Creation of tables by the three names mysql.user, mysql.host, mysql.db
was being blocked in the function row_mysql_is_system_table().

Since commit 4abb8216 (MDEV-17658),
mysql.user is a view, not a table. Since commit
ead9a34a (MDEV-15851), mysql.host
is not being created at all.

Let us remove the special handling of table names in InnoDB,
and allow mysql.db to be created in InnoDB. The special handling
was originally added in commit e84ef2b7
without any explanation.

Reviewed by: Sergei Golubchik

Problem:
=======
There are two issues that are addressed in this patch:
 1) SHOW BINARY LOGS uses caching to store the binary logs that exist
in the log directory; however, if new events are written to the logs,
the caching strategy is unaware. This is okay for users, as it is
okay for SHOW to return slightly old data. The test, however, can
result in inconsistent data. It runs two connections concurrently,
where one shows the logs, and the other adds a new file. The output
of SHOW BINARY LOGS then depends on when the cache is built, with
respect to the time that the second connection rotates the logs.
 2) There is a race condition between RESET MASTER and SHOW BINARY
LOGS. More specifically, where they both need the binary log lock to
begin, SHOW BINARY LOGS only needs the lock to build its cache. If
RESET MASTER is issued after SHOW BINARY LOGS has built its cache and
before it has returned the results, the presented data may be
incorrect.

Solution:
========
 1) As it is okay for users to see stale data, to make the test
consistent, use DEBUG_SYNC to force the race condition (problem 2) to
make SHOW BINARY LOGS build a cache before RESET MASTER is called.
Then, use additional logic from the next part of the solution to
rebuild the cache.
 2) Use an Atomic_counter to keep track of the number of times RESET
MASTER has been called. If the value of the counter changes after
building the cache, the cache should be rebuilt and the analysis
should be restarted.

Reviewed By:
============
Andrei Elkin: <andrei.elkin@mariadb.com>

Audit-plugin related fixes.

The call to the function fts_check_corrupt() was removed
in commit 09af00cb already.

Server crashes in Field::register_field_in_read_map upon select from
partitioned table with indexed by prefix virtual column.

After several read-mark fixes a problem has surfaced:
Since KEY (c(10),a) uses only a prefix of c, a new field is created,
duplicated from table->field[3], with a new length. However,
vcol_inco->expr is not copied.

Therefore, (*key_info)->key_part[i].field->vcol_info->expr was left NULL
in ha_partition::index_init().

Solution: copy vcol_info from table field when it's set up.

This reverts commit 9b8e207c.

fix main.processlist_notembedded test

* before EXPLAINing `select sleep` wait for select to start
  (fixes "Target is not running an EXPLAINable command")
* after killing sleep, wait for it to die
  (fixes test failures on --repeat when old sleep shows on a test rerun)

* unify with 10.3, copy minor changes from there
  (`--echo End of 5.5` vs `--echo # End of 5.5`, etc)

len was containing garbage, since vctempl->mysql_col_offset was
containing old value while calling row_mysql_store_col_in_innobase_format
from innobase_get_computed_value().

It was not updated after the first ALTER TABLE call, because it's INPLACE
logic considered there's nothing to update, and exited immediately from
ha_innobase::inplace_alter_table().

However, vcol metadata needs an update, since vcols structure is changed
in mysql record.

The regression was introduced by 12614af1. There, refcount==1 condition
was removed, which turned out to be crucial, though racy. The idea was to
update vc_templ after each (sequencing) ALTER TABLE.

We should do the same another way, and there may be a plenty of solutions,
but the simplest one is to add a following condition:
  if vcol structure is changed, drop vc_templ; it will be recreated on next
  ha_innobase::open() call.

in prepare_inplace_alter_table. It is safe, since innodb inplace changes
require at least HA_ALTER_INPLACE_SHARED_LOCK_AFTER_PREPARE, which
guarantee MDL_EXCLUSIVE on this stage.

alter_templ_needs_rebuild() also has to track the columns not indexed, to
keep vc_templ correct.

Note that vc_templ is always kept constructed and available after
ha_innobase::open() call, even on INSERT, though no virtual columns are
evaluated during that statement
inside innodb.

In the test case suplied, it will be recreated on the second ALTER TABLE.

ha_innobase::prepare_inplace_alter_table(): Remove always-true conditions.
Near the start of the function, we would already have returned if
no ALTER TABLE operation flags were set that would require special
action from InnoDB.

