log_t::has_encryption_key_rotation(): checks whether
key rotation is supported.

In a subsequent redo log format version, this key rotation
may be broken again.

Write log header just ones when file is created, instead of
writing to it on every log file wrap around.

log_t::file::write_header_durable(): this one writes to log header

log_write_buf(): this one stops writing to log header

move statistics modification into one place

restore check for client charset_info == NULL, which was previously
removed in MDEV-8844

that by a (un)lucky coincidence did not prevent 8fd654ce
from working properly

when selecting from perfschema, filter out statements
used by the test istself in wait_condition.inc, because they,
by design, can be repeated unpredictable number of times.

By default, when redo log is being written for modifying a persistent
data page, the data page must actually be changed. If the write can
sometimes be optimized away, then the template parameter w=mtr_t::OPT
should be passed in order to silence the debug assertion failure.

InnoDB undo log pages can be reused without properly freeing or
initializing them in between. In particular, the undo log header
page field TRX_UNDO_TRX_NO could have been part of an undo log
record page, and those bytes could accidentally have the desired
value when the page is reused as an undo log header page of
another transaction.

Because the function trx_undo_set_state_at_finish() always changes
the TRX_UNDO_STATE of the page, and because recovery is only reading
TRX_UNDO_TRX_NO for pages that either have the correct TRX_UNDO_STATE
or, in trx_rseg_array_init(), are attached to the TRX_SYS page, the
garbage values in TRX_UNDO_TRX_NO do not seem to cause a problem.

This assertion failure affects debug builds only.

Force correct PCRE2 linking in the official binaries.
System pcre2 in RPM/DEB, bundled in bintars.

fix build requirements for debian

strip all client binaries (that is, not mysqld) in bintars

in mysql_release builds only build embedded for rpm and deb
but not for bintar

e.g.
- dont -> don't
- occurence -> occurrence
- succesfully -> successfully
- easyly -> easily

Also remove trailing space in selected files.

These changes span:
- server core
- Connect and Innobase storage engine code
- OQgraph, Sphinx and TokuDB storage engines

Related to MDEV-21769.

Instrument new synchronization primitive with thd_wait_begin/end
to inform threadpool about waits.

This considerably improve performance on write benchmarks
(e.g sysbench update_index) with generic threadpool, of course the cost is
possibility of many newly created threads.

Addon fields will be packed if the length of addon fields is greater
than max_length_for_sort_data.

Fixed XA-ROLLBACK not to write into binlog when XA-prepare run
in sql_log_bin-OFF environment. (Two tests affected).

Part of
MDEV-742 - XA PREPAREd transaction survive disconnect/server restart

Lifted long standing limitation to the XA of rolling it back at the
transaction's
connection close even if the XA is prepared.

Prepared XA-transaction is made to sustain connection close or server
restart.
The patch consists of

    - binary logging extension to write prepared XA part of
      transaction signified with
      its XID in a new XA_prepare_log_event. The concusion part -
      with Commit or Rollback decision - is logged separately as
      Query_log_event.
      That is in the binlog the XA consists of two separate group of
      events.

      That makes the whole XA possibly interweaving in binlog with
      other XA:s or regular transaction but with no harm to
      replication and data consistency.

      Gtid_log_event receives two more flags to identify which of the
      two XA phases of the transaction it represents. With either flag
      set also XID info is added to the event.

      When binlog is ON on the server XID::formatID is
      constrained to 4 bytes.

    - engines are made aware of the server policy to keep up user
      prepared XA:s so they (Innodb, rocksdb) don't roll them back
      anymore at their disconnect methods.

    - slave applier is refined to cope with two phase logged XA:s
      including parallel modes of execution.

This patch does not address crash-safe logging of the new events which
is being addressed by MDEV-21469.

CORNER CASES: read-only, pure myisam, binlog-*, @@skip_log_bin, etc

Are addressed along the following policies.
1. The read-only at reconnect marks XID to fail for future
   completion with ER_XA_RBROLLBACK.

2. binlog-* filtered XA when it changes engine data is regarded as
   loggable even when nothing got cached for binlog.  An empty
   XA-prepare group is recorded. Consequent Commit-or-Rollback
   succeeds in the Engine(s) as well as recorded into binlog.

3. The same applies to the non-transactional engine XA.

4. @@skip_log_bin=OFF does not record anything at XA-prepare
   (obviously), but the completion event is recorded into binlog to
   admit inconsistency with slave.

The following actions are taken by the patch.

At XA-prepare:
   when empty binlog cache - don't do anything to binlog if RO,
   otherwise write empty XA_prepare (assert(binlog-filter case)).

At Disconnect:
   when Prepared && RO (=> no binlogging was done)
     set Xid_cache_element::error := ER_XA_RBROLLBACK
     *keep* XID in the cache, and rollback the transaction.

At XA-"complete":
   Discover the error, if any don't binlog the "complete",
   return the error to the user.

