The purpose of dict_table_t::stats_bg_flag was to prevent
race conditions between DDL operations and a background thread
that updates persistent statistics for InnoDB tables.

Now that with the parent commit, we started to acquire a
shared meta-data lock (MDL) on the InnoDB persistent statistics tables
in background tasks that access them, we may easily acquire MDL
on the table for which the statistics are being updated. This will by
design prevent race conditions with any DDL operations on that table,
and the stats_bg_flag may be removed.

dict_stats_process_entry_from_recalc_pool(): Complete rewrite.
During the processing, retain the entry in recalc_pool, so
that dict_stats_recalc_pool_del() will be able to request
deletion of the entry, or delete the entry if its caller is
holding MDL_EXCLUSIVE while we are waiting for MDL.

recalc_pool: In addition to the table ID, store a state for
inter-thread communication, so that dict_stats_recalc_pool_del()
can wait until all processing is finished.

Reviewed by: Thirunarayanan Balathandayuthapani

In commit 1bd681c8 (MDEV-25506 part 3)
we introduced a "fake instant timeout" when a transaction would wait
for a table or record lock while holding dict_sys.latch. This prevented
a deadlock of the server but could cause bogus errors for operations
on the InnoDB persistent statistics tables.

A better fix is to ensure that whenever a transaction is being
executed in the InnoDB internal SQL parser (which will for now
require dict_sys.latch to be held), it will already have acquired
all locks that could be required for the execution. So, we will
acquire the following locks upfront, before acquiring dict_sys.latch:

(1) MDL on the affected user table (acquired by the SQL layer)
(2) If applicable (not for RENAME TABLE): InnoDB table lock
(3) If persistent statistics are going to be modified:
(3.a) MDL_SHARED on mysql.innodb_table_stats, mysql.innodb_index_stats
(3.b) exclusive table locks on the statistics tables
(4) Exclusive table locks on the InnoDB data dictionary tables
(not needed in ANALYZE TABLE and the like)

Note: Acquiring exclusive locks on the statistics tables may cause
more locking conflicts between concurrent DDL operations.
Notably, RENAME TABLE will lock the statistics tables
even if no persistent statistics are enabled for the table.

DROP DATABASE will only acquire locks on statistics tables if
persistent statistics are enabled for the tables on which the
SQL layer is invoking ha_innobase::delete_table().
For any "garbage collection" in innodb_drop_database(), a timeout
while acquiring locks on the statistics tables will result in any
statistics not being deleted for any tables that the SQL layer
did not know about.

If innodb_defragment=ON, information may be written to the statistics
tables even for tables for which InnoDB persistent statistics are
disabled. But, DROP TABLE will no longer attempt to delete that
information if persistent statistics are not enabled for the table.

This change should also fix the hangs related to InnoDB persistent
statistics and STATS_AUTO_RECALC (MDEV-15020) as well as
a bug that running ALTER TABLE on the statistics tables
concurrently with running ALTER TABLE on InnoDB tables could
cause trouble.

lock_rec_enqueue_waiting(), lock_table_enqueue_waiting():
Do not issue a fake instant timeout error when the transaction
is holding dict_sys.latch. Instead, assert that the dict_sys.latch
is never being held here.

lock_sys_tables(): A new function to acquire exclusive locks on all
dictionary tables, in case DROP TABLE or similar operation is
being executed. Locking non-hard-coded tables is optional to avoid
a crash in row_merge_drop_temp_indexes(). The SYS_VIRTUAL table was
introduced in MySQL 5.7 and MariaDB Server 10.2. Normally, we require
all these dictionary tables to exist before executing any DDL, but
the function row_merge_drop_temp_indexes() is an exception.
When upgrading from MariaDB Server 10.1 or MySQL 5.6 or earlier,
the table SYS_VIRTUAL would not exist at this point.

ha_innobase::commit_inplace_alter_table(): Invoke
log_write_up_to() while not holding dict_sys.latch.

dict_sys_t::remove(), dict_table_close(): No longer try to
drop index stubs that were left behind by aborted online ADD INDEX.
Such indexes should be dropped from the InnoDB data dictionary by
row_merge_drop_indexes() as part of the failed DDL operation.
Stubs for aborted indexes may only be left behind in the
data dictionary cache.

dict_stats_fetch_from_ps(): Use a normal read-only transaction.

ha_innobase::delete_table(), ha_innobase::truncate(), fts_lock_table():
While waiting for purge to stop using the table,
do not hold dict_sys.latch.

