btr_free_if_exists(): Always use the BUF_GET_POSSIBLY_FREED mode
when accessing pages, because due to MDEV-24589 the function
fil_space_t::set_stopping(true) can be called at any time during
the execution of this function.

mtr_t::m_freeing_tree: New data member for debugging purposes.

buf_page_get_low(): Assert that the BUF_GET mode is not being used
anywhere during the execution of btr_free_if_exists().

In all code related to freeing or allocating pages, we will add some
robustness, by making more use of BUF_GET_POSSIBLY_FREED and by
reporting an error instead of crashing in some cases of corruption.

fil_check_pending_ops(), fil_check_pending_io(): Remove.
These functions were actually duplicating each other ever since
commit 118e258a (MDEV-23855).

fil_space_t::check_pending_operations(): Replaces
fil_check_pending_operations() and incorporates the logic of
fil_check_pending_ops(). Avoid unnecessary lookups for the tablespace.
Just wait for the reference count to drop to zero.

fil_space_t::io(): Remove an unnecessary condition. We can (and
probably better should) refuse asynchronous reads of undo tablespaces
that are being truncated.

fil_truncate_prepare(): Remove.

trx_purge_truncate_history(): Implement the necessary steps that used
to be in fil_truncate_prepare().

MDEV-22265 Connect string character limit too small for full 64 character InnoDB table-name limit when using ad-hoc Spider server definitions.

Fix length for getting default table name.

In the SUX_LOCK_GENERIC implementation, we can remember at most
one pending exclusive lock request. If multiple exclusive lock
requests are pending, the WRITER_WAITING flag will be cleared when
the first waiting writer acquires the exclusive lock.

ssux_lock_low::update_lock(): If WRITER_WAITING is set, wake up
the writer even if the UPDATER flag is set, because the waiting
writer may be in the process of upgrading its U lock to X.

rw_lock::read_unlock(): Also indicate that an X lock waiter must
be woken up if an U lock exists.

This fix may cause unnecessary wake-ups and system calls, but this
is the best that we can do. Ideally we would use the MDEV-25404
idea of a separate 'writer' mutex, but there is no portable way to
request that a non-recursive mutex be created, and InnoDB requires
the ability to transfer buf_block_t::lock ownership to an I/O thread.

To allow problems like this to be caught more reliably in the future,
we add a unit test for srw_mutex, srw_lock, ssux_lock, sux_lock.

complemented the fix for MDEV-24823 in 10.2. As it is the only call of
this function in 10.3 the commit also has added the code of the function.

except commit 1288dfff

It is possible that an object that was originally created by
open_purge_table() will remain cached and reused for SQL execution.
Our previous fix wrongly assumed that ha_innobase::open() would
always be called before SQL execution starts. Therefore, we must
invoke dict_stats_init() in ha_innobase::info_low() instead of
only doing it in ha_innobase::open().

Note: Concurrent execution of dict_stats_init() on the same table
is possible, but it also was possible between two calls to
ha_innobase::open(), with no ill effects observed.

This should fix the assertion failure on stat_initialized.
A possibly easy way to reproduce it would have been
to run the server with innodb_force_recovery=2 (disable the purge of
history), update a table so that an indexed virtual column will be
affected, and finally restart the server normally (purge enabled),
to observe a crash when the table is accessed from SQL.

The problem was first observed and this fix verified by
Elena Stepanova. Also Thirunarayanan Balathandayuthapani
repeated the problem.

row_sel_sec_rec_is_for_clust_rec(): If the field in the
clustered index record stored off page, always fetch it,
also when the secondary index field has been built on the
entire column. This was broken ever since the InnoDB Plugin
for MySQL Server 5.1 introduced ROW_FORMAT=DYNAMIC and
ROW_FORMAT=COMPRESSED for InnoDB tables. That code was first
introduced in this tree in
commit 3945d5e5.

For the original ROW_FORMAT=REDUNDANT and the MySQL 5.0.3
ROW_FORMAT=COMPRESSED, there was no problem, because for
those tables we always stored at least a 768-byte prefix of
each column in the clustered index record.

row_sel_sec_rec_is_for_blob(): Allow prefix_len==0 for matching
the full column.

Before FRM is written walk vcol expressions through
check_table_name_processor() and check if field items match (db,
table_name) qualifier.

We cannot do this in check_vcol_func_processor() as there is already
no table name qualifiers in expressions of written and loaded FRM.

Buffer overflow in ib_push_warning() fixed by using vsnprintf().

InnoDB parser was obsoleted by MDEV-16417.

Thanks to Nikita Malyavin for review and suggestion.

It's Oracle libmysqlclient license exception, we no longer include,
build or ship libmysqlclient

row_ins_clust_index_entry_low(): Do not enable bulk insert if
any record locks exist on the table. Bulk insert is assumed to
be covered only by an exclusive table lock, with no row-level
locking or undo logging.

Remove garbage files.

