There was no actual execution of the SQL of a pushed derived table,
which caused "r_rows" to be always displayed as 0 and "r_total_time_ms"
to show inaccurate numbers.
This commit makes a derived table SQL to be executed by the storage
engine, so the server is able to calculate the number of rows returned
and measure the execution time more accurately

PROBLEM:
A deadlock was possible when a transaction tried to "upgrade" an already
held Record Lock to Next Key Lock.

SOLUTION:
This patch is based on observations that:
(1) a Next Key Lock is equivalent to Record Lock combined with Gap Lock
(2) a GAP Lock never has to wait for any other lock
In case we request a Next Key Lock, we check if we already own a Record
Lock of equal or stronger mode, and if so, then we change the requested
lock type to GAP Lock, which we either already have, or can be granted
immediately, as GAP locks don't conflict with any other lock types.
(We don't consider Insert Intention Locks a Gap Lock in above statements).

The reason of why we don't upgrage Record Lock to Next Key Lock is the
following.

Imagine a transaction which does something like this:

for each row {
    request lock in LOCK_X|LOCK_REC_NOT_GAP mode
    request lock in LOCK_S mode
}

If we upgraded lock from Record Lock to Next Key lock, there would be
created only two lock_t structs for each page, one for
LOCK_X|LOCK_REC_NOT_GAP mode and one for LOCK_S mode, and then used
their bitmaps to mark all records from the same page.

The situation would look like this:

request lock in LOCK_X|LOCK_REC_NOT_GAP mode on row 1:
// -> creates new lock_t for LOCK_X|LOCK_REC_NOT_GAP mode and sets bit for
// 1
request lock in LOCK_S mode on row 1:
// -> notices that we already have LOCK_X|LOCK_REC_NOT_GAP on the row 1,
// so it upgrades it to X
request lock in LOCK_X|LOCK_REC_NOT_GAP mode on row 2:
// -> creates a new lock_t for LOCK_X|LOCK_REC_NOT_GAP mode (because we
// don't have any after we've upgraded!) and sets bit for 2
request lock in LOCK_S mode on row 2:
// -> notices that we already have LOCK_X|LOCK_REC_NOT_GAP on the row 2,
// so it upgrades it to X
    ...etc...etc..

Each iteration of the loop creates a new lock_t struct, and in the end we
have a lot (one for each record!) of LOCK_X locks, each with single bit
set in the bitmap. Soon we run out of space for lock_t structs.

If we create LOCK_GAP instead of lock upgrading, the above scenario works
like the following:

// -> creates new lock_t for LOCK_X|LOCK_REC_NOT_GAP mode and sets bit for
// 1
request lock in LOCK_S mode on row 1:
// -> notices that we already have LOCK_X|LOCK_REC_NOT_GAP on the row 1,
// so it creates LOCK_S|LOCK_GAP only and sets bit for 1
request lock in LOCK_X|LOCK_REC_NOT_GAP mode on row 2:
// -> reuses the lock_t for LOCK_X|LOCK_REC_NOT_GAP by setting bit for 2
request lock in LOCK_S mode on row 2:
// -> notices that we already have LOCK_X|LOCK_REC_NOT_GAP on the row 2,
// so it reuses LOCK_S|LOCK_GAP setting bit for 2

In the end we have just two locks per page, one for each mode:
LOCK_X|LOCK_REC_NOT_GAP and LOCK_S|LOCK_GAP.
Another benefit of this solution is that it avoids not-entirely
const-correct, (and otherwise looking risky) "upgrading".

The fix was ported from
mysql/mysql-server@bfba840dfa7794b988c59c94658920dbe556075d
mysql/mysql-server@75cefdb1f73b8f8ac8e22b10dfb5073adbdfdfb0

Reviewed by: Marko Mäkelä

"mtr --view-protocol func_math" failed because of a too long
column names imlicitly generated for the underlying expressions.

With --view-protocol they were replaced to "Name_exp_1".

Adding column aliases for these expressions.

MDEV-23187 misses resetting collation connection causing test failures for
10.5+ bugs.

Fix that rpl_slave_state::load() was calling rpl_slave_state::update() without
holding LOCK_slave_state.
Reviewed-by: Monty <monty@mariadb.org>
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

This fixes mdev_26541.test, and the new clean_up_spider.inc will be
useful for other tests where part of deinit_spider does not apply,
e.g. those testing spider initialisation only.

The original code generated a warning in gcc 13.1

make it "query reached <some limit> result may be incomplete"

also make sure all unused error messages are "You should never see it"
and have no translations

btr_node_ptr_max_size(): Handle BINARY(0) and VARBINARY(0)
as special cases, similar to CHAR(0) and VARCHAR(0).

