Less error prone, stricter type control.

This couldn't cause any bugs as ptr was zero terminated, but still better
to have the length correct.

This change also affects information_schema.tables

The create table option "transactional=0 | 1" is now always shown for
storage engines that supports both transactional/crash safe tables and
non transactional tables.

Before this patch the transactional=... option was only shown if the user
specified transactional=... in the CREATE TABLE or ALTER TABLE statement.
The reason for the change was to be able to make it easy to know if an Aria
table is transactional or not.

A crash was observed where dict_acquire_mdl_shared<trylock=false>
would invoke memcpy() with an apparently uninitialized tbl_len.

dict_table_t::parse_name(): Remove an unnecessary tbl_len--
operation. (This should be mostly non-functional cleanup.)

dict_acquire_mdl_shared(): If the second dict_table_t::parse_name()
returns false, terminate the loop just like we would do on the
first invocation.

MDEV-22746: Assertion `(&(&pagecache->cache_lock)->m_mutex)->count > 0 && pthread_equal(pthread_self(), (&(&pagecache->cache_lock)->m_mutex)->thread)' failed in dec_counter_for_resize_op

Removed second attempt to decrease counter

commit d09aec7a (MDEV-19940)
caused a regression. We made wait_lock_get_heap_no() return
uint16_t instead of ulint, and we mostly replaced the previous
magic value ULINT_UNDEFINED with 0. But, we failed to adjust
some assertions. Furthermore, 0 is a valid although rare value
for record locks. (Record locks can be temporarily stored on
page infimum in some operations that involve multiple leaf pages.)

Let us use 0xFFFF as the magic value. Valid heap numbers
are limited to less than 9362 = innodb_page_size/(5+1+1)
when using a minimal 1-byte PRIMARY KEY and a
secondary index on a NULL or '' column.

Wrong condition for corner values.

The constructor of Lex_ident_sys returns LEX_CSTRING(NULL,0) if character set
conversion goes wrong, and raises the "wrong character string" error in
the diagnostics area.

The code in sql_yacc.yy did not check Lex_ident_sys::ptr against NULL,
so the execution entered functions that did not expect NULL (and crashed).

Fixing the code to do MYSQL_YYABORT if Lex_ident_sys::ptr is NULL
after constructing.

commit 3a37644a added a non-POD
member buf_page_info_t::id, and thus GCC 7 or later would complain
about a memset() call. Let my_malloc fill the memory for us.

InnoDB mutex monitor is accessing mutexes of poisoned (cached) trx
objects. Unpoison ReadView::m_mutex similarly to trx_t::mutex.

This is regression after MDEV-22593.

- Remove extra ',' and quotes
- Remove extra newline and remove double newlines
- Added options --lsn-redo-end and --lsn-undo-end to aria_read_log
- Allow one to give the aria_read_log lsn aruments as number,0xhexnumber,
  the same way as lsn's are written by aria_read_log
- Don't write full pages to redo log with EXTRA_DEBUG as this takes up
  a lot of disk and there has not been a need for this extra loggging for
  a long time. Instead one should use EXTRA_ARIA_DEBUG instead.

commit 8ccb3caa micro-optimized
page_id_t as a wrapper of uint64_t.

buf_dump_t: Remove, and replace with page_id_t, which uses
exactly the same encoding.

buf_page_info_t: Replace space_id,page_num with page_id_t id.

i_s_innodb_set_page_type(): Remove unnecessary code.
The buf_page_info_t::id was already assigned at the start
of the only caller, i_s_innodb_buffer_page_get_info().

trx->no is duplicated by trx->rw_trx_hash_element->no for no good reason.
The latter is preferred for performance reasons: allows to avoid taking
trx->rw_trx_hash_element->mutex when snapshotting.

This was the last abuse of trx_sys.mutex, which is now exclusively
protecting trx_sys.trx_list.

This global acquisition was also potential scalability bottleneck for
oltp_read_write benchmark. Although it didn't expose itself as such due
to larger scalability issues.