Kudos
-----
Alexey Botchkov took to drive this work initially.
Sergei Golubchik, Sergei Petrunja, Marko Mäkelä provided a number of
good recommendations.
Sergei Voitovich made a magnificent review and improvements to the code.
They all deserve a bunch of thanks for making this work done!

revert e74c1c9e to restore 2bbcf9a1

also remove redundant --connection commands

mariabackup tries to allocate a buffer of page_size*page_size/4 size.
for 64k page it means 1Gb, which doesn't work very well on 32-bit builders.

Skip the 64k page test on 32bit.

this fixes main.mysqld--defaults-file failure with --mem

1. Refactored innobase_close_connection(). Transaction must've already
been rolled back by this time. We should expect only transactions in the
PREPARED state when MDEV-742 is done.

2. Added missing put_pins() to trx_disconnect_prepared(). Missing
put_pins() wasn't a problem because trx_disconnect_prepared() is a dead
code. But it will get revived in the main MDEV-742 patch.

3. Fixed missing reset of trx->mysql_log_file_name when RW transaction
didn't emit any log records (zero-modification RW). The problem was
detected by ASAN when disconnected XA transaction was trying to make
use of inherited mysql_log_file_name pointing into binlog data of
detached THD.

This missing reset also had user-visible side effect, when
trx_sys_print_mysql_binlog_offset() would report binlog position
not of the most recently committed transaction.

One of possible scenarios that is expected to misbehave is as following:

  thr1> CREATE TABLE t1(a INT) ENGINE=InnoDB;
  thr1> INSERT INTO t1 VALUES(1);
  thr1> BEGIN;
  thr1> UPDATE t1 SET a=1
  thr1> COMMIT; -- zero-modification, misses to reset mysql_log_file_name

  thr2> BEGIN;
  thr2> INSERT INTO t1 VALUES(2);
  thr2> COMMIT;

  thr1> BEGIN;
  thr1> do-some-real-changes;
  thr1> ROLLBACK; -- will store binlog pos from previous COMMIT in thr1?

In this case it means if binlog is replayed from position reported by
trx_sys_print_mysql_binlog_offset(), t1 will end up with two records
containing '2'.

Part of
MDEV-742 - XA PREPAREd transaction survive disconnect/server restart

It now lives from THD constructor to THD destructor. Reset before THD is
released to a cache. Change user doesn't reset debug_sync_control anymore.

Needed to be able to make use of DEBUG_SYNC() at later stages like
ha_close_connection().

- This issue was caused by 5e62b6a5.
fts_optimize_callback() should free fts_optimize_wq and make it as NULL
when it receives FTS_MSG_STOP message. So that subsequent
fts_optimize_callback() doesn't fail with segmentation fault.

Starting with commit 1a6f708e
the function buf_pool_get_dirty_pages_count() is only used
in a debug check. It was dead code for non-debug builds.

buf_flush_dirty_pages(): Perform the debug check inline,
and replace the assertion
	ut_ad(first || buf_pool_get_dirty_pages_count(id) == 0);
with another one that is executed while holding the mutexes:
	ut_ad(id != bpage->id.space());

Updating libmariadb to use 3be5897c3346639fa6d7195480d93108798c4917,
which fixed the problem.

Create_tmp_table::add_fields(): Initialize uneven_delta= 0
to suppress the warning from GCC 9.2.1 and 10.0.1,
and consistently indent the code with spaces.

Fix or disable those -Wconversion that were missed by GCC 5.4.0
targeting AMD64.

The -Wconversion in GCC seems to be stricter than in clang.
GCC at least since version 4.4.7 issues truncation warnings for
assignments to bitfields, while clang 10 appears to only issue
warnings when the sizes in bytes rounded to the nearest integer
powers of 2 are different.

Before GCC 10.0.0, -Wconversion required more casts and would not
allow some operations, such as x<<=1 or x+=1 on a data type that
is narrower than int.

GCC 5 (but not GCC 4, GCC 6, or any later version) is complaining
about x|=y even when x and y are compatible types that are narrower
than int.  Hence, we must rewrite some x|=y as
x=static_cast<byte>(x|y) or similar, or we must disable -Wconversion.

In GCC 6 and later, the warning for assigning wider to bitfields
that are narrower than 8, 16, or 32 bits can be suppressed by
applying a bitwise & with the exact bitmask of the bitfield.
For older GCC, we must disable -Wconversion for GCC 4 or 5 in such
cases.

The bitwise negation operator appears to promote short integers
to a wider type, and hence we must add explicit truncation casts
around them. Microsoft Visual C does not allow a static_cast to
truncate a constant, such as static_cast<byte>(1) truncating int.
Hence, we will use the constructor-style cast byte(~1) for such cases.

This has been tested at least with GCC 4.8.5, 5.4.0, 7.4.0, 9.2.1, 10.0.0,
clang 9.0.1, 10.0.0, and MSVC 14.22.27905 (Microsoft Visual Studio 2019)
on 64-bit and 32-bit targets (IA-32, AMD64, POWER 8, POWER 9, ARMv8).