It turns out that the conditions were redundant already when they were
introduced in mysql/mysql-server@241387a2b6b61fb8a4f78dc4ad0aaa289400c694
and in commit 068c6197.

Thanks to Nikita Malyavin for noticing this.

When creating fields for UNION results, Field_null is not allowed.
Should create binary(0) instead.

Pass char* to WSREP_LOG and others, instead of non-POD objects

Add a couple of NO_XXX prprocessor constants to wolfssl build.
Looked into cmake defaults, those are set there too. Some of
these are (supposedly) weak ciphers, and some just fallen out from wide
use.

This patch fixes the bug that TRIM(BOTH ... FROM $str), TRIM(LEADING ... FROM $str),
and TRIM(TRAILING ... FROM $str) failed with errors when executing on Spider.

Victim threads which are in currently in process of aborting or already
aborted should be skipped for another kill process.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

MDEV-25740 Assertion `!wsrep_has_changes(thd) || (thd->lex->sql_command == SQLCOM_CREATE_TABLE && !thd->is_current_stmt_binlog_format_row())' failed in void wsrep_commit_empty(THD*, bool)

Using ROLLBACK with `completion_type = CHAIN` result in start of
transaction and implicit commit before previous WSREP internal data is
cleared.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

MDEV-22421 Galera assertion !wsrep_has_changes(thd) || (thd->lex->sql_command == SQLCOM_CREATE_TABLE && !thd->is_current_stmt_binlog_format_row())

Updates to transaction registry table shouldn't be replicated in
cluster so there is no need to append wsrep keys.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

Server crashes in Field::register_field_in_read_map upon select from
partitioned table with indexed by prefix virtual column.

After several read-mark fixes a problem has surfaced:
Since KEY (c(10),a) uses only a prefix of c, a new field is created,
duplicated from table->field[3], with a new length. However,
vcol_inco->expr is not copied.

Therefore, (*key_info)->key_part[i].field->vcol_info->expr was left NULL
in ha_partition::index_init().

Solution: initialize vcols before key initialization

Also key initialization is moved to a function.

Thanks to Nikita Malyavin for noticing this.
The dead code that was originally introduced in
mysql/mysql-server@b8bd31740cd7088f3a3c164981c7ccda487d301d
was added in commit 2e814d47
to this code base.

rename files `version` -> `version_full`

FetchIndexRootPages::operator(): handle REDUNDANT vs DYNAMIC case specifically.
Other combinations seems fine as is.

This is important since Sys_var_typelib and its descendants return
pointers to constant symbols from *_value_ptr, which are situated in
write-protected-memory.

* functions const-qualified:
  - value_ptr
  - session_value_ptr
  - global_value_ptr
  - default_value_ptr
  - Sys_var_vers_asof::value_ptr
  - other minor private ones

* remove C-style typecasts when it discards qualifiers

MDEV-16026: Forbid global system_versioning_asof in non-default time zone

* store `system_versioning_asof` in unix time;
* both session and global vars are processed in session timezone;
* setting `default` does not copy global variable anymore. Instead, it sets
  system_time to SYSTEM_TIME_UNSPECIFIED, which means that no 'AS OF' time
  is applied and `now()` can be assumed

As a regression, we cannot assign values below 1970 (UTC) anymore

MDEV-16481: set global system_versioning_asof=sf() crashes in specific case

* sys_vars.h: add `MYSQL_TIME` field to `set_var::save_result`
* sys_vars.ic: get rid of calling `var->value->get_date()` from
 `Sys_var_vers_asof::update()`
* versioning.sysvars: add test; remove double warning

refactor Sys_var_vers_asof

* inherit from sys_var rather than Sys_var_enum
* remove junk "DEFAULT" keyword. There is DEFAULT in SQL grammar for it.
* make all conversions in check() to avoid possible errors
* avoid double var->value evaluation, which could
  consequence in undefined behavior

Workaround WolfSSL bug https://github.com/wolfSSL/wolfssl/issues/4242
(heap overflow) by using fastmath library everywhere, except Windows clang

Before the patch, default math library was used on all 32bit platforms.

btr_scrub_start_space(): Avoid an unnecessary tablespace lookup
and related acquisition of fil_system->mutex. In MariaDB Server 10.3
we would get deadlocks between that mutex and a crypt_data mutex.

The fix was developed by Thirunarayanan Balathandayuthapani.