innodb_drop_database(): Apply binary comparison.
(SYS_FOREIGN.ID unfortunately uses latin1_swedish_ci collation.)

Another batch of changes that should make the SST process
more reliable in all scenarios:

 1) Added hostname or CN verification when stunnel is used
    with certificate chain verification (verifyChain = yes);
 2) Added check for the absence of the stunnel utility for
    mtr tests;
 3) Deletion of working files before and after SST is done
    more accurately;
 4) rsync on joiner can be run even if the path to its
    configuration file contains spaces;
 5) More accurate directory creation (for data files and
    for logs);
 6) IST with mysqldump no longer turns off statement logging;
 7) Reset password for mysqldump when password is empty but
    username is specified;
 8) More reliable quoting when generating statements in
    wsrep_sst_mysqldump;
 9) Added explicit generation of 2048-bit Diffie-Hellman
    parameters for sockat < 1.7.3, by analogy with xtrabackup;
10) Compression parameters for qpress are read from all
    suitable server groups in configuration file, as well as
    from the [sst] and [xtrabackup] groups;
11) Added a test that checks compression using qpress;
12) Checking for optional utilities is modified to work even
    if they implemented as built-in shell commands (unlikely
    on real systems, but more reliable).

and pass the correct dir in mtr

Move event table change to the group
of the event table changes after which
event scheduler can be started.

make the select from mysql.proc stable and independent from
previous operations on the table.

also, remove redundant drops.

Followup. If the KILL happens - report it as a failure,
don't eat it up silently. Note that this has to be done after `table_name`
is populated, so that the error message could show it.

in win32 stat_info.st_size is __int64, not size_t

suppress columnstore boost warning

The bug is that we don't have a a lock on the trigger name, so it is
possible for two threads to try to create the same trigger at the same
time and both thinks that they have succeed.
Same thing can happen with drop trigger or a combinations of create and
drop trigger.

Fixed by adding a mdl lock for the trigger name for the duration of the
create/drop.

If two threads would call sf_free() / free_memory() at the same time,
bad_ptr() would not detect this. Fixed by adding extra detection
when working with the memory region under sf_mutex.

Other things:
- If safe_malloc crashes while mutex is hold, stack trace printing will
  hang because we malloc is called by my_open(), which is used by stack
  trace printing code. Fixed by adding MY_NO_REGISTER flag to my_open,
  which will disable the malloc() call to remmeber the file name.

The problem was that tdc_remove_referenced_share() did not take into
account that someone could push things into share->free_tables() even
if there is a MDL_EXCLUSIVE lock on the table.
This can happen if flush_tables() uses the table cache to flush a
a non transactional table to disk.

Fixed the ASSERT to take care of the case when table already existed.

The 'special' cases where we disable, suppress or circumvent UBSAN are:
- ref10 source (as here we intentionally do some shifts that UBSAN
  complains about.
- x86 version of optimized int#korr() methods. UBSAN do not like unaligned
  memory access of integers.  Fixed by using byte_order_generic.h when
  compiling with UBSAN
- We use smaller thread stack with ASAN and UBSAN, which forced me to
  disable a few tests that prints the thread stack size.
- Verifying class types does not work for shared libraries. I added
  suppression in mysql-test-run.pl for this case.
- Added '#ifdef WITH_UBSAN' when using integer arithmetic where it is
  safe to have overflows (two cases, in item_func.cc).

Things fixed:
- Don't left shift signed values
  (byte_order_generic.h, mysqltest.c, item_sum.cc and many more)
- Don't assign not non existing values to enum variables.
- Ensure that bool and enum values are properly initialized in
  constructors.  This was needed as UBSAN checks that these types has
  correct values when one copies an object.
  (gcalc_tools.h, ha_partition.cc, item_sum.cc, partition_element.h ...)
- Ensure we do not called handler functions on unallocated objects or
  deleted objects.
  (events.cc, sql_acl.cc).
- Fixed bugs in Item_sp::Item_sp() where we did not call constructor
  on Query_arena object.
- Fixed several cast of objects to an incompatible class!
  (Item.cc, Item_buff.cc, item_timefunc.cc, opt_subselect.cc, sql_acl.cc,
   sql_select.cc ...)
- Ensure we do not do integer arithmetic that causes over or underflows.
  This includes also ++ and -- of integers.
  (Item_func.cc, Item_strfunc.cc, item_timefunc.cc, sql_base.cc ...)
- Added JSON_VALUE_UNITIALIZED to json_value_types and ensure that
  value_type is initialized to this instead of to -1, which is not a valid
  enum value for json_value_types.
- Ensure we do not call memcpy() when second argument could be null.