Replaced trx_sys.mutex based synchronisation between ReadView creator
thread and purge coordinator thread performing latest view clone with
ReadView::m_mutex.

It also allowed to simplify tri-state view m_state down to boolean
m_open flag.

For performance reasons trx->read_view.close() is left as atomic relaxed
store, so that we don't have to waste resources for otherwise meaningless
mutex acquisition.

MDEV-22696 TP_pool_generic::set_pool_size logic so that it marks each connection to change group before the next socket read.

MDEV-22696 Threadpool : make sure thd->event_scheduler.data does not change as long as THD is in server_threads.

Calling stmt rollback closed the transaction, which caused the above issue

Updated the corresponding rdiff file

The failure was:
mysqltest: At line 1737: query 'reap' failed: 1397: XAER_NOTA: Unknown XID

The bug was in the test case int that it executed REAP XA COMMIT before
the connection had truly disconnected

The bug was that sometimes one get check errors like:
-AUTO_INCREMENT_OFFSET  4
+AUTO_INCREMENT_OFFSET  3

MDEV-22617 Galera node crashes when trying to log to slow_log table in
streaming replication mode

Other things:
- Changed name of wsrep_after_row(two arguments) to
  wsrep_after_row_internal(one argument) to not depended on the
  function signature with unused arguments.

When my_vsnprintf() is patched, the code protected disabled with
'WAITING_FOR_BUGFIX_TO_VSPRINTF' should be enabled again. Also all %b
formats in this patch should be revert to %s again

Now this InnoDB message is printed after one second of stalled operations
and then every 10 seconds

MDEV-22531 Remove maria::implicit_commit()
MDEV-22607 Assertion `ha_info->ht() != binlog_hton' failed in
           MYSQL_BIN_LOG::unlog_xa_prepare

From the handler point of view, Aria now looks like a transactional
engine. One effect of this is that we don't need to call
maria::implicit_commit() anymore.

This change also forces the server to call trans_commit_stmt() after doing
any read or writes to system tables.  This work will also make it easier
to later allow users to have system tables in other engines than Aria.

To handle the case that Aria doesn't support rollback, a new
handlerton flag, HTON_NO_ROLLBACK, was added to engines that has
transactions without rollback (for the moment only binlog and Aria).

Other things
- Moved freeing of MARIA_SHARE to a separate function as the MARIA_SHARE
  can be still part of a transaction even if the table has closed.
- Changed Aria checkpoint to use the new MARIA_SHARE free function. This
  fixes a possible memory leak when using S3 tables
- Changed testing of binlog_hton to instead test for HTON_NO_ROLLBACK
- Removed checking of has_transaction_manager() in handler.cc as we can
  assume that as the transaction was started by the engine, it does
  support transactions.
- Added new class 'start_new_trans' that can be used to start indepdendent
  sub transactions, for example while reading mysql.proc, using help or
  status tables etc.
- open_system_tables...() and open_proc_table_for_Read() doesn't anymore
  take a Open_tables_backup list. This is now handled by 'start_new_trans'.
- Split thd::has_transactions() to thd::has_transactions() and
  thd::has_transactions_and_rollback()
- Added handlerton code to free cached transactions objects.
  Needed by InnoDB.

squash! 2ed35999f2a2d84f1c786a21ade5db716b6f1bbc

All changes (except one) is of type
thd->transaction.  -> thd->transaction->

thd->transaction points by default to 'thd->default_transaction'
This allows us to 'easily' have multiple active transactions for a
THD object, like when reading data from the mysql.proc table

MDEV-22468 BACKUP STAGE BLOCK_COMMIT should block commit in the Aria engine

This is needed to ensure that mariabackup works properly with Aria tables

This code ads new calls to ha_maria::implicit_commit(). These will be
deleted by MDEV-22531 Remove maria::implicit_commit().

This patch is also pushed in 10.4. It's pushed separately in 10.5 as there
are some additional cases in 10.5 to take care of.

When merging if there is conflicts, use this code, not the 10.4 code.

- Don't use 'auto' to declare variables (lazy and makes code harder to read)
- Fixed length to use correct type