Before this change the unix socket auth plugin returned true only when
the OS socket user id matches the MariaDB user name.
The authentication string was ignored.

Now if an authentication string is defined with in `unix_socket`
authentication rule, then the authentication string will be used to
compare with the socket's user name, and the plugin will return a
positive if matching.

Make the plugin to fill in the @@external_user variable.

This change is similar to MySQL commit of
https://github.com/mysql/mysql-server/commit/6ddbc58e.
However there's one difference with above commit:

- For MySQL, both Unix user matches DB user name and Unix user matches the
  authentication string will be allowed to connect.
- For MariaDB, we only allows the Unix user matches the authentication
  string to connect, if the authentication string is defined.
  This is because allowing both Unix user names has risks and couldn't
  handle the case that a customer only wants to allow one single Unix user
  to connect which doesn't matches the DB user name.

If DB user is created with multiple unix_socket options for example:
`create user A identified via unix_socket as 'B' or unix_socket as 'C';`
Then both Unix user of B and C are accepted.

Existing MTR test of `plugins.unix_socket` is not impacted.
Also add a new MTR test to verify authentication with authentication
string. See the MTR test cases for supported/unsupported cases.

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, Inc.

MDEV-33856: Alternative Replication Lag Representation via Received/Executed Master Binlog Event Timestamps

This commit adds 3 new status variables to 'show all slaves status':

- Master_last_event_time ; timestamp of the last event read from the
  master by the IO thread.
- Slave_last_event_time ; Master timestamp of the last event committed
  on the slave.
- Master_Slave_time_diff: The difference of the above two timestamps.

All the above variables are NULL until the slave has started and the
slave has read one query event from the master that changes data.

- Added information_schema.slave_status, which allows us to remove:
   - show_master_info(), show_master_info_get_fields(),
     send_show_master_info_data(), show_all_master_info()
   - class Sql_cmd_show_slave_status.
   - Protocol::store(I_List<i_string_pair>* str_list) as it is not
     used anymore.
- Changed old SHOW SLAVE STATUS and SHOW ALL SLAVES STATUS to
  use the SELECT code path, as all other SHOW ... STATUS commands.

Other things:
- Xid_log_time is set to time of commit to allow slave that reads the
  binary log to calculate Master_last_event_time and
  Slave_last_event_time.
  This is needed as there is not 'exec_time' for row events.
- Fixed that Load_log_event calculates exec_time identically to
  Query_event.
- Updated RESET SLAVE to reset Master/Slave_last_event_time
- Updated SQL thread's update on first transaction read-in to
  only update Slave_last_event_time on group events.
- Fixed possible (unlikely) bugs in sql_show.cc ...old_format() functions
  if allocation of 'field' would fail.

Reviewed By:
Brandon Nesterenko <brandon.nesterenko@mariadb.com>
Kristian Nielsen <knielsen@knielsen-hq.org>

Cleanup unnecessary whitespace at the end of lines and end of files
in the unittest/ directory. Note that all code changes are
non-functional.

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, Inc.

As this is MariaDB then also variable names in
mariadb-server.*inst should correlate when possible
this change variable and directory names

Gain MySQL compatibility by allowing table aliases in a single
table statement.

This now supports the syntax of:

DELETE [delete_opts] FROM tbl_name [[AS] tbl_alias] [PARTITION (partition_name [, partition_name] ...)] ....

The delete.test is from MySQL commit 1a72b69778a9791be44525501960b08856833b8d
/ Change-Id: Iac3a2b5ed993f65b7f91acdfd60013c2344db5c0.

Co-Author: Gleb Shchepa <gleb.shchepa@oracle.com> (for delete.test)

Reviewed by Igor Babaev (igor@mariadb.com)

Result file needed re-recording to account for the
new information_schema columns

With that, it is possible to restore the full "instance" from a backup
made with mariadb-dump --dir

The patch implements executing DDL (tables, views, triggers) using
statements that are stored in .sql file, created by mariadb-dump
--dir .

Care is taken of creating triggers correctly after the data is loaded,
disabling foreign keys and unique key checks etc.

The files are loaded in descending order by datafile size -
to ensure better work distribution when running with --parallel option.

In addition to --dir option, following options are implemented for
partial restore

include-only options:
--database             -  import one or several databases
--table                -  import one or several tables

exclude options:
--ignore-database      -. ignore one or several databases when importing
--ignore-table         -  to ignore one or several tables when importing

All options above are only valid together with --dir option,
and can be specified multiple times.

Use threadpool, instead of one-thread-and-connection-per-table

Fix tpool to not use maintenance timer for fixed pool size.

Trivial batch, using the handler statistics already collected for
the slow query log.

The reason for the changes in test cases was mainly to change to use
select TABLE_SCHEMA ... from information_schema.table_statistics instead
of 'show table_statistics' to avoid future changes to test results
if we add more columns to table_statistics.

There is no need for a character-set-server configuration when utf8mb4
is now the server default.

Also remove the character-set-collations as its no longer required and
the uca1400_ai_ci is now the default for all character sets that support
it. ref: MDEV-25829 / MDEV-34430.

Changing the default server character set from latin1 to utf8mb4.

Rename some threads to workaround this restrictions,
e.g "rpl_parallel_thread"->"rpl_parallel",
"slave_background" -> "slave_bg" etc.

Use SetThreadDescription/pthread_setname_np to give threads a name.