Other things:

- Changed struct st_position to an OBJECT and added an initialization
  function to it to ensure that we do not copy or use uninitialized
  members. The change to a class was also motived that we used "struct
  st_position" and POSITION randomly trough the code which was
  confusing.
- Notably big rewrite in sql_acl.cc to avoid using deleted objects.
- Changed in sql_partition to use '^' instead of '-'. This is safe as
  the operator is either 0 or 0x8000000000000000ULL.
- Added check for select_nr < INT_MAX in JOIN::build_explain() to
  avoid bug when get_select() could return NULL.
- Reordered elements in POSITION for better alignment.
- Changed sql_test.cc::print_plan() to use pointers instead of objects.
- Fixed bug in find_set() where could could execute '1 << -1'.
- Added variable have_sanitizer, used by mtr.  (This variable was before
  only in 10.5 and up).  It can now have one of two values:
  ASAN or UBSAN.
- Moved ~Archive_share() from ha_archive.cc to ha_archive.h and marked
  it virtual. This was an effort to get UBSAN to work with loaded storage
  engines. I kept the change as the new place is better.
- Added in CONNECT engine COLBLK::SetName(), to get around a wrong cast
  in tabutil.cpp.

Changes that should not be needed but had to be done to suppress warnings
from UBSAN:

- Added static_cast<<uint16_t>> around shift to get rid of a LOT of
  compiler warnings when using UBSAN.
- Had to change some '/' of 2 base integers to shift to get rid of
  some compile time warnings.

Fixes:

MDEV-25505 Assertion `old_flags == ((my_flags & 0x10000U) ? 1 : 0)
fixed (was caused by an old version if this commit).

Reviewed by:
- Json changes: Alexey Botchkov
- Charset changes in ctype-uca.c: Alexander Barkov
- InnoDB changes: Marko Mäkelä
- sql_acl.cc changes: Vicențiu Ciorbaru
- build_explain() changes: Sergey Petrunia
Temporary commit to log changes for UBSAN

Disabled show_explain when used with valgrind because of random failures
Disable ssl-big when running with --valgrind as it takes more than 1 hour

- mariadbd and mariadbd-env added
- Changed output of print_global_resfile to use mariadbd instead of mysqld

Many of the changes was needed to be able to collect and print engine
name and table version id's in the ddl log.

This is done by prefixing -backup.log to the --log-ddl-recovery file.
The reason for this is to have a copy of the original ddl log file
if ddl recovery does not succeed.

MDEV-25604 Atomic DDL: Binlog event written upon recovery does not
           have default database

The purpose of this task is to ensure that ALTER TABLE is atomic even if
the MariaDB server would be killed at any point of the alter table.
This means that either the ALTER TABLE succeeds (including that triggers,
the status tables and the binary log are updated) or things should be
reverted to their original state.

If the server crashes before the new version is fully up to date and
commited, it will revert to the original table and remove all
temporary files and tables.
If the new version is commited, crash recovery will use the new version,
and update triggers, the status tables and the binary log.
The one execption is ALTER TABLE .. RENAME .. where no changes are done
to table definition. This one will work as RENAME and roll back unless
the whole statement completed, including updating the binary log (if
enabled).

Other changes:
- Added handlerton->check_version() function to allow the ddl recovery
  code to check, in case of inplace alter table, if the table in the
  storage engine is of the new or old version.
- Added handler->table_version() so that an engine can report the current
  version of the table. This should be changed each time the table
  definition changes.
- Added  ha_signal_ddl_recovery_done() and
  handlerton::signal_ddl_recovery_done() to inform all handlers when
  ddl recovery has been done. (Needed by InnoDB).
- Added handlerton call inplace_alter_table_committed, to signal engine
  that ddl_log has been closed for the alter table query.
- Added new handerton flag
  HTON_REQUIRES_NOTIFY_TABLEDEF_CHANGED_AFTER_COMMIT to signal when we
  should call hton->notify_tabledef_changed() during
  mysql_inplace_alter_table. This was required as MyRocks and InnoDB
  needed the call at different times.
- Added function server_uuid_value() to be able to generate a temporary
  xid when ddl recovery writes the query to the binary log. This is
  needed to be able to handle crashes during ddl log recovery.
- Moved freeing of the frm definition to end of mysql_alter_table() to
  remove duplicate code and have a common exit strategy.

