Part #2, specifically for the 10.5+ branch:

The auto-increment parameters can change sporadically during the
execution of the mtr test "galera_vote_rejoin_ddl", causing it to
fail. This patch creates an environment where unpredictable changes
to these auto-increment settings do not occur during the test.

also add =WARN as an alias for =OFF
and clarify the help text

In commit d25f806d (MDEV-22749)
the CRC-32C implementation of MariaDB was broken on some
IA-32 and AMD64 builds, depending on the compiler version and
build options. This was verified for IA-32 on GCC 10.2.1.

Even though we try to identify the SSE4.2 extensions and the
availaibility of the PCLMULQDQ instruction by executing CPUID,
the fall-back code could be generated with extended instructions,
because the entire file mysys/crc32/crc32c.c was being compiled
with -msse4.2 -mpclmul. This would cause SIGILL on a PINSRD
instruction on affected IA-32 targets (such as some Intel Atom
processors). This might also affect old AMD64 processors
(predating the 2007 Intel Nehalem microarchitecture), if some
compiler chose to emit the offending instructions.

While it is fine to pass a target-specific option to a target-specific
compilation unit (like -mpclmul to a PCLMUL-specific compilation unit),
that is not safe for mixed-architecture compilation units.

For mixed-architecture compilation units, the correct way is to set
target attributes on the target-specific functions.

There does not seem to be a way to pass target attributes to
function template instantiation. Hence, we must replace the
ExtendImpl template with plain functions crc32_sse42() and
crc32_slow().

We will also remove some inconsistency between
my_crc32_implementation() and mysys_namespace::crc32::Choose_Extend().

The function crc32_pclmul_enabled() will be moved to mysys/crc32/crc32c.cc
so that the detection code will be compiled without -msse4.2 -mpclmul.

The AMD64 PCLMUL accelerated crc32c_3way() will be moved to a new
file crc32c_amd64.cc. In this way, only a few functions that depend
on -msse4.2 in mysys/crc32/crc32c.cc can be declared with
__attribute__((target("sse4.2"))), and most of the file can be compiled
for the generic target.

Last, the file mysys/crc32ieee.cc will be omitted on 64-bit POWER,
because it was dead code (no symbols were exported).

Reviewed by: Vladislav Vaintroub

After the merging of MDEV-24915, 10.6 branch has regressions with handling of
concurrent write load against two or more cluster nodes. These regressions may
surface as cluster hanging, node crashes or data inconsistency. With some test
scenarios, the only visible symptom could be that the BF victim aborting happens
only by innodb lock wait timeout expiration. This would result only to poor
performance (by default 50 sec hang for each BF conflict), and could be somewhat
difficult to diagnose.

This pull request has following fixes to handle concurrent write load from
multiple nodes:

In lock_wait_wsrep_kill(), the victim trx was expected to be only in
TRX_STATE_ACTIVE state. With the delayed BF conflict handling, it can happen
that victim has advanced into pre commit state. This was fixed by choosing
victim both in TRX_STATE_ACTIVE and TRX_STATE_PREPARED states.

Victim transaction may be in several different states at the time of detected
lock conflict, and due to delayed BF aborting practice in MDEV-24915, the victim
may advance further before the actual BF aborting takes place. The BF aborting
in MDEV-24915 did not wake the victim, if it was in the state of waiting for
some other lock (than the one that was blocking the high priority thread).
This anomaly caused the innodb lock wait timeout expiration delays and poor
performance symptom. To fix this, lock_wait_wsrep_kill() now looks if
victim is in lock waiting state, and uses lock_cancel_waiting_and_release()
to cancel this lock wait.

wsrep_bf_abort() checks if the victim has active transaction (in wsrep-lib),
and starts a new transaction if there was no active transaction before.
Due to late BF aborting, the victim may have e.g. failed in certification
and is already aborting or has aborted at this stage. This has caused
problems in testing where BF aborter tries to BF abort himself.
The fix in wsrep_bf_abort() now skips the BF abort, if victim is aborting
or has aborted. Victim may not have started transaction yet in wsrep context,
but it may have acquired MDL locks (due to DDL execution), and this has
caused BF conflict. Such case does not require aborting in wsrep or
replication provider state.

