The replacement of buf_pool.page_hash with a different type of
hash table in commit 5155a300 (MDEV-22871)
introduced a race condition with buffer pool resizing.

We have an execution trace where buf_pool.page_hash.array is changed
to point to something else while page_hash_latch::read_lock() is
executing. The same should also affect page_hash_latch::write_lock().

We fix the race condition by never resizing (and reallocating) the
buf_pool.page_hash. We assume that resizing the buffer pool is
a rare operation. Yes, there might be a performance regression if a
server is first started up with a tiny buffer pool, which is later
enlarged. In that case, the tiny buf_pool.page_hash.array could cause
increased use of the hash bucket lists. That problem can be worked
around by initially starting up the server with a larger buffer pool
and then shrinking that, until changing to a larger size again.

buf_pool_t::resize_hash(): Remove.

buf_pool_t::page_hash_table::lock(): Do not attempt to deal with
hash table resizing. If we really wanted that in a safe manner,
we would probably have to introduce a global rw-lock around the
operation, or at the very least, poll buf_pool.resizing, both of
which would be detrimental to performance.

MDEV-23004 When using GROUP BY with JSON_ARRAYAGG with joint table, the square brackets are not included

make test results stable

followup for 98c7916f

In other ROW_FORMAT than REDUNDANT, the InnoDB record header
size calculation depends on dict_index_t::n_core_null_bytes.

In ROW_FORMAT=REDUNDANT, the record header always is 6 bytes
plus n_fields or 2*n_fields bytes, depending on the maximum
record size. But, during online ALTER TABLE, the log records
in the temporary file always use a format similar to
ROW_FORMAT=DYNAMIC, even omitting the 5-byte fixed-length part
of the header.

While creating a temporary file record for a ROW_FORMAT=REDUNDANT
table, InnoDB must refer to dict_index_t::n_nullable.
The field dict_index_t::n_core_null_bytes is only valid for
other than ROW_FORMAT=REDUNDANT tables.

The bug does not affect MariaDB 10.3, because only
commit 7a27db77 (MDEV-15563)
allowed an ALGORITHM=INSTANT change of a NOT NULL column to
NULL in a ROW_FORMAT=REDUNDANT table.

The fix was developed by Thirunarayanan Balathandayuthapani
and tested by Matthias Leich. The test case was simplified by me.

One more result was affected by merging
768c5188.

This is a backport of 161e4bfa.

trans_rollback_to_savepoint(): Only release metadata locks (MDL)
if the storage engines agree, after the changes were already rolled back.

Ever since commit 3792693f
and mysql/mysql-server@55ceedbc3feb911505dcba6cee8080d55ce86dda
we used to cheat here and always release MDL if the binlog is disabled.

MDL are supposed to prevent race conditions between DML and DDL also
when no replication is in use. MDL are supposed to be a superset of
InnoDB table locks: InnoDB table lock may only exist if the thread
also holds MDL on the table name.

In the included test case, ROLLBACK TO SAVEPOINT would wrongly release
the MDL on both tables and let ALTER TABLE proceed, even though the DML
transaction is actually holding locks on the table.

Until commit 1bd681c8 (MDEV-25506)
in MariaDB 10.6, InnoDB would often work around the locking violation
in a blatantly non-ACID way: If locks exist on a table that is being
dropped (in this case, actually a partition of a table that is being
rebuilt by ALTER TABLE), InnoDB could move the table (or partition)
into a queue, to be dropped after the locks and references had been
released. If the lock is not released and the original copy of the
table not dropped quickly enough, a name conflict could occur on
a subsequent ALTER TABLE.

The scenario of commit 3792693f
is unaffected by this fix, because mysqldump
would use non-locking reads, and the transaction would not be holding
any InnoDB locks during the execution of ROLLBACK TO SAVEPOINT.
MVCC reads inside InnoDB are only covered by MDL and page latches,
not by any table or record locks.

FIXME: It would be nice if storage engines were specifically asked
which MDL can be released, instead of only offering a choice
between all or nothing. InnoDB should be able to release any
locks for tables that are no longer in trx_t::mod_tables, except
if another transaction had converted some implicit record locks
to explicit ones, before the ROLLBACK TO SAVEPOINT had been completed.

Reviewed by: Sergei Golubchik

Fixup for commit 768c5188

A table rebuild that would truncate the default value of a
DATE column is expected to issue data truncation warnings.
But, these warnings are not being issued if the ADD COLUMN
is being executed with ALGORITHM=INSTANT. InnoDB sets the
warning of the field while assigning the default value
of the field during check_if_supported_inplace_alter().

The error loading the client module is different

Parital backport of 48938c57
so platform dependent AIX tests can be done.

C:\projects\server\sql\sql_show.cc(7913): error C2220: warning treated as error - no 'object' file generated [C:\projects\server\win_build\sql\sql.vcxproj]
C:\projects\server\sql\sql_show.cc(7913): warning C4267: 'initializing': conversion from 'size_t' to 'uint', possible loss of data [C:\projects\server\win_build\sql\sql.vcxproj]

caused by 768c5188

Parital backport of 48938c57
so platform dependent AIX tests can be done.

Post-merge fix in 10.4: add a testcase for pushdown into IN subquery

Consider a query of the form:

  select ... from (select item2 as COL1) as T where COL1=123

Condition pushdown into derived table will try to push "COL1=123" condition
down into table T.
The process of pushdown involves "substituting" the item, that is,
replacing Item_field("T.COL1") with its "producing item" item2.
In order to use item2, one needs to clone it (call Item::build_clone).

If the item is not cloneable (e.g. Item_func_sp is not), the pushdown
process will fail and nothing at all will be pushed.

Fixed by introducing transform_condition_or_part() which will try to apply
the transformation for as many parts of condition as possible. The parts of
condition that couldn't be transformed are dropped.

Call to wsrep_sst_auth_free() was missing from normal shutdown.

Add KEYWORDS table and SQL_FUNCTIONS table to INFORMATION_SCHEMA.
This commits needs some minor changes when propagated upwards
(e.g. func_array in item_create.cc has a termination element that
 doesn't exist in later versions of MariaDB)

my_init_atomic_write(): Detect all forms of SSD, in case multiple
types of devices are installed in the same machine.
This was broken in commit ed008a74
and further in commit 70684afe.

SAME_DEV(): Match block devices, ignoring partition numbers.

Let us use stat() instead of lstat(), in case someone has a symbolic
link in /dev.

Instead of reporting errors with perror(), let us use fprintf(stderr)
with the file name, the impact of the error, and the strerror(errno).
Because this code is specific to Linux, we may depend on the
GNU libc/uClibc/musl extension %m for strerror(errno).

os_file_set_size(): Trim the current size down to the file system
block size, to obey the constraints for unbuffered I/O.

Fixed typo in variable name that breaks SST in some scenatios.

Also fixed one small inaccuracy after MDEV-25978 which leads
to the use of an uninitialized variable when the --log-bin
option is specified without an argument.

Handle invalid GEOJSON-s in Geometry::create_from_json().

square brackets are not included.

Item_func_json_arrayagg::copy_or_same() should be implemented.

buf_flush_relocate_on_flush_list(): If we are removing the block from
buf_pool.flush_list, subtract its size from buf_pool.stat.flush_list_bytes.
This fixes a regression that was introduced in
commit 22b62eda (MDEV-25113).