If async slave thread (slave SQL handler), becomes a BF victim, it may occasionally happen that rollbacker thread is used to carry out the rollback instead of the async slave thread.
This can happen, if async slave thread has flagged "idle" state when BF thread tries to figure out how to kill the victim.
The issue was possible to test by using a galera cluster as slave for external master, and issuing high load of conflicting writes through async replication and directly against galera cluster nodes.
However, a deterministic mtr test for the "conflict window" has not yet been worked on.

The fix, in this patch makes sure that async slave thread state is never set to IDLE. This prevents the rollbacker thread to intervene.
The wsrep_query_state change was refactored to happen by dedicated function to make controlling the idle state change in one place.

MDEV-22006 runtime error: null pointer passed as argument 2, which is declared to never be null in JOIN::copy_ref_ptr_array()

Do not memcpy() a zero-length buffer

		redo log during recovery

- InnoDB unnecessarily reads the page even though it has fully initialized
buffered redo log records. Allow the page initialization redo log to
apply for the page in buf_page_get_gen() during recovery.
- Renamed buf_page_get_gen() to buf_page_get_low()
- Newly added buf_page_get_gen() will check for buffered redo log for
the particular page id during recovery
- Added new function buf_page_mtr_lock() which basically latches the page
for the given latch type.
- recv_recovery_create_page() is inline function which creates a page
if it has page initialization redo log records.

MDEV-19658 UBSAN: runtime error: load of value 2779096485, which is not a valid value for type 'enum_binlog_format'

This is an uninitialized read.

THD::THD: initialize current_stmt_binlog_format member

Update submodule, change the source file list
rename CACHE_LINE_SIZE in ut0counter, so it does not conflics with
rocksdb sources, which also defines this constant now.

simplify fix

field_ref_zero: make bigger

buf_is_zeroes(): remove a loop and check in one go

buf_is_zeroes(): stop assuming that argument buffer size
is always a multiply of 4096. And thus stop reading past
that buffer.

Making a linked list of dtuple_t is needed only for inserting
records. It's better to store tuples in a non-intrusive
container to not affect all other use cases of dtuple_t

dtuple_t::tuple_list: removed, it was 2 * sizeof(void*) bytes

ins_node_t::entry_list: now it's std::vector<dtuple_t*>

ins_node_t::entry: now it's std::vector<dtuple_t*>::iterator

DBUG_EXECUTE_IF("row_ins_skip_sec": this dead code removed

move span.h to a proper place to make it available for the whole server

Reformat it.

Constuctors from a contigous container are fixed
to use cont.data() instead of cont.begin()

span<>::index_type is replaced with span<>::size_type

In my micro-benchmarks memcmp(4196) 3 times faster than old
implementation. Also, it's generally better to use as less
reinterpret_casts<> as possible.

buf_is_zeroes(): renamed from buf_page_is_zeroes() and
argument changed to span<> for convenience.

st_::span<T>::const_iterator: fixed

page_zip-verify_checksum(): make argument byte* instead of void*

           prepared statement

The method Item_func_in::build_clone() that builds a clone item for an
Item_func_in item first calls a generic method Item_func::build_item()
that builds the the clones for the arguments of the Item_func_in item
to be cloned, creates a copy of the Item_func_in object and attaches the
clones for the arguments to this copy. Then the method Item_func_in::build_clone()
makes the copy fully independent on the copied object in order to
guarantee a proper destruction of the clone. The fact is the copy of the
Item_func_in object is registered as any other item object and should be
destructed as any other item object.
If the method Item_func::build_item fails to build a clone of an argument
then it returns 0. In this case no copy of the Item_func_in object should
be created. Otherwise the finalizing actions for this copy would not be
performed and the copy would remain in a state that would prevent its
proper destruction.

The code of Item_func_in::build_clone() before this patch created the copy
of the Item_func_in object before cloning the argument items. If this
cloning failed the server crashed when trying to destruct the copy item.

The code of Item_row::build_clone() was changed similarly to the code of
Item_func::build_clone though this code could not cause any problems.

Remove CREATE/DROP database.

Remove some unnecessary suppressions, replacements, and
SQL statements.

Populate tables via have_sequence.inc to avoid the creation of
explicit InnoDB record locks in INSERT...SELECT. This will remove
some gaps in AUTO_INCREMENT values.

After MDEV-12353, the consistency check that I originally added for
commit 1b9fe0bb
(InnoDB Plugin for MySQL 5.1) started randomly failing.

It turns out that the IMPORT TABLESPACE code was always incorrect:
it did not update the (redundantly stored) tablespace ID
in index tree root pages. It only does that for page headers
and BLOB pointers.

PageConverter::update_index_page(): Update the tablespace ID
in the BTR_SEG_TOP and BTR_SEG_LEAF of index root pages.

The problem happened in these line:

uval0= (ulonglong) (val0_negative ? -val0 : val0);
uval1= (ulonglong) (val1_negative ? -val1 : val1);

return check_integer_overflow(val0_negative ? -(longlong) res : res,
                              !val0_negative);

when unary minus was performed on -9223372036854775808.
This behavior is undefined in C/C++.