Reviewer: <daniel@mariadb.org>

workaround cmake bug #25044

https://gitlab.kitware.com/cmake/cmake/-/issues/25044

  'long long int'; cast to an unsigned type to negate this value ..
  to itself in Item_func_mul::int_op and Item_func_round::int_op

Problems:

  The code in multiple places in the following methods:
    - Item_func_mul::int_op()
    - longlong Item_func_int_div::val_int()
    - Item_func_mod::int_op()
    - Item_func_round::int_op()

  did not properly check for corner values LONGLONG_MIN
  and (LONGLONG_MAX+1) before doing negation.
  This cuased UBSAN to complain about undefined behaviour.

Fix summary:

  - Adding helper classes ULonglong, ULonglong_null, ULonglong_hybrid
    (in addition to their signed couterparts in sql/sql_type_int.h).

  - Moving the code performing multiplication of ulonglong numbers
    from Item_func_mul::int_op() to ULonglong_hybrid::ullmul().

  - Moving the code responsible for extracting absolute values
    from negative numbers to Longlong::abs().
    It makes sure to perform negation without undefinite behavior:
    LONGLONG_MIN is handled in a special way.

  - Moving negation related code to ULonglong::operator-().
    It makes sure to perform negation without undefinite behavior:
    (LONGLONG_MAX + 1) is handled in a special way.

  - Moving signed<=>unsigned conversion code to
    Longlong_hybrid::val_int() and ULonglong_hybrid::val_int().

  - Reusing old and new sql_type_int.h classes in multiple
    places in Item_func_xxx::int_op().

Fix details (explain how sql_type_int.h classes are reused):

  - Instead of straight negation of negative "longlong" arguments
    *before* performing unsigned multiplication,
    Item_func_mul::int_op() now calls ULonglong_null::ullmul()
    using Longlong_hybrid_null::abs() to pass arguments.
    This fixes undefined behavior N1.

  - Instead of straight negation of "ulonglong" result
    *after* performing unsigned multiplication,
    Item_func_mul::int_op() now calls ULonglong_hybrid::val_int(),
    which recursively calls ULonglong::operator-().
    This fixes undefined behavior N2.

  - Removing duplicate negating code from Item_func_mod::int_op().
    Using ULonglong_hybrid::val_int() instead.
    This fixes undefinite behavior N3.

  - Removing literal "longlong" negation from Item_func_round::int_op().
    Using Longlong::abs() instead, which correctly handler LONGLONG_MIN.
    This fixes undefinite behavior N4.

  - Removing the duplicate (negation related) code from
    Item_func_int_div::val_int(). Reusing class ULonglong_hybrid.
    There were no undefinite behavior in here.
    However, this change allowed to reveal a bug in
    "-9223372036854775808 DIV 1".
    The removed negation code appeared to be incorrect when
    negating +9223372036854775808. It returned the "out of range" error.
    ULonglong_hybrid::operator-() now handles all values correctly
    and returns +9223372036854775808 as a negation for -9223372036854775808.

    Re-recording wrong results for
      SELECT -9223372036854775808 DIV  1;
    Now instead of "out of range", it returns -9223372036854775808,
    which is the smallest possible value for the expression data type
    (signed) BIGINT.

  - Removing "no UBSAN" branch from Item_func_splus::int_opt()
    and Item_func_minus::int_opt(), as it made UBSAN happy but
    in RelWithDebInfo some MTR tests started to fail.

Will re-enable once MDEV-31101 is no longer blocked by MDEV-22979,
as the patch for the latter might fix the former.

- When foreign_key_check is disabled, allowing to modify the
column which is part of foreign key constraint can lead to
refusal of TRUNCATE TABLE, OPTIMIZE TABLE later. So it make
sense to block the column modify operation when foreign key
is involved irrespective of foreign_key_check variable.

Correct way to modify the charset of the column when fk is involved:

SET foreign_key_checks=OFF;
ALTER TABLE child DROP FOREIGN KEY fk, MODIFY m VARCHAR(200) CHARSET utf8mb4;
ALTER TABLE parent MODIFY m VARCHAR(200) CHARSET utf8mb4;
ALTER TABLE child ADD CONSTRAINT FOREIGN KEY (m) REFERENCES PARENT(m);
SET foreign_key_checks=ON;

fk_check_column_changes(): Remove the FOREIGN_KEY_CHECKS while
checking the column change for foreign key constraint. This
is the partial revert of commit 5f1f2fc0
and it changes the behaviour of copy alter algorithm

ha_innobase::prepare_inplace_alter_table(): Find the modified
column and check whether it is part of existing and newly
added foreign key constraint.

spider_db_mbase_util::open_item_func() is a monster function.
It is difficult to maintain while it is expected that we need to
modify it when a new SQL function or a new func_type is added.

