST::pushdown_derived to the single point - JOIN::cleanup()

/usr/ports/pobj/mariadb-10.9.3/mariadb-10.9.3/mysys/my_lock.c:183:7: warning: incompatible function pointer types assigning to 'sig_return' (aka 'void (*)(void)') from 'void (*)(int)' [-Wincompatible-function-pointer-types]
      ALARM_INIT;
      ^~~~~~~~~~
/usr/ports/pobj/mariadb-10.9.3/mariadb-10.9.3/include/my_alarm.h:43:16: note: expanded from macro 'ALARM_INIT'
                        alarm_signal=signal(SIGALRM,my_set_alarm_variable);
                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/ports/pobj/mariadb-10.9.3/mariadb-10.9.3/mysys/my_lock.c:189:7: warning: incompatible function pointer types passing 'sig_return' (aka 'void (*)(void)') to parameter of type 'void (*)(int)' [-Wincompatible-function-pointer-types]
      ALARM_END;
      ^~~~~~~~~
/usr/ports/pobj/mariadb-10.9.3/mariadb-10.9.3/include/my_alarm.h:44:41: note: expanded from macro 'ALARM_END'
                                              ^~~~~~~~~~~~
/usr/include/sys/signal.h:199:27: note: passing argument to parameter here
void    (*signal(int, void (*)(int)))(int);
                             ^
2 warnings generated.

The prototype is the same for all of the *BSD's.

void
(*signal(int sigcatch, void (*func)(int sigraised)))(int);

Per the code my_set_max_open_files 3 lines earlier, we attempt
to set the nofile (number of open files), rlimit to max_open_files.

We should use this in the warning because wanted_files may not
be the number.

Fix a couple of build warnings that fire with CONNECT engine.

MDEV-28822 Table from older version requires table rebuild when adding column to table with multi-column index

This problem was earlier fixed in 10.4 by the patch for MDEV-29481.

Adding MTR tests only.