MariaDB 11.1.3 release

In case of a non-recovery XA rollback/commit in the same connection,
thon->rollback is called instead of rollback_by_xid, Though previously,
thd_ha_data was moved to thd->transaction->xid_state.xid in hton->prepare.

Like it wasn't enough, XA PREPARE can be skipped upon user and thus we
can end up in hton->commit/rollback with and unprepared XA, so checking
xid_state.is_explicit_XA is not enough -- we should check
xid_state.get_state_code() == XA_PREPARED, which will also guarantee
is_explicit_XA() == true.

Checking for kill with thd_kill_level() or check_killed() runs apc
requests, which takes the LOCK_thd_kill mutex. But this is dangerous,
as checking for kill needs to be called while holding many different
mutexes, and can lead to cyclic mutex dependency and deadlock.

But running apc is only "best effort", so skip running the apc if the
LOCK_thd_kill is not available. The apc will then be run on next check
of kill signal.
Signed-off-by: Kristian Nielsen <knielsen@knielsen-hq.org>

recv_dblwr_t::find_page(): Tablespace flags validity should be
checked only for page 0.

Correctly supress error issuing when saving value in field for comporison

Fix the issue introduced in ec2574fd, fix for MDEV-31983:

get_quick_record_count() must set quick_count=0 when it got
IMPOSSIBLE_RANGE from test_quick_select.

Failure to do so will cause an assertion in 11.0, when the number of
quick select rows (0) is checked to be lower than the number of
found_records (which is capped up to 1).

specify algorithm/lock explicitly, don't depend on server settings

recv_dblwr_t::find_page(): Tablespace flags validity should be
checked only for page 0.

fil_space_t::drop(): If the caller is not interested in a
detached handle, close it immediately.

XA support for online alter was totally missing.

Tying on binlog_hton made this hardly visible: simply having binlog_commit
called from xa_commit made an impression that it will automagically work
for online alter, which turns out wrong: all binlog does is writes
"XA END" into trx cache and flushes it to a real binlog.

In comparison, online alter can't do the same, since online replication
happens in a single transaction.

Solution: make a dedicated XA support.
* Extend struct xid_t with a pointer to Online_alter_cache_list
* On prepare: move online alter cache from THD::ha_data to XID passed
* On XA commit/rollback: use the online alter cache stored in this XID.
  This makes us pass xid_cache_element->xid to xa_commit/xa_rollback
  instead of lex->xid
* Use manual memory management for online alter cache list, instead of
  mem_root allocation, since we don't have mem_root connected to the XA
  transaction.

Use standard handlerton functions for savepoint add/rollback.

To identify the savepoint, the pointer passed is used.

Every table that has online alter in progress maintains a list of
savepoints independently.

Also this removes setting a value to a global variable savepoint_alloc_size
without any protection, which was a race condition bug.

Move all the functions dedicated to online alter to a newly created
online_alter.cc.

With that, make many functions static and simplify the static functions
naming.

Also, rename binlog_log_row_online_alter -> online_alter_log_row.

Assertion `!writer.checksum_len || writer.remains == 0' fails upon
concurrent online ALTER and transactions with failing statements and binary
log enabled.
Also another assertion, `pos != (~(my_off_t) 0)', fails in my_seek, upon
reinit_io_cache, on a simplified test. This means that IO_CACHE wasn't
properly initialized, or had an error before.

The overall problem is a deep interference with the effect of an installed
binlog_hton: the assumption about that thd->binlog_get_cache_mngr() is,
sufficiently, NULL, when we shouldn't run the binlog part of
binlog_commit/binlog_rollback, is wrong: as turns out, sometimes the binlog
handlerton can be not installed in current thd, but binlog_commit can be
called on behalf of binlog, as in the bug reported.

One separate condition found is XA recovery of the orphaned transaction,
when binlog_commit is also called, but it has nothing to do with
online alter.

Solution:
Extract online alter operations into a separate handlerton.

1032 (Can't find record) could be emitted when ALTER TABLE is execued vs
concurrent DELETE/UPDATE/other DML that would require search on the online
ALTER's side.