ha_innobase::delete_table(): Implement a work-around for the rollback
of ALTER TABLE...ADD PARTITION. MDL_EXCLUSIVE would not be held if
ALTER TABLE hits lock_wait_timeout while trying to upgrade the MDL
due to a conflicting LOCK TABLES, such as in the first ALTER TABLE
in the test case of Bug#53676 in parts.partition_special_innodb.
Therefore, we must explicitly stop purge, because it would not be
stopped by MDL.

dict_stats_func(), btr_defragment_chunk(): Allocate a THD so that
we can acquire MDL on the InnoDB persistent statistics tables.

mysqltest_embedded: Invoke ha_pre_shutdown() before free_used_memory()
in order to avoid ASAN heap-use-after-free related to acquire_thd().

trx_t::dict_operation_lock_mode: Changed the type to bool.

row_mysql_lock_data_dictionary(), row_mysql_unlock_data_dictionary():
Implemented as macros.

rollback_inplace_alter_table(): Apply an infinite timeout to lock waits.

innodb_thd_increment_pending_ops(): Wrapper for
thd_increment_pending_ops(). Never attempt async operation for
InnoDB background threads, such as the trx_t::commit() in
dict_stats_process_entry_from_recalc_pool().

lock_sys_t::cancel(trx_t*): Make dictionary transactions immune to KILL.

lock_wait(): Make dictionary transactions immune to KILL, and to
lock wait timeout when waiting for locks on dictionary tables.

parts.partition_special_innodb: Use lock_wait_timeout=0 to instantly
get ER_LOCK_WAIT_TIMEOUT.

main.mdl: Filter out MDL on InnoDB persistent statistics tables

Reviewed by: Thirunarayanan Balathandayuthapani

que_eval_sql(): Remove the parameter lock_dict. The only caller
with lock_dict=true was dict_stats_exec_sql(), which will now
explicitly invoke dict_sys.lock() and dict_sys.unlock() by itself.

row_import_cleanup(): Do not unnecessarily lock the dictionary.
Concurrent access to the table during ALTER TABLE...IMPORT TABLESPACE
is prevented by MDL and the fact that there cannot exist any
undo log or change buffer records that would refer to the table
or tablespace.

row_import_for_mysql(): Do not unnecessarily lock the dictionary
while accessing fil_system. Thanks to MDL_EXCLUSIVE that was acquired
by the SQL layer, only one IMPORT may be in effect for the table name.

row_quiesce_set_state(): Do not unnecessarily lock the dictionary.
The dict_table_t::quiesce state is documented to be protected by
all index latches, which we are acquiring.

dict_table_close(): Introduce a simpler variant with fewer parameters.

dict_table_close(): Reduce the amount of calls.
We can simply invoke dict_table_t::release() on startup or
in DDL operations, or when the table is inaccessible.
In none of these cases, there is no need to invalidate the
InnoDB persistent statistics.

pars_info_t::graph_owns_us: Remove (unused).

pars_info_free(): Define inline.

fts_delete(), trx_t::evict_table(), row_prebuilt_free(),
row_rename_table_for_mysql(): Simplify.

row_mysql_lock_data_dictionary(): Remove some references;
use dict_sys.lock() and dict_sys.unlock() instead.

row_mysql_lock_table(): Remove. Use lock_table_for_trx() instead.

ha_innobase::check_if_supported_inplace_alter(),
row_create_table_for_mysql(): Simply assert dict_sys.sys_tables_exist().
In commit 49e2c8f0 and
commit 1bd681c8 srv_start()
actually guarantees that the system tables will exist,
or the server is in read-only mode, or startup will fail.

Reviewed by: Thirunarayanan Balathandayuthapani

sym_tab_free_private(): Do not call dict_table_close(), but
simply invoke dict_table_t::release(), which we can do without
locking the whole dictionary cache. (Note: On user tables it
may still be necessary to invoke dict_table_close(), so that
InnoDB persistent statistics will be deinitialized as expected.)

fts_check_corrupt(), row_fts_merge_insert(): Invoke
aux_table->release() to simplify the code. This is never a user table.

fts_que_graph_free(), fts_que_graph_free_check_lock(): Replaced with
que_graph_free().

Reviewed by: Thirunarayanan Balathandayuthapani

In the parent commit, dict_sys.latch could theoretically have been
replaced with a mutex. But, we can do better and merge dict_sys.mutex
into dict_sys.latch. Generally, every occurrence of dict_sys.mutex_lock()
will be replaced with dict_sys.lock().

The PERFORMANCE_SCHEMA instrumentation for dict_sys_mutex
will be removed along with dict_sys.mutex. The dict_sys.latch
will remain instrumented as dict_operation_lock.