-------
InnoDB part of atomic ALTER TABLE
(Implemented by Marko Mäkelä)
innodb_check_version(): Compare the saved dict_table_t::def_trx_id
to determine whether an ALTER TABLE operation was committed.

We must correctly recover dict_table_t::def_trx_id for this to work.
Before purge removes any trace of DB_TRX_ID from system tables, it
will make an effort to load the user table into the cache, so that
the dict_table_t::def_trx_id can be recovered.

ha_innobase::table_version(): return garbage, or the trx_id that would
be used for committing an ALTER TABLE operation.

In InnoDB, table names starting with #sql-ib will remain special:
they will be dropped on startup. This may be revisited later in
MDEV-18518 when we implement proper undo logging and rollback
for creating or dropping multiple tables in a transaction.

Table names starting with #sql will retain some special meaning:
dict_table_t::parse_name() will not consider such names for
MDL acquisition, and dict_table_rename_in_cache() will treat such
names specially when handling FOREIGN KEY constraints.

Simplify InnoDB DROP INDEX.
Prevent purge wakeup

To ensure that dict_table_t::def_trx_id will be recovered correctly
in case the server is killed before ddl_log_complete(), we will block
the purge of any history in SYS_TABLES, SYS_INDEXES, SYS_COLUMNS
between ha_innobase::commit_inplace_alter_table(commit=true)
(purge_sys.stop_SYS()) and purge_sys.resume_SYS().
The completion callback purge_sys.resume_SYS() must be between
ddl_log_complete() and MDL release.

--------

MyRocks support for atomic ALTER TABLE
(Implemented by Sergui Petrunia)

Implement these SE API functions:
- ha_rocksdb::table_version()
- hton->check_version = rocksdb_check_versionMyRocks data dictionary
  now stores table version for each table.
  (Absence of table version record is interpreted as table_version=0,
  that is, which means no upgrade changes are needed)
- For inplace alter table of a partitioned table, call the underlying
  handlerton when checking if the table is ok. This assumes that the
  partition engine commits all changes at once.

ALTER TABLE .. RENAME, when used with the inplace algorithm, does:
- Do an inplace or online alter to the new definition
- Rename to new name
- Update triggers.

If update triggers would fail, we would rename the table back.
The problem with this approach is that the table would have the new
definition but the rename would fail.  The binary log would also not be
updated.

The solution to this is to very early check if we can rename triggers
and give an error if this would fail.
Both ALTER TABLE ... RENAME and RENAME TABLE is fixed.

This was implemented by moving the pre-check of rename table in triggers
from Table_triggers_list::change_table_name() to
Table_triggers_list::prepare_for_rename().

Before this fix, one would get a 'Trigger ... already exists' when trying
to create a trigger matching the original name and 'Trigger ... does not
exists" when trying to drop it.

Fixes a reported bug in MDEV-25180 Atomic ALTER TABLE

MDEV-25517 Atomic DDL: Assertion `query_arg' in THD::binlog_query
upon DROP TRIGGER

The bug was that the stmt_query variable was not populated
with the query in case of DROP TRIGGER of an orphan trigger
(.TRN file exists & table exists, but the trigger was not in
table->triggers).

The purpose of this task is to ensure that CREATE TRIGGER is atomic

When a trigger is created, we first create a trigger_name.TRN file and then
create or update the table_name.TRG files.
This is done by creating .TRN~ and .TRG~ files and replacing (or creating)
the result files.

The new logic is

- Log CREATE TRIGGER to DDL log, with a marker if old trigger existsted
- If old .TRN or .TRG files exists, make backup copies of these
- Create the new .TRN and .TRG files as before
- Remove the backups

Crash recovery
- If query has been logged to binary log:
  - delete any left over backup files
- else
   - Delete any old .TRN~ or .TRG~ files
   - If there was orignally some triggers (old .TRG file existed)
      - If we crashed before creating all backup files
         - Delete existing backup files
      - else
         - Restore backup files
      - end
   - Delete .TRN and .TRG file (as there was no triggers before

One benefit of the new code is that CREATE OR REPLACE TRIGGER is now
totally atomic even if there existed an old trigger: Either the old
trigger will be replaced or the old one will be left untouched.

Other things:
- If sql_create_definition_file() would fail, there could be memory leaks
  in CREATE TRIGGER, DROP TRIGGER or CREATE OR REPLACE TRIGGER.  This
  is now fixed.

