Starting with commit da094188 (MDEV-24393),
MariaDB will no longer acquire advisory file locks on InnoDB data
files by default, because it would create a large number of
entries in Linux /proc/locks.

The motivation for acquiring the file locks is to prevent accidental
concurrent startup of multiple server processes on the same data files.
Such mistake still turns out to be relatively common, based on
corruption bug reports from the community.

To prevent corruption due to concurrent startup attempts, the
Aria storage engine would unconditionally acquire an advisory lock
on one of its log files.

Solution: InnoDB will always lock its system tablespace files.
(Ever since commit 685d958e
the InnoDB log file will not necessarily be open while the
server is running, because it can be accessed via memory-mapped I/O.)

If more protection is desired, then the option --external-locking
can be used.

The mandatory advisory lock also fixes intermittent failures of
some crash recovery tests. It turns out that when the mtr test harness
kills and restarts the server, it will not actually ensure that the
old process has terminated before starting the new one.

This bug could cause a crash of the server when executing queries containing
ANY/ALL predicands with redundant subqueries in GROUP BY clauses.
These subqueries are eliminated by remove_redundant_subquery_clause()
together with elimination of GROUP BY list containing these subqueries.
However the references to the elements of the GROUP BY remained in the
JOIN::all_fields list of the right operand of of the ALL/ANY predicand.
Later these references confused make_aggr_tables_info() when forming
proper execution structures after ALL/ANY predicands had been replaced
with expressions containing MIN/MAX set functions.
The patch just removes these references from JOIN::all_fields list used
by the subquery of the ALL/ANY predicand when its GROUP BY clause is
eliminated.

Approved by Oleksandr Byelkin <sanja@mariadb.com>

followup for 4bc34ef3

prepare_inplace_add_virtual(): Over-estimate the size of the arrays
by not subtracting table->s->virtual_fields (which may refer to
stored, not virtual generated columns). InnoDB only distinguishes
virtual columns.

- Import tablespace re-evicts and reload the table definition. During that
time, innodb has to load the table even though the secondary fts index
marked as corrupted

- InnoDB should ignore the single word followed by apostrophe while
tokenising the document. Example is that if the input string is O'brien
then right now, InnoDB seperates into two tokens as O, brien. But
after this patch, InnoDB can ignore the token 'O' and consider
only 'brien'.

The logic on Windows was originally simplified in
commit 4bca1a78
for storage/xtradb and later in
commit 6304c0bf
for storage/innobase.

Unlike GCC, clang could optimize away alloca() and thus the
ALLOCATE_MEM_ON_STACK() instrumentation. To make it harder, let us
invoke a non-inline function on the entire allocated buffer.

The hang may be caused by a 1pc branch that was fixed by MDEV-26031 in
10.6 and up. That commit did not look relevant in 10.5 and below
so  was not pushed to the low branches.

To possibly tackle the reported issue
the MDEV-26031 is backported now with a test that
unlike 10.6 does not expose the former bug in 10.5.
It is only needed for checking a refined logics
inside MYSQL_BIN_LOG::write_transaction_to_binlog.
The latter is made to do away with xid-unlogging (which is suspected
to have been at fault) for xid-less transaction.

This commit replaces sprintf(buf, ...) with
snprintf(buf, sizeof(buf), ...),
specifically in the "easy" cases where buf is allocated with a size
known at compile time.

The changes make sure we are not write outside array/string bounds which
will lead to undefined behaviour. In case the code is trying to write
outside bounds - safe version of functions simply cut the string
messages so we process this gracefully.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the BSD-new
license.  I am contributing on behalf of my employer Amazon Web Services,
Inc.

bsonudf.cpp warnings cleanup by Daniel Black

Reviewer: Daniel Black

Problem:
=======

This patch addresses two issues:

 1. An incident event can be incorrectly reported for transactions
which are rolled back successfully. That is, an incident event
should only be generated for failed “non-transactional transactions”
(i.e., those which modify non-transactional tables) because they
cannot be rolled back.

 2. When the mariadb slave (error) stops at receiving the incident
event there's no description of what led to it. Neither in the event
nor in the master's error log.

Solution:
========

Before reporting an incident event for a transaction, first validate
that it is “non-transactional” (i.e. cannot be safely rolled back).
To determine if a transaction is non-transactional,
  lex->stmt_accessed_table(LEX::STMT_WRITES_NON_TRANS_TABLE)
is used because it is set previously in
THD::decide_logging_format().

Additionally, when an incident event is written, write an error
message to the server’s error log to indicate the underlying issue.

Reviewed by:
===========
Andrei Elkin <andrei.elkin@mariadb.com>

Spotted by Thirunarayanan Balathandayuthapani.

dict_load_foreigns(): Use a correctly sized buffer for the maximum-length
SYS_FOREIGN.ID. In case of overflow, do not crash the server but instead
return DB_CORRUPTION.