We split the function into two distinct functions: one handles the
case of str != NULL and the other handles the case of str == NULL.

This refactoring was done in a conservative way because we do not
have comprehensive tests on the function.

It also fixes MDEV-29447 and MDEV-31338 where field items that are
arguments of a func item may be used before created / initialised.

Note this commit is adapted from a patch by Nayuta for MDEV-26285.

also, add static

This reverts commit a1b6691f.

because #ifdef checks the symbol defined in ssl_compat.h,
so #include <ssl_compat.h> cannot be inside #ifdef

Add printing

Extract the indexed string memcopy pattern in spd_trx.cc to a static
inline function.

Also updated the ubsan check in mdev_26541.test (h/t roel).

This reverts commit 0a99d457
because it should go into only 10.5+

MDEV-31183 binlog_encryption.encrypted_master_switch_to_unencrypted_gtid fails in BB with UBSAN runtime error: downcast of address

sql/log.cc:11101:56: runtime error: downcast of address 0x7f9dc801e9c8 which does not point to an object of type 'Gtid_list_log_event'
sql/sql_repl.cc:1429:12: runtime error: member call on address 0x7f1ca401ea48 which does not point to an object of type 'Gtid_list_log_event'

The problem is that a parallel replica would not immediately stop
running/queued transactions when issued STOP SLAVE. That is, it
allowed the current group of transactions to run, and sometimes the
transactions which belong to the next group could be started and run
through commit after STOP SLAVE was issued too, if the last group
had started committing. This would lead to long periods to wait for
all waiting transactions to finish.

This patch updates a parallel replica to try and abort immediately
and roll-back any ongoing transactions. The exception to this is any
transactions which are non-transactional (e.g. those modifying
sequences or non-transactional tables), and any prior transactions,
will be run to completion.

The specifics are as follows:

 1. A new stage was added to SHOW PROCESSLIST output for the SQL
Thread when it is waiting for a replica thread to either rollback or
finish its transaction before stopping. This stage presents as
“Waiting for worker thread to stop”

 2. Worker threads which error or are killed no longer perform GCO
cleanup if there is a concurrently running prior transaction. This
is because a worker thread scheduled to run in a future GCO could be
killed and incorrectly perform cleanup of the active GCO.

 3. Refined cases when the FL_TRANSACTIONAL flag is added to GTID
binlog events to disallow adding it to transactions which modify
both transactional and non-transactional engines when the binlogging
configuration allow the modifications to exist in the same event,
i.e. when using binlog_direct_non_trans_update == 0 and
binlog_format == statement.

 4. A few existing MTR tests relied on the completion of certain
transactions after issuing STOP SLAVE, and were re-recorded
(potentially with added synchronizations) under the new rollback
behavior.

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

The code in choose_best_splitting() assumed that the join prefix is
in join->positions[].

This is not necessarily the case. This function might be called when
the join prefix is in join->best_positions[], too.
Follow the approach from best_access_path(), which calls this function:
pass the current join prefix as an argument,
"const POSITION *join_positions" and use that.

This reverts commit b05218e0.

This reverts commit 844ddb11.

This fixes MDEV-30967, MDEV-31325, MDEV-31388

This bug could affect queries containing a subquery over splittable derived
tables and having an outer references in its WHERE clause. If such subquery
contained an equality condition whose left part was a reference to a column
of the derived table and the right part referred only to outer columns
then the server crashed in the function st_join_table::choose_best_splitting()
The crashing code was added in the commit ce7ffe61
that made the code of the function sensitive to presence of the flag
OUTER_REF_TABLE_BIT in the KEYUSE_EXT::needed_in_prefix fields.

The field needed_in_prefix of the KEYUSE_EXT structure should not contain
table maps with OUTER_REF_TABLE_BIT or RAND_TABLE_BIT.

Note that this fix is quite conservative: for affected queries it just
returns the query plans that were used before the above mentioned commit.
In fact the equalities causing crashes should be pushed into derived tables
without any usage of split optimization.

Approved by Sergei Petrunia <sergey@mariadb.com>

EXPLAIN EXTENDED should always print the field item used in the left part
of an equality expression from the SET clause of an update statement as a
reference to table column.

Approved by Oleksandr Byelkin <sanja@mariadb.com>

process multibyte characters correctly, don't escape half of the character