The logic of the new code is:
- Log CREATE view to DDL log, with a marker if old view existed
- If old view exists (in case of CREATE or REPLACE view), make a copy
  of the old view as view_name.frm-
- Create the new view definition file
- Delete copy of view if it was created.

Crash recovery:
- Delete view_name.frm~ file (Temporary file for view definition)
- If query was logged to binary log
  - Delete copy of view if it exists
- else
   -rename the copy of the view over the .frm file (restoring the
    old definition)

One benefit of the new code is that CREATE OR REPLACE VIEW for an
existing view is no fully atomic: Either the view will be replaced or
the old one will be left unchanged.

There are a few different cases to consider

Logging of CREATE TABLE and CREATE TABLE ... LIKE
- If REPLACE is used and there was an existing table, DDL log the drop of
  the table.
- If discovery of table is to be done
    - DDL LOG create table
  else
    - DDL log create table (with engine type)
    - create the table
- If table was created
  - Log entry to binary log with xid
  - Mark DDL log completed

Crash recovery:
- If query was in binary log do nothing and exit
- If discoverted table
   - Delete the .frm file
-else
   - Drop created table and frm file
- If table was dropped, write a DROP TABLE statement in binary log

CREATE TABLE ... SELECT required a little more work as when one is using
statement logging the query is written to the binary log before commit is
done.
This was fixed by adding a DROP TABLE to the binary log during crash
recovery if the ddl log entry was not closed. In this case the binary log
will contain:
CREATE TABLE xxx ... SELECT ....
DROP TABLE xxx;

Other things:
- Added debug_crash_here() functionality to Aria to be able to test
  crash in create table between the creation of the .MAI and the .MAD files.

Description of how DROP DATABASE works after this patch

- Collect list of tables
- DDL log tables as they are dropped
- DDL log drop database
- Delete db.opt
- Delete data directory
- Log either DROP TABLE or DROP DATABASE to binary log
- De active ddl log entry

This is in line of how things where before (minus ddl logging) except that
we delete db.opt file last to not loose it if DROP DATABASE fails.

On recovery we have to ensure that all dropped tables are logged in
binary log and that they are properly dropped (as with atomic drop
table).
No new tables be dropped as part of recovery.

Recovery of active drop database ddl log entry:

- If drop database was logged to ddl log but was not found in the binary
  log:
  - drop the db.opt file and database directory.
  - Log DROP DATABASE to binary log
- If drop database was not logged to ddl log
  - Update binary log with DROP TABLE of the dropped tables. If table list
    is longer than max_allowed_packet, then the query will be split into
    multiple DROP TABLE/VIEW queries.

Other things:
- Added DDL_LOG_STATE and 'current database' as arguments to
  mysql_rm_table_no_locks(). This was needed to be able to combine
  ddl logging of DROP DATABASE and DROP TABLE and make the generated
  DROP TABLE statements shorter.
- To make the DROP TABLE statement created by ddl log shorter, I changed
  the binlogged query to use current directory and omit the directory
  part for all tables in the current directory.
- Merged some DROP TABLE and DROP VIEW code in ddl logger.  This was done
  to be able get separate DROP VIEW and DROP TABLE statements in the binary
  log.
- Added a 'recovery_state' variable to remember the state of dropped
  tables and views.
- Moved out code that drops database objects (stored procedures) from
  mysql_rm_db_internal() to drop_database_objects() for better code reuse.
- Made mysql_rm_db_internal() global so that could be used by the ddl
  recovery code.

The purpose of this task is to ensure that DROP TRIGGER is atomic.

Description of how atomic drop trigger works:

Logging of DROP TRIGGER
    Log the following information:
    db
    table name
    trigger name
    xid /* Used to check if query was already logged to binary log */
    initial length of the .TRG file
    query if there is space for it, if not log a zero length query.

Recovery operations:
- Delete if exists 'database/trigger_name.TRN~'
  - If this file existed, it means that we crashed before the trigger
    was deleted and there is nothing else to do.
- Get length of .TRG file
  - If file length is unchanged, trigger was not dropped. Nothing else to
    do.
- Log original query to binary, if it was stored in the ddl log. If it was
  not stored (long query string), log the following query to binary log:
  use `database` ; DROP TRIGGER IF EXISTS `trigger_name`
  /* generated by ddl log */;

Other things:
- Added trigger name and DDL_LOG_STATE to drop_trigger()
  Trigger name was added to make the interface more consistent and
  more general.