In commit 45ed9dd9 (MDEV-23855)
when removing fil_system.LRU we failed to rate-limit the output
for reporting violations of innodb_open_files or open_files_limit.

If the server is run with a small limit of open files that is
well below the number of .ibd files that are being accessed by
the workload, and if at the same time innodb_log_file_size is
very small so that log checkpoints will occur frequently,
the process of enforcing the open files limit may be run very often.

fil_space_t::try_to_close(): Display at most one message per call,
and only if at least 5 seconds have elapsed since the last time a
message was output.

fil_node_open_file(): Only output a summary message if
fil_space_t::try_to_close() displayed a message during this run.
(Note: multiple threads may execute fil_node_open_file() on
different files at the same time.)

fil_space_t::get(): Do not dereference a null pointer if n & STOPPING.
This was caught by the test case below.

Unfortunately, it is not possible to create a fully deterministic
test case (expecting exactly 1 message to be emitted). The following with
--innodb-open-files=10 --innodb-log-file-size=4m
would occasionally fail to find the message in the log:

--source include/have_innodb.inc
--source include/have_partition.inc
--source include/have_sequence.inc

call mtr.add_suppression("InnoDB: innodb_open_files=10 is exceeded");

CREATE TABLE t1 (pk INT AUTO_INCREMENT PRIMARY KEY) ENGINE=InnoDB
PARTITION BY key (pk) PARTITIONS 100;

INSERT INTO t1 SELECT * FROM seq_1_to_100;
--disable_query_log
let $n=400;
while ($n)
{
BEGIN; DELETE FROM t1; ROLLBACK;
dec $n;
}
--enable_query_log

let SEARCH_FILE= $MYSQLTEST_VARDIR/log/mysqld.1.err;
let SEARCH_PATTERN= \[Note\] InnoDB: Cannot close file;
-- source include/search_pattern_in_file.inc

DROP TABLE t1;

FIXME: Part of the MDEV-20699 test is disabled due to
nonderterministic result.

- Add new Ninja and Clang build jobs. This helps to ensure those
  toolchains also work in addition to default CMake/gcc.

- Generate dependencies.dot/png to illustrate the CMake/Make/Ninja
  build dependencies. Viewing this image and identifying bottle necks
  in parallelism can help make the build run faster.

- Enable CUnit tests now as they are fixed on 10.6 (MDEV-25820).

- Limit parallel builds to 2 CPUs (full parallelism needs MDEV-25968) on
  CMake/Make. Now only the Ninja builds run full parallel builds as only
  Ninja is smart enough to prevent builds failing on resource
  over-consumption.

- Enable Gitlab-CI cache for job 'centos8' for ccache so that it builds
  faster. Don't use Gitlab-CI cache for other jobs, as it would too easily
  use up all free tier storage on Gitlab.com and force users to get a paid
  account just for MariaDB builds.

- On other jobs clean away ccache, as it only had a 5% hit rate on single
  builds with no downloaded cache.

- Dump full database contents during the test install so that one can
  use diff to compare the database contents at different stages and thus
  track/debug potential bugs in mariadb-install-db and mariadb-upgrade
  code.

Bugfixes:

- Zero out ccache stats before each run so that 'ccache -s' would actually
  show the stats for the latest run.

Normally we disable caching of routines in "SHOW CREATE".
Introduce an exception, if debug_dbug="+d,cache_sp_in_show_create".
lock_sync.test needs a way to populate the cache without side effects,
or else it runs into debug_sync timeouts.

So, this possibility to cache will be remain only for very special tests.

Occasionally, after restart, additional transactions will have been
executed, possibly related to innodb_stats_auto_recalc.

We should only care that the transaction ID sequence does
not go backwards.

Apparently, slow shutdown is not necessary anymore after MDEV-15912 fix

Let us mask the actual values of the defragmentation-related fields,
because they may vary. Also, remove the dependency on purge,
and instead delete records by a ROLLBACK of INSERT.

Microsoft does not define inline assembler syntax for AMD64,
but it defines the intrinsic function _interlockedbittestandset()
that we can use.

ssux_lock_impl<bool>::rd_wait(): Remove a call to yield,
because writer.wr_lock() will take care of context switches
between loop iterations.

This addresses suggestions by Vladislav Vaintroub.

timeout is in seconds, sleeptime is in miliseconds. Otherwise we sleep
for 10 times longer than the timeout.

In commit 277ba134
we accidentally omitted this.

Previously, neither our wrapper of Microsoft Windows SRWLOCK
nor the futex-less implementation SUX_LOCK_GENERIC supported spin loops.

This was suggested by Vladislav Vaintroub.

srw_mutex_impl<bool>::wait_and_lock(): In
commit a73eedbf we introduced
an std::atomic::fetch_or() in a loop. Alas, on the IA-32 and AMD64,
that was being translated into a loop around LOCK CMPXCHG.
To avoid a nested loop, it is better to explicitly invoke
std::atomic::compare_exchange_weak() in the loop, but only if
the attempt has a chance to succeed (the HOLDER flag is not set).

It is even more efficient to use LOCK BTS, but contemporary compilers
fail to translate std::atomic::fetch_or(x) & x into that when x is
a single-bit constant. On GCC-compatible compilers, we will use
inline assembler to achieve that.

On other ISA than IA-32 and AMD64, we will continue to use
std::atomic::fetch_or().

ssux_lock_impl<spinloop>::rd_wait(): Use rd_lock_try().
A loop around std::atomic::compare_exchange_weak() should be
cheaper than fetch_add(), fetch_sub() and a wakeup system call.

These deficiencies were pointed out and the use of LOCK BTS was
suggested by Thiago Macieira.

The reason for this behavior is that SP get cached, per connection.
The stored_program_cache is size of this cache, which amounts to 256
routines by default. A compiled stored procedure can easily be several
megabytes in size. Thus calling SHOW CREATE PROCEDURE for all stored
procedures, like mysqldump does, can require significant amount of memory.

Fixed by bypassing the cache for "SHOW CREATE". This should normally be
fine also perfomance-wise, as cache is meant to be used for repeated
execution, not repeated SHOW CREATEs.

Added a test to verify that CREATE PROCEDURE + SHOW CREATE PROCEURE do not
cache, i.e amount of allocated memory does not change.

Note, there is a change in existing behavior in an edge case :
If "SHOW CREATE PROCEDURE p1" called from p1, after p1 was altered, now
this will now return altered code. Previour behavior - relied on caching
and would return old code. The previous behavior might was not necessarily
correct.

MDEV-21613 : galera_sr.GCF-1018B MTR failed: Failed to open table mysql.wsrep_streaming_log for writing

Query can be bf aborted already earlier and then we should not
even try to open