Innodb's INPLACE, in comparison, creates a new trx_t and uses it in scope
of the alter table context.

ALTER TABLE class of statements (i.g. CREATE INDEX, OPTIMIZE, etc.) is
expected to be unaffected by the value of current session's transaction
isolation.

This patch save-and-restores thd->tx_isolation and sets in to
ISO_REPEATABLE_READ for almost a whole mysql_alter_table duration, to avoid
any possible side-effect of it. This should be primarily done before the
lock_tables call, to initialize the storage engine's local value correctly
during the store_lock() call.

sql_table.cc: set thd->tx_isolation to ISO_REPEATABLE_READ in
mysql_alter_table and then restore it to the original value in the end of
the call.

data from a table similar to other JSON functions

Analysis:
Since we are fetching values for every row ( because we are running SELECT
for all rows of a table ), correct value can be only obtained at the time of
calling val_int() because it is called to get value for each row.
Fix:
Set up hash for each row instead of doing it during fixing fields.

The reason was that Event e11 was re-executed before
"ALTER EVENT e11 DISABLE" had been executed.

Fixed by increasing re-schedule time

Other things:
- Removed double accounting of 'execution_count'. It was incremented in
  top->mark_last_executed(thd) that was executed a few lines earlier.

Pushing down statements to FederatedX engine is implemented by
printing either SELECT_LEX or SELECT_LEX_UNIT into a string and
sending that string to the engine. In the case of pushing down a
single SELECT having a CTE (WITH clause) there was a problem, because
normally single SELECTs were printed using SELECT_LEX::print().
But CTEs are stored in the upper unit of the SELECT_LEX -
SELECT_LEX_UNIT, so they were not unfolded in the string produced.

The solution is to invoke SELECT_LEX_UNIT::print() when pushing down
single SELECT statements (but not those which are parts of units),
so the possible CTEs are unfolded and printed.

Reviewed by Sergei Petrunia (sergey@mariadb.com)

MDEV-32441 SENT_ROWS shows random wrong values when stored function
           is selected.
MDEV-32281 EXAMINED_ROWS is not populated in
           information_schema.processlist upon SELECT.

Added ROWS_SENT to information_schema.processlist
This is to have the same information as Percona server (SENT_ROWS)

To ensure that information_schema.processlist has correct values for
sent_rows and examined_rows I introduced two new variables to hold the
total counts so far. This was needed as stored functions and stored
procedures will reset the normal counters to be able to count rows for
each statement individually for slow query log.

Other things:
- Selects with functions shows in processlist the total examined_rows
  and sent_rows by the main statement and all functions.
- Stored procedures shows in processlist examined_rows and sent_rows
  per stored procedure statement.
- Fixed some double accounting for sent_rows and examined_rows.
- HANDLER operations now also supports send_rows and examined_rows.
- Display sizes for MEMORY_USED, MAX_MEMORY_USED, EXAMINED_ROWS and
  QUERY_ID in information_schema.processlist changed to 10 characters.
- EXAMINED_ROWS and SENT_ROWS changed to bigint.
- INSERT RETURNING and DELETE RETURNING now updates SENT_ROWS.
- As thd is always up to date with examined_rows, we do not need
  to handle examined row counting for unions or filesort.
- I renamed SORT_INFO::examined_rows to m_examined_rows to ensure that
  we don't get bugs in merges that tries to use examined_rows.
- Removed calls of type "thd->set_examined_row_count(0)" as they are
  not needed anymore.
- Removed JOIN::join_examined_rows
- Removed not used functions:
  THD::set_examined_row_count()
- Made inline some functions that where called for each row.

fil_delete_tablespace(): Invoke fil_space_free_low() directly.
This fixes up commit 39e3ca8b

Added missing initializer

According to the standart draft UUIDv6 and UUIDv7 values
must be compared as opaque raw bytes.

Let's only compare with byte-swapping if both values need
byte swapping.

* modify the test to use different and not monotonous timestamps
* rename methods to be unambiguous (for IDE challenged devs)
* move byte swap checks into helpers

Fixup for MDEV-31983, incorrect test for checking ability to use quick select.

Approved by Sergei Petrunia