BF aborting could cause BF-BF conflict scenario, if victim was already aborted
and changed to replayer having high priority as well. This BF-BF conflict
scenario is now avoided in lock_wait_wsrep() where we now check if blocking
lock holder is also high priority and is ordered before, caller should wait
for the lock in this situation.

The natural innodb deadlock resolving algorithm could pick BF thread as
deadlock victim. This is fixed by giving max weigh to BF threads in
Deadlock::report().

MDEV-24341 has changed excution paths in do_command() and this affects BF
aborted victim execution. This PR fixes one assert in do_command():
 DBUG_ASSERT(!thd->async_state.pending_ops())
Which fired if the thd was BF aborted earlier. This assert is now changed
to allow pending_ops() if thd was BF aborted before.

With these fixes, long term highly conflicting write load could be run against
to node cluster. If binlogging is configured, log_slave_updates should be
also set.

- Commit 5cc2096f introduced in `10.5` changed DBI:DBD to DBD:MariaDB in this case with redudant `mysql` option.
- According to database handle (dbh) and `connect` method one should follow
  https://metacpan.org/pod/DBD::MariaDB#Class-Methods with proper created data source name (dsn).
- Adding socket precedance over port.
- Adding skipping the comments when reading the `my.cnf` file.
- MDEV-23016: mariadb-setpermission included

Between btr_pcur_store_position() and btr_pcur_restore_position()
it is possible that purge empties a table and enlarges
index->n_core_fields and index->n_core_null_bytes.
Therefore, we must cache index->n_core_fields in
btr_pcur_t::old_n_core_fields so that btr_pcur_t::old_rec can be
parsed correctly.

Unfortunately, this is a huge change, because we will replace
"bool leaf" parameters with "ulint n_core"
(passing index->n_core_fields, or 0 for non-leaf pages).
For special cases where we know that index->is_instant() cannot hold,
we may also pass index->n_fields.

- Fixing post-fix failure. In clean_new_vcol_index(), InnoDB has the wrong
offset to store the virtual column

MDEV-25197: The statement set password=password('') executed in PS mode fails in case it is run by a user with expired password

A user connected to a server with an expired password
can't change password with the statement "SET password=..."
if this statement is run in PS mode. In mentioned use case a user
gets the error ER_MUST_CHANGE_PASSWORD on attempt to run
the statement  PREPARE stmt FOR "SET password=...";

The reason of failure to reset password by a locked user using the
statement PREPARE stmt FOR "SET password=..." is that PS-related
statements are not listed among the commands allowed for execution
by a user with expired password. However, simple adding of PS-related
statements (PREPARE FOR/EXECUTE/DEALLOCATE PREPARE ) to the list of
statements allowed for execution by a locked user is not enough
to solve problems, since it opens the opportunity for a locked user
to execute any statement in the PS mode.

To exclude this opportunity, additional checking that the statement
being prepared for execution in PS-mode is the SET statement has to be added.
This extra checking has been added by this patch into the method
Prepared_statement::prepared() that executed on preparing any statement
for execution in PS-mode.

MDEV-24135: Print warnings in XML, save test retries in XML, save the combinations in XML, replace the special symbols in the XML comment

Assert was:
mariadbd: /my/maria-10.6/wsrep-lib/src/client_state.cpp:256:
int wsrep::client_state::after_statement(): Assertion `state() == s_exec'

The reason was because of two faults:
- A missing test for WSREP(thd) when checking wsrep_after_statement(()
- THD->wsrep_cs().state was set to s_idle instead of s_none

At the second execution of the PS
1. mark_as_dependent() is called with the same parameters as at the first
   execution (select#4 and select#3)
2. as outer_select (select#3) has been already merged at the first
   execution of PS it cannot be reached using the outer_select() function
   anymore (and so can not stop iteration).
3. as a result all selects towards the top level select including the
   select for 'ca' are marked as uncacheable.
4. Marked uncacheable it executed incorrectly triggering filling its
   temporary table several times and using freed memory at the end.