Some use of dict_sys.lock() will be replaced with dict_sys.freeze(),
which we will reintroduce for the new shared mode. Most notably,
concurrent table lookups are possible as long as the tables are present
in the dict_sys cache. In particular, this will allow more concurrency
among InnoDB purge workers.

Because dict_sys.mutex will no longer 'throttle' the threads that purge
InnoDB transaction history, a performance degradation may be observed
unless innodb_purge_threads=1.

The table cache eviction policy will become FIFO-like,
similar to what happened to fil_system.LRU
in commit 45ed9dd9.
The name of the list dict_sys.table_LRU will become somewhat misleading;
that list contains tables that may be evicted, even though the
eviction policy no longer is least-recently-used but first-in-first-out.
(Note: Tables can never be evicted as long as locks exist on them or
the tables are in use by some thread.)

As demonstrated by the test perfschema.sxlock_func, there
will be less contention on dict_sys.latch, because some previous
use of exclusive latches will be replaced with shared latches.

fts_parse_sql_no_dict_lock(): Replaced with pars_sql().

fts_get_table_name_prefix(): Merged to fts_optimize_create().

dict_stats_update_transient_for_index(): Deduplicated some code.

ha_innobase::info_low(), dict_stats_stop_bg(): Use a combination
of dict_sys.latch and table->stats_mutex_lock() to cover the
changes of BG_STAT_SHOULD_QUIT, because the flag is being read
in dict_stats_update_persistent() while not holding dict_sys.latch.

row_discard_tablespace_for_mysql(): Protect stats_bg_flag by
exclusive dict_sys.latch, like most other code does.

row_quiesce_table_has_fts_index(): Remove unnecessary mutex
acquisition. FLUSH TABLES...FOR EXPORT is protected by MDL.

row_import::set_root_by_heuristic(): Remove unnecessary mutex
acquisition. ALTER TABLE...IMPORT TABLESPACE is protected by MDL.

row_ins_sec_index_entry_low(): Replace a call
to dict_set_corrupted_index_cache_only(). Reads of index->type
were not really protected by dict_sys.mutex, and writes
(flagging an index corrupted) should be extremely rare.

dict_stats_process_entry_from_defrag_pool(): Only freeze the dictionary,
do not lock it exclusively.

dict_stats_wait_bg_to_stop_using_table(), DICT_BG_YIELD: Remove trx.
We can simply invoke dict_sys.unlock() and dict_sys.lock() directly.

dict_acquire_mdl_shared()<trylock=false>: Assert that dict_sys.latch is
only held in shared more, not exclusive mode. Only acquire it in
exclusive mode if the table needs to be loaded to the cache.

dict_sys_t::acquire(): Remove. Relocating elements in dict_sys.table_LRU
would require holding an exclusive latch, which we want to avoid
for performance reasons.

dict_sys_t::allow_eviction(): Add the table first to dict_sys.table_LRU,
to compensate for the removal of dict_sys_t::acquire(). This function
is only invoked by INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS.

dict_table_open_on_id(), dict_table_open_on_name(): If dict_locked=false,
try to acquire dict_sys.latch in shared mode. Only acquire the latch in
exclusive mode if the table is not found in the cache.

Reviewed by: Thirunarayanan Balathandayuthapani

This will essentially make dict_sys.latch a mutex
(it is only acquired in exclusive mode).

The subsequent commit will merge dict_sys.mutex into dict_sys.latch
and reintroduce dict_sys.freeze() for those cases where we currently
acquire only dict_sys.latch but not dict_sys.mutex. The case where
both are acquired will be mapped to dict_sys.lock().

i_s_sys_tables_fill_table_stats(): Invoke dict_sys.prevent_eviction()
and the new function dict_sys.allow_eviction() to avoid table eviction
while a row in INFORMATION_SCHEMA.INNODB_SYS_TABLESTATS is being
produced.

Reviewed by: Thirunarayanan Balathandayuthapani

row_purge_remove_clust_if_poss_low(): When dict_table_open_on_id()
is being invoked with the data dictionary locked, it will not
actually acquire MDL. Remove the MDL that became dead code in
commit c366845a.

Change logic to only allocate purge thds at startup, or
in pre-shutdown (for slow shutdown).

THD::copy_db_to(): Always return true if the output parameter
was left uninitialized. This fixes a regression that was caused
by commit 7d0d934c (MDEV-16473).

MariaDB Server 10.3 and later were unaffected by this bug
thanks to commit a7e352b5.

Possibly this bug only affects mysql_list_fields()
in the Embedded Server (libmysqld).