Several macros such as sint2korr() and uint4korr() are using the
arithmetic + operator while a bitwise or operator would suffice.

GCC 5 and clang 5 and later can detect patterns consisting of
bitwise or and shifts by multiples of 8 bits, such as those used
in the InnoDB function mach_read_from_4(). They actually translate
that verbose low-level code into high-level machine language
(i486 bswap instruction or fused into the Haswell movbe instruction).

We should do the same for MariaDB Server code that is outside InnoDB.

Note: The Microsoft C compiler is lacking this optimization.
There, we might consider using _byteswap_ushort(), _byteswap_ulong(),
_byteswap_uint64(). But, those would lead to unaligned reads, which are
bad for reasons stated in MDEV-20277. Besides, outside InnoDB,
most data is already being stored in the native little-endian format
of that compiler.

fil_delete_tablespace(): Remove the unused parameter drop_ahi,
and add the parameter if_exists=false. We want to suppress
error messages if we know that the tablespace has been discarded.

dict_table_rename_in_cache(): Pass the new parameter to
fil_delete_tablespace(), that is, do not complain about
missing tablespace if the tablespace has been discarded.

row_make_new_pathname(): Declare as static.

row_drop_table_for_mysql(): Tolerate !table->data_dir_path
when the tablespace has been discarded.

row_rename_table_for_mysql(): Skip part of the RENAME TABLE
when fil_space_get_first_path() returns NULL.

buf_pool_resize(): Simplify the fault injection
for innodb.buf_pool_resize_oom.

innodb.buf_pool_resize_oom: Use a small buffer pool.

innodb.innodb_buffer_pool_load_now: Make use of the sequence engine,
to avoid creating explicit InnoDB record locks. Clean up the
accesses to information_schema.innodb_buffer_page_lru.

Tests fixed.
MBR::Within() function fixed.

- This issue is caused by MDEV-19176
(bba59abb).
- Problem is that there is miscalculation of available memory during
recovery if innodb_buffer_pool_instances > 1.
- Ignore the buffer pool instance while calculating available_memory
- Removed recv_n_pool_free_frames variable and use buf_pool_get_n_pages()
instead.

Temporary tables are typically short-lived, and temporary tables
are assumed to be accessed only by the thread that is handling
the owning connection. Hence, they must not be subject to
defragmenting.

ha_innobase::optimize(): Do not add temporary tables to
the defragment_table() queue.

AUTO_INCREMENT values are nondeterministic after crash recovery.
While MDEV-6076 guarantees that the AUTO_INCREMENT values of committed
transactions will not roll back, it is possible that the AUTO_INCREMENT
values will be durably incremented for incomplete transactions. So
changing the test case to avoid showing the result of AUTO_INCREMENT value.

Error message now shows the whole value.

Rows_log_event::change_to_flashback_event(): Reduce the scope
of the variable swap_buff2, and do not duplicate conditions.

GCC 9.3.0 flagged the -Wmaybe-uninitialized when compiling the
10.5 branch using cmake -DWITH_ASAN=ON -DCMAKE_CXX_FLAGS=-O2

Function os_file_get_last_error_low returns error number +
OS_FILE_ERROR_MAX (which is currently set to 200) for unknown numbers to
this program.

to work better for CPUs with more than 2000 bogomips.
old behavior is preserved if less than 2500 bogomips.

see e.g. `add_to_status()`

myrg_open(): Reduce the scope of the variable 'end' and
simplify the code.

For some reason, I got no warning for this code in the 10.2
branch, only 10.3 or later.

The ENGINE=MERGE is covered by the tests main.merge, main.merge_debug,
and main.merge-big.

Problem:
=======
When we upgrade from "mysql" to "mariadb" if slave is using repositories as
tables their data is completely ignored and no warning is issued in error log.

Fix:
===
"mysql_upgrade" test should check for the presence of data in
"mysql.slave_master_info" and "mysql.slave_relay_log_info" tables. When tables
have some data the upgrade script should report a warning which hints users
that the data in repository tables will be ignored.

_ma_fetch_keypage(): Correct an assertion that used to always hold.
Thanks to clang -Wint-in-bool-context for flagging this.

double_to_datetime_with_warn(): Suppress -Wimplicit-int-float-conversion
by adding a cast. LONGLONG_MAX converted to double will actually be
LONGLONG_MAX+1.

All tablespace metadata is buffered in fil_system. There is a LRU
mechanism, but that only controls the opening and closing of
fil_node_t::handle.

It is much more efficient and less error-prone to access data file names
by looking up the fil_space_t object rather than by essentially joining
each row with an access to SYS_DATAFILES via the InnoDB internal SQL parser.

dict_get_first_path(): Declare static. The function may only be needed
when loading or updating the data dictionary. Also, change a condition
in order to avoid a bogus GCC 10 -Wstringop-overflow warning for
mem_strdupl() about len==ULINT_UNDEFINED.

i_s_sys_tablespaces_fill_table(): Do not access other InnoDB internal
dictionary tables than SYS_TABLESPACES.