    This commit is a fixup for MDEV-28762

    Analysis: Some recursive json functions dont check for stack control
    Fix: Add check_stack_overrun(). The last argument is NULL because it is not
    used

Analysis: Some recursive json functions dont check for stack control
Fix: Add check_stack_overrun(). The last argument is NULL because it is not
used

Passing $opt_parallel as $childs is wrong: child can be killed before
it connects and you will never decrement $childs for this.

Another problem is (and that is the cause of this bug): child can be
killed and never close server socket. This can happen f.ex. after
unmaskable KILL signal. In such case the socket is closed by reaping
the child but that never happens inside reading the socket loop in
run_test_server().

The proper design is the waitless reap of children inside the socket
loop and if there is no more children we finish the socket loop. Since
there is Windows variation where we don't control the children via
waitpid(), all the clients must normally close the socket and only
this can finish the socket loop. For Unix variation we reckon that
case as all children closed the socket but not all yet died and for
that we do final waiting waitpid() (was done before the patch as
well).

To be more complete, we now handle 3 end-of-game scenarios in Unix:

   1. all children closed socket, all children died: everything is
      handled by the socket loop;

   2. all children closed socket, not all yet died: we wait for alive
      children to die after exiting the socket loop;

   3. not all children closed socket, all children died: everything is
      handled by the socket loop.

For Windows end-of-game scenario is only one:

   All children close the socket.

The case for "Unknown process $ret_pid exited" is never known to be
valid. Such state is not documented for waitpid().

66832e3a introduced change that prints core dumps in very detailed
format. That's completely out of user-friendliness but serves as a
measure for debugging hard-reproducible bugs.

The proper way to implement this:

  1. it must be controlled by command-line and environment variable;
  2. detailed traces must be default for buildbots only, for user
     invocations normal stack traces should be printed.

Options for control are: MTR_PRINT_CORE and --print-core that accept
the following values:

  no	         Don't print core
  short	       	 Print stack trace of failed thread
  medium	 Print stack traces of all threads
  detailed       Print all stack traces with debug context
  custom:<code>  Use debugger commands <code> to print stack trace

Default setting is: short (see env_or_default() call in pre_setup())

For environment variable wrong values are silently ignored (falls back
to default setting, see env_or_default()).

Command-line option --print-core (or -C) overrides environment
variable. Its default value is 'short' if not specified explicitly
(same env_or_default() call in pre_setup()). Explicit values are
checked for validity.

--print-method option can specify by which debugger we print
cores. For Windows there is only one choice: cdb. For Unix the values
are: gdb, dbx, lldb, auto. Default value is: auto

In 'auto' we try to use all possible debuggers until success.

setup_boot_args(), setup_client_args(), setup_args() traversing
datastructures on each invocation. Even if performance is not
important to perl script (though it definitely saves some CO2), this
nonetheless provokes some code-reading questions. Reading and
debugging such code is not convenient.

The better way is to prepare all the data in advance in an easily
readable form as well as do the validation step before any further
processing.

Use mtr_report() instead of die() like the other code does.

TODO: do_args() does even more data processing magic. Prepare that
data according the above strategy in advance in pre_setup() if possible.

GetOpt::Long bundling option for convenient one-char verbosity levels:

  -v    General verbosity (file and execute operations)
  -vv   High verbosity (algorithmic considerations)
  -vvv  Debug verbosity (anything else)

Do we still need this Sun Studio hack?

On all Unix platforms, link libexecinfo as system library,
if it contains backtrace_symbols_fd function, and libc does not contain
this function

Also remove cmake/os/OpenBSD.cmake, as after the fix it serves no purpose.

MDEV-26546 SIGSEGV's in spider_db_connect on SHOW TABLE and spider_db… …_mbase::connect (and SIGSEGV's in check_vcol_forward_refs and inline_mysql_mutex_lock)

Not the SPIDER issue - happens to INSERT DELAYED.
the field::make_new_field does't copy the LONG_UNIQUE_HASH_FIELD
flag to the new field. Though the Delayed_insert::get_local_table
copies the field->vcol_info for this field. Ad a result
the parse_vcol_defs doesn't create the expression for that column
so the field->vcol_info->expr is NULL. Which leads to crash.
Backported fix for this from 10.5 - the flagg added in the
Delayed_insert::get_local_table.

Another problem with the USING HASH key is thst the
parse_vcol_defs modifies the table->keys content. Then the same
parse_vcol_defs is called on the table copy that has keys already
modified. Backported fix for that from 10.5 - key copying added
tot the Delayed_insert::get_local_table.

Finally - the created copy has to clear the expr_arena as
this table is not in the thd->open_tables list so won't be
cleared automatically.

Remove table_count from Query_tables_list (not used, moved to MYSQL_LOCK).

Rename table_count from LEX to avoid mixing it with other counters of tables.