Before this patch mergeable derived tables / view used in a multi-table
update / delete were merged before the preparation stage.
When the merge of a derived table / view is performed the on expression
attached to it is fixed and ANDed with the where condition of the select S
containing this derived table / view. It happens after the specification of
the derived table / view has been merged into S. If the ON expression refers
to a non existing field an error is reported and some other mergeable derived
tables / views remain unmerged. It's not a problem if the multi-table
update / delete statement is standalone. Yet if it is used in a stored
procedure the select with incompletely merged derived tables / views may
cause a problem for the second call of the procedure. This does not happen
for select queries using derived tables / views, because in this case their
specifications are merged after the preparation stage at which all ON
expressions are fixed.
This patch makes sure that merging of the derived tables / views used in a
multi-table update / delete statement is performed after the preparation
stage.

Approved by Oleksandr Byelkin <sanja@mariadb.com>

Before this patch mergeable derived tables / view used in a multi-table
update / delete were merged before the preparation stage.
When the merge of a derived table / view is performed the on expression
attached to it is fixed and ANDed with the where condition of the select S
containing this derived table / view. It happens after the specification of
the derived table / view has been merged into S. If the ON expression refers
to a non existing field an error is reported and some other mergeable derived
tables / views remain unmerged. It's not a problem if the multi-table
update / delete statement is standalone. Yet if it is used in a stored
procedure the select with incompletely merged derived tables / views may
cause a problem for the second call of the procedure. This does not happen
for select queries using derived tables / views, because in this case their
specifications are merged after the preparation stage at which all ON
expressions are fixed.
This patch makes sure that merging of the derived tables / views used in a
multi-table update / delete statement is performed after the preparation
stage.

Approved by Oleksandr Byelkin <sanja@mariadb.com>

* MSVC check was lost in a bad merge
* add a comment
* move AIX check where it belongs and where it would still
  allow -Werror, if desired

While MDEV-24589 causes the regression
MDEV-25491 Race condition between DROP TABLE and purge of
SYS_INDEXES record
we must not revert it from 10.6, because MDEV-24589 is a prerequisite for
MDEV-25180 Atomic ALTER TABLE
that is targeting 10.6. The regression will be dealt with later.

Fix is to changed message to be [WARNING] for backup

There is new Yukon Standard time Windows timezone.

Also fix the powershell script that generates the Windows locale mapping,
tell powershell to use TLSv1.2 to access the github (on some reason it is
TLS1.1 that powershell is using by default, and it does no work)

The U-to-X upgrade turned out to be incorrect. A debug assertion
failed in wr_wait(), called from mtr_defer_drop_ahi() in a stress
test with innodb_adaptive_hash_index=ON.

A correct upgrade procedure ought to be readers.fetch_add(WRITER-1)
to register ourselves as a WRITER (or waiting writer) and to release
the reference that was being held for the U lock.

Thanks to Matthias Leich for catching the problem.

This reverts commit e731a283.

A crash occurred during the test stress.ddl_innodb when
fil_delete_tablespace() for DROP TABLE was waiting in
fil_check_pending_operations() and a purge thread for handling
an earlier DROP INDEX was attempting to load the index root page
in btr_free_if_exists() and btr_free_root_check(). The function
buf_page_get_gen() would write out several times
"trying to read...being-dropped tablespace"
before giving up and committing suicide.

It turns out that during any page access in btr_free_if_exists(),
fil_space_t::set_stopping() could have been invoked by
fil_check_pending_operations(), as part of dropping the tablespace.
Preventing this race condition would require extensive changes
to the allocation code or some locking mechanism that would ensure
that we only set the flag if btr_free_if_exists() is not in progress.

Either way, that could be a too risky change in a GA release.
Because MDEV-24589 is not strictly necessary in the 10.5 release
series and it only is a requirement for MDEV-25180 in a later
major release, we will revert the change from 10.5.

Issue:- Since there is no waiting for the actual disconnection of the con_tmp
(which does XA prepare of test1), We can have a issue when test1 is not
prepared and we are calling rollback on test1 , giving XAER_NOTA: Unknown XID
error

Solution:- Wait for the complete disconnection of con_tmp

buf_resize_callback(): Correct an invalid assertion, and enable
the assertion in debug builds only.

Between buf_resize_start() and buf_resize_shutdown(),
srv_shutdown_state must be less than SRV_SHUTDOWN_CLEANUP.

The incorrect assertion had been introduced in
commit 5e62b6a5 (MDEV-16264).
As a result, the server could crash if shutdown was initiated
concurrently with initiating a change of innodb_buffer_pool_size.

		to mysql interpreter

InnoDB returns uninitialized statistics to mysql interpreter
when background thread is opening the table. So it leads to
assertion failure. In that case, InnoDB avoid sending
innodb statistics information to mysql interpreter.

node->index was NULL.
But it's possible to get dict_table_t* from another source.

There was race between a committing transaction and the following in binlog
order FLUSH LOGS that could create a 2nd Binlog checkpoint (BCP) event
in the new file *before* the first logged-in-old-binlog transaction gets committed in
Innodb. That would cause the transaction loss at recovery, should
the server stop right after the BCP.

The race is tackled by enforcing the necessary set of mutexes to be acquired
by FLUSH-LOGS handler in the correct order (of the group commit leader
pattern).

Note, there remain two cases where a similar race is still possible:
  - the above race as it is when the server is run with ("unlikely")
    non-default `--binlog-optimize-thread-scheduling=0` (MDEV-24530), and
  - at unlikely event of bin-logging of Incident event (MDEV-24531) that
    also triggers binlog rotation,
    in both cases though with lesser chances after the current fixes.