To avoid the problem we use name resolution context to go "up".

NOTE: problem also exists in 10.2 but has no visible effect on execution.
That is why the problem is fixed in 10.2.

The patch also add debug logging of important procedures and
better specify parameters types of st_select_lex::mark_as_dependent.

MDEV-25108: Running of the EXPLAIN EXTENDED statement produces extra warning in case it is executed in PS (prepared statement) mode

The EXPLAIN EXTENDED statement run as a prepared statement can produce extra
warning comparing with a case when EXPLAIN EXTENDED statement is run as
a regular statement. For example, the following test case
  CREATE TABLE t1 (c int);
  CREATE TABLE t2 (d int);
  EXPLAIN EXTENDED SELECT (SELECT 1 FROM t2 WHERE d = c) FROM t1;

produces the extra warning
  "Field or reference 'c' of SELECT #2 was resolved in SELECT #1"
in case the above mentioned "EXPLAIN EXTENDED" statement is executed
in PS mode, that is by submitting the following statements:
   PREPARE stmt FROM "EXPLAIN EXTENDED SELECT (SELECT 1 FROM t2 WHERE d = c) FROM t1";
   EXECUTE stmt;

The reason of the extra warning emittion is in a way items
are handled (being fixed) during execution of the JOIN::prepare() method.
The method Item_field::fix_fields() calls the find_field_in_tables()
function in case a field hasn't been associated yet with the item.
Implementation of the find_field_in_tables() function first checks whether
a table containing the required field was already opened and cached.
It is done by checking the data member item->cached_table. This data member
is set on handling the PRERARE FROM statement and checked on executing
the EXECUTE statement. If the data member item->cached_table is set
the find_field_in_tables() function invoked and the
mark_select_range_as_dependent() function called if the field
is an outer referencee. The mark_select_range_as_dependent() function
calls the mark_as_dependent() function that finally invokes
the push_warning_printf() function that produces extra warning.

To fix the issue, calling of push_warning_printf() is elimited in case
it was run indirectly in result of hanlding already opened table from
the Item_field::fix_fields() method.

This commit removes the mtr test galera_sst_mariabackup_encrypt_with_key
from the list of disabled tests because the problem with it has already
been fixed.

Problem:
========
 InnoDB fails to clean the index stub if it fails to add the
virtual index which contains new virtual column. But it clears
the newly virtual column from index in clear_added_indexes()
during inplace_alter_table. On commit, InnoDB evicts and
reload the table. In case of rollback, it doesn't happen.
InnoDB clears the ABORTED index while opening the table
or doing the DDL. In the mean time, InnoDB can access
the dropped virtual index columns while creating prebuilt
or rollback of concurrent DML.

Solution:
==========
(1) InnoDB should maintain newly added virtual column while
rollbacking the newly added virtual index.
(2) InnoDB must not defer the index removal
if the alter table is executed with LOCK=EXCLUSIVE.
(3) For LOCK=SHARED, InnoDB should check whether the table
has any other transaction lock other than alter transaction
before deferring the index stub.

Replaced has_new_v_col with dict_add_vcol_info in dict_index_t to
indicate whether the index has any new virtual column.

dict_index_t::has_new_v_col(): Returns whether the index has
newly added virtual column, it doesn't say which columns are
newly added virtual column

ha_innobase_inplace_ctx::is_new_vcol(): Return whether the
given column is added as a part of the current alter.

ha_innobase_inplace_ctx::clean_new_vcol_index(): Copy the newly
added virtual column to new_vcol_info in dict_index_t. Replace
the column in the index fields with virtual column stored
in new_vcol_info.

dict_index_t::assign_new_v_col(): Store the number of virtual
column added in index as a part of alter table.

dict_index_t::get_n_new_vcol(): Get the number of newly added
virtual column

dict_index_t::assign_drop_v_col(): Allocate the memory for
adding new virtual column in new_vcol_info.

dict_index_t::add_drop_v_col(): Add the newly added virtual
column in new_vcol_info.

dict_table_t::has_lock_for_other_trx(): Whether the table has
any other transaction lock than given transaction.

row_merge_drop_indexes(): Add parameter alter_trx and check
whether the table has any other lock than alter transaction.

When a table has been evicted from dict_sys and reloaded internally by
InnoDB for FOREIGN KEY processing, statistics may not be initialized,
but nevertheless row_update_cascade_for_mysql() could invoke
dict_stats_update_if_needed(). In that case, we cannot really update
the statistics. For tables that have STATS_PERSISTENT=1 and
STATS_AUTO_RECALC=1, ANALYZE TABLE might have to be executed later.

dict_stats_update_if_needed(): Replace the assertion with
a conditional early return.

trx_sys_any_active_transactions(): Remove a bogus debug assertion.
In trx_commit_in_memory() and trx_erase_lists(), we will remove
the transaction from trx_sys->rw_trx_list and set the state to
TRX_STATE_COMMITTED_IN_MEMORY.

MariaDB Server still supports Ubuntu 16.04 "Xenial" until it goes EOL
in April 30, 2021. Thus we need to include a customization for backwards
compatibility.

This change is intended to be applied for all MariaDB versions still
supported, i.e. 10.2 to 10.6.

The auto-increment variables may change intermittently during
the execution of some tests from the Galera mtr suite, causing
these tests to fail. This patch creates conditions in which
unpredictable changes to these variables are not possible
during the execution of those tests in which this problem
is noticed or their values are restored before the end of
testing.

SST scripts for Galera should use the new mariabackup interface
instead of the innobackupex interface, which is currently only
supported for compatibility reasons.

This commit converts the SST script for mariabackup to use the
new interface. It does not need separate tests, as any problems
will be seen as failures when running multiple tests for the
mariabackup-based SST.

Touch attribute file to fix errors like:
  Can't open ./demoCA/index.txt.attr for reading,
  No such file or directory
  140553384993216:error:02001002:system library:
  fopen:No such file or directory:../crypto/bio/bss_file.c:72:
  fopen('./demoCA/index.txt.attr','r')
  140553384993216:error:2006D080:BIO routines:
  BIO_new_file:no such file:../crypto/bio/bss_file.c:79:
  Check that the request matches the signature

change after MDEV-24197)

problems with ambiguous options in the future.

This patch fixes an issue with launching mariabackup during SST
(when used with Galera), when during bootstrap mariabackup receives
the "--innodb" option, which is incorrectly interpreted as shortcut
for "--innodb-force-recovery". This patch does not require separate
test for mtr, as the problem is visible in general testing on
buildbot.

This reverts commit 51630d59.

Monty has more comprehensive fix coming in his branch.

Move skip_locked near other bools

table name for fts diagnostics

In commit 8ea923f5 (MDEV-24818)
when we optimized multi-statement INSERT transactions into empty tables,
we would roll back the entire transaction on any error. But, we would
fail to invalidate any SAVEPOINT that had been requested in the past.

trx_t::savepoints_discard(): Renamed from trx_roll_savepoints_free().

row_mysql_handle_errors(): If we were in bulk insert, invoke
trx_t::savepoints_discard(). In this way, a future attempt of
ROLLBACK TO SAVEPOINT will return an error.

This fixes the MariaDB-client RPM to conflict with
< MariaDB-server-10.6 as a number of files where moved
from the server to client component.

see commits 09202b2e ->
 fa0ad2fb

In commit 8ea923f5 (MDEV-24818)
when we optimized multi-statement INSERT into an empty table,
we would sometimes wrongly enable bulk insert into a table that
is actually already using row-level locking and undo logging.

trx_has_lock_x(): New predicate, to check if the transaction of
the current thread is holding an exclusive lock on a table.

trx_undo_report_row_operation(): Only invoke
trx_mod_table_time_t::start_bulk_insert() if
trx_has_lock_x() holds.

Handle "col<>const" in the same way that MDEV-21958 did for
"col NOT IN(const-list)": do not use the condition for range/index_merge
accesses if there is a unique UNIQUE KEY(col).

The testcase is in main/range.test. The rest of test updates are
due to widespread use of 'pk<>1' in the testsuite. Changed the test
to use different but equivalent forms of the conditions.