Use SetThreadDescription/pthread_setname_np to give threads a name.

Builders:
- amd64-fedora-38-last-N-failed
- amd64-debian-10-last-N-failed
erroneously execute MTR for these files:

- rpl/include/rpl_extra_col_master.test
- rpl/include.rpl_binlog_max_cache_size.test
- rpl/include.rpl_charset.test

when these files are changed by a commit.
Changing their extension from *.test to *.inc to avoid this.

my_like_range*() can create longer keys than Field::char_length().
This caused warnings during print_range().

Fix:

Suppressing warnings in print_range().

Line numbers had to be removed from the ignorelists in order to be
diffed against since locations of the same findings can differ
across runs. Therefore preprocessing has to be done on the CI findings
so that it can be compared to the ignorelist and new findings can be
outputted. However, since line numbers have to be removed, a situation
occurs where it is difficult to reference the location of findings
in code given the output of the CI job.

To lessen this pain, change the cppcheck template to include
code snippets which make it easier to reference where in the code
the finding is referring to, even in the absence of line numbers.
Ignorelisting works as before since locations of the finding may
change but not the code it is referring to.

Furthermore, due to the innate difficulty in maintaining ignorelists
across branches and triaging new findings, allow failure as to not
have constantly failing pipelines as a result of a new findings that
have not been addressed yet.

Lastly, update SAST ignorelists to match the newly refactored cppcheck
job and the current state of the codebase.

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, Inc.

Rectify cases of mismatched brackets and address
possible cases of division by zero by checking if
the denominator is zero before dividing.

No functional changes were made.

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, Inc.

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.

crc32_avx512(): Explicitly cast ssize_t(size) to make it clear that
we are indeed applying a negative offset to a pointer.

The issue was that when repairing an Aria table of row format PAGE and
the data file was bigger the 4G, the data file length was cut short
because of wrong parameters to MY_ALIGN().

The effect was that ALTER TABLE, OPTIMIZE TABLE or REPAIR TABLE would fail
on these tables, possibly corrupting them.
The MDEV also exposed a bug where error state was not propagated properly
to the upper level if the number of rows in the table changed.

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

The current semi-sync binlog fail-over recovery process uses
rpl_semi_sync_slave_enabled==TRUE as its condition to truncate a
primary server’s binlog, as it is anticipating the server to re-join
a replication topology as a replica. However, for servers configured
with both rpl_semi_sync_master_enabled=1 and
rpl_semi_sync_slave_enabled=1, if a primary is just re-started (i.e.
retaining its role as master), it can truncate its binlog to drop
transactions which its replica(s) has already received and executed.
If this happens, when the replica reconnects, its gtid_slave_pos can
be ahead of the recovered primary’s gtid_binlog_pos, resulting in an
error state where the replica’s state is ahead of the primary’s.

This patch changes the condition for semi-sync recovery to truncate
the binlog to instead use the configuration variable
--init-rpl-role, when set to SLAVE. This allows for both
rpl_semi_sync_master_enabled and rpl_semi_sync_slave_enabled to be
set for a primary that is restarted, and no transactions will be
lost, so long as --init-rpl-role is not set to SLAVE.

Reviewed By:
============
Sergei Golubchik <serg@mariadb.com>

The special logic used by the memory storage engine
to keep slaves in sync with the master on a restart can
break replication. In particular, after a restart, the
master writes DELETE statements in the binlog for
each MEMORY-based table so the slave can empty its
data. If the DELETE is not executable, e.g. due to
invalid triggers, the slave will error and fail, whereas
the master will never see the problem.

Instead of DELETE statements, use TRUNCATE to
keep slaves in-sync with the master, thereby bypassing
triggers.

Reviewed By:
===========
Kristian Nielsen <knielsen@knielsen-hq.org>
Andrei Elkin <andrei.elkin@mariadb.com>

During read only mode, InnoDB doesn't allow checkpoint to happen.
So InnoDB should throw the warning when InnoDB tries to
force the checkpoint when innodb_read_only = 1 or
innodb_force_recovery = 6.

MariaDB supports a "wait-free concurrent allocator based on pinning addresses".
In `lf_pinbox_real_free()` it tries to sort the pinned addresses for better
performance to use binary search during "real free". `alloca()` was used to
allocate stack memory and copy addresses.

To prevent a stack overflow when allocating the stack memory the function checks
if there's enough stack space. However, the available stack size was calculated
inaccurately which eventually caused database crash due to stack overflow.

The crash was seen on MariaDB 10.6.11 but the same code defect exists on all
MariaDB versions.

A similar issue happened previously and the fix in fc2c1e43 was to add a
`ALLOCA_SAFETY_MARGIN` which is 8192 bytes. However, that safety margin is not
enough during high connection workloads.

MySQL also had a similar issue and the fix
https://github.com/mysql/mysql-server/commit/b086fda was to remove the use of
`alloca` and replace qsort approach by a linear scan through all pointers (pins)
owned by each thread.

This commit is mostly the same as it is the only way to solve this issue as:
1. Frame sizes in different architecture can be different.
2. Number of active (non-null) pinned addresses varies, so the frame
   size for the recursive sorting function `msort_with_tmp` is also hard
   to predict.
3. Allocating big memory blocks in stack doesn't seem to be a very good
   practice.

For further details see the mentioned commit in MySQL and the inline comments.

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, Inc.