This bug was found by GCC 11.2.0 in CMAKE_BUILD_TYPE=RelWithDebInfo.

init_mutex_v1_t: Stop lying that the mutex parameter is const.
GCC 11.2.0 assumes that it is and could complain about any mysql_mutex_t
being uninitialized even after mysql_mutex_init() as long as
PLUGIN_PERFSCHEMA is enabled.

init_rwlock_v1_t, init_cond_v1_t: Remove untruthful const qualifiers.

Note: init_socket_v1_t is expecting that the socket fd has already
been created before PSI_SOCKET_CALL(init_socket), and therefore that
parameter really is being treated as a pointer to const.

if all options from a combination from the combinations file are already
present in the server's list of options, then don't try to run tests
in other combinations from this file.

old behavior was: if at least one option from a combination is
already present in the list...

(this was needed only for tokudb that bundled liblzma)

replaced CPACK_RPM_PACKAGE_VERSION with SERVER_VERSION.
CPACK_* variables are empty and can't be used until INCLUDE(CPack) is
called.
SERVER_VERSION is the safest option because other variables may be
overwritten from submodules

Thanks to Theodore Brockman on Zulip for noticing
on an OSX ARM64 and testing this patch.

Per https://github.com/google/cpu_features/pull/150/files
CMAKE_SYSTEM_PROCESSOR is arm64 on Apple.

Without this, compulation error:

[ 80%] Building CXX object storage/rocksdb/CMakeFiles/rocksdblib.dir/rocksdb/util/crc32c.cc.o
/mariadb/storage/rocksdb/rocksdb/util/crc32c.cc:500:18: error: use of undeclared identifier 'isSSE42'
  has_fast_crc = isSSE42();
                 ^
/mariadb/storage/rocksdb/rocksdb/util/crc32c.cc:1230:7: error: use of undeclared identifier 'isSSE42'
  if (isSSE42()) {
      ^
/mariadb/storage/rocksdb/rocksdb/util/crc32c.cc:1231:9: error: use of undeclared identifier 'isPCLMULQDQ'
    if (isPCLMULQDQ()) {
        ^

This can be reverted when the RocksDB submodule is updated.

https://github.com/facebook/rocksdb/commit/ee4bd4780b321ddb5f92a0f4eb956f2a2ebd60dc

The problem was that a PREARE followed by a non prepared statement
using DEFAULT NEXT_VALUE() could change table->next_local to point to
a not persitent memory aria. The next EXECUTE would then try to use
the wrong pointer, which could cause a crash.
Fixed by reseting the pointer to it's old value when doing EXECUTE.

Backported patch from MariaDB 10.6
The issue was that the using session_mem_used to break a test does not
guarantee where the test breaks, which gives different results
depending on the environment or how MariaDB is compield.

Buggy sepdebugcrcfix in CentOS 7 (rpm-4.11.3) does not restore
SUID bit after editing the binary. This is fixed in rpm-4.12.

Still let's not set SUID bit when installing auth_pam_tool
and use rpm spec %attr directive instead.

In a rebase of the merge, two preceding commits were accidentally reverted:
commit 112b2396 (MDEV-26308)
commit ac2857a5 (MDEV-25717)

Thanks to Daniele Sciascia for noticing this.

Changes:
- Don't include port in connection parameters with 'localhost' hostname

More info:

The hostname, if not specified or specified as '' or 'localhost', will default
to a MySQL server running on the local machine using the default for the UNIX socket.
To connect to a MySQL server on the local machine via TCP, you must specify the
loopback IP address (127.0.0.1) as the host.

To comply with what the perl module expects, we omit the port for a
host=localhost connection.

Reported issue: https://bugzilla.redhat.com/show_bug.cgi?id=1976224

FLUSH PRIVILEGES hasn't been needed for very many years.

Changes:
- Don't include port in connection parameters with 'localhost' hostname

More info:
The hostname, if not specified or specified as '' or 'localhost', will default
to a MySQL server running on the local machine using the default for the UNIX socket.
To connect to a MySQL server on the local machine via TCP, you must specify the
loopback IP address (127.0.0.1) as the host.

Reported issue: https://bugzilla.redhat.com/show_bug.cgi?id=1976224

Currently @@version_compile_machine is used by mtr
to determine if the compiled executable is 32 or 64
bits.

We extend that logic by ensuring that if the DEFAUT_MACHINE
name doesn't have "64" in its string, "-64bits" is appended
to ensure these test pass.

trx_purge_rseg_get_next_history_log(): Fix a race condition that
was introduced in commit e46f76c9
(MDEV-15912). The buffer pool page contents must not be accessed
while not holding a page latch. The page latch was released by
mtr_t::commit().

This race resulted in an ASAN heap-use-after-poison during a stress test.