Use SetThreadDescription/pthread_setname_np to give threads a name.

Several variables declared in mysqld.h appear to be old system variables
that have been left over after deprecation. Delete them using IDE
refactoring to automatically search for other uses. Most cases had no
other uses in the code.

slave_allow_batching had a test that was effectively unused, as the
result was only
-ERROR HY000: Unknown system variable 'slave_allow_batching'
so that was deleted as well.

Build and test still works without issue as expected.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services.

The problem was using safe_table_name() instead of safe_table_name().str
with DBUG_PRINT

Storage engines generally expects that my_errno is set in case of errors

Affects:
MDEV-34150 Assertion failure in Diagnostics_area::set_error_status upon binary
           logging hitting tmp space limit
MDEV-9101 Limit size of created disk temporary files and tables

This bug was caused by moving flushing of the in-memory-row-events from
close_thread_tables() to binlog_commit() in MDEV-34150.
This was needed to be able to handle the case where binlog writes could
fail.

Galera have two case where the change caused problems:

- Row events in commit_one_phase_2() was not done in the case the standard
  binary log was not enabled but Galera was using the binary log
  internally.
- Galera disabled the call to binlog_commit_flush_stmt_cache() for not
  ending transactions.

Fixed by adding code that flushes the in-memory-row-events to the binary
log (write, but now sync) in the two above cases if Galera is enabled.

realloc can't be done for mysql->passwd. There's also no pretty way to
pass the ext-salt into hash_password, so let's use thread_local instead.

For GCC < 4.9 (SLES 12, CentOS 7), which don't support _Thread_local,
pk will be recalculated instead

Apart from better performance when accessing thread local variables,
we'll get rid of things that depend on initialization/cleanup of
pthread_key_t variables.

Where appropriate, use compiler-dependent pre-C++11 thread-local
equivalents, where it makes sense, to avoid initialization check overhead
that non-static thread_local can suffer from.

Make it clear that refactoring code goes into the latest version.

Since MDEV-25829 Change default Unicode collation to uca1400_ai_ci
there is no need to set character-set-collations explicitly as its
the default.

Further mode the change in defaults affects all character sets that
support the uca1400_ai_ci collation.

This avoids a lot of SETVAL() results when applying a mysqldump with
sequences.

To make this possible, it was also necessary to enhance the mariadb
client with the option --print-query-on-error.
This option can also be very useful when running a batch of queries
through the mariadb client and one wants to find out where things goes
wrong.

TODO: It would be good to enhance mariadb_upgrade to not call the mariadb
client for executing queries but instead do this internally.  This
would have made this patch much easier!

Reviewed by: Sergei Golubchik <serg@mariadb.com>

- During recovery, InnoDB may fail to shrink the undo tablespaces
when there are no pages to recover while applying the redo log.
This issue exists only when innodb_undo_truncate is enabled.
trx_lists_init_at_db_start() could've applied the redo logs
for undo tablespace page0.

This fixes up the merge commit 829cb1a4

- InnoDB ignores the error while traversing the used
extents during shrinking process. Made changes in
fsp_traverse_extents() to handle error condition
correctly

On an UBSAN clang-15 build, if running with UBSAN option
halt_on_error=1 (the issue doesn't show up without it),
MTR fails during mysqld --bootstrap with UBSAN error:

call to function io_callback(tpool::aiocb*) through pointer to incorrect function type 'void (*)(void *)'

This patch corrects the parameter type of io_callback
to match its expected type defined by callback_func,
i.e. (void*).

Reviewed By:
============
<TODO>

Problem:
=======
During recovery, InnoDB fails to apply the redo log for
compressed tablespace. The reason is that InnoDB assumes
that pages has been freed while applying the redo log for it.
During multiple scan of redo logs, InnoDB stores the freed
page information when it have sufficient buffer pool pages.
Once it ran out of memory, InnoDB doesn't store freed page
information. But InnoDB assigns the freed page ranges to tablespace
in recv_init_crash_recovery_spaces() even though
InnoDB doesn't have complete freed range information.
While applying the redo log, InnoDB wrongly assumes that page
has been freed and it could lead to corruption of tablespace.
This issue is caused by commit 941af1fa (MDEV-31803)
and commit 2f9e2647 (MDEV-29911).

Solution:
========
During recovery, set recovery size and freed page information
for all tablespace irrespective of memory.

The bug can happens on macOS, if server closes the socket without sending
error packet to client. Closing the socket on server side is legitimate,
and happen e.g when write timeout occurs, perhaps also other situations.

However mysqltest is not prepared to handle mysql_errno 0, and erroneously
thinks connection was successfully established.

The fix/workaround in mysqltest is to treat client failure with
mysql_errno 0 the same as CR_SERVER_LOST (generic client-side
communication error)

The real fix in client library would ensure that mysql_errno is set
on errors.

Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

Otherwise it may result in nonsensical values like 190 for a boolean.

Implement automatic creation of temporary accounts for SST and pass
account credentials to SST script via socket as opposed to environment
variables. Delete the user after the SST script returns,

Respect wsrep_sst_auth set by the adminitrator in case some additional
privilege grants are needed for particular SST method.

mysqldump SST requires significant change to make use of the new
automatic user generation facility. For now just make it compatible
by ignoring automatically generated user and rely only on wsrep_sst_auth
setting on the joiner node to keep backward compatibility.

Adapt mysqldump SST to automatic SST user generation changes:
 - disable special treatment for mysqldump SST on donor
 - make mysqldump SST script compatible with the new SST script
   interface.

Differentiate user privileges for different SST methods:
 - grant minimum required privileges for clone and xtrabackup SST
   accounts
 - grant all privileges to custom SST accounts as it is not known what
   is needed.
 - disable SST account generation for rsync SST since it is not needed.

MTR tests:
 - add MTR tests for clone and xtrabackup SSTs without wsrep_sst_auth,
 - add MTR test for testing masking of wsrep_sst_auth.
 - don't attmept to restore original wsrep_sst_auth in MTR tests as it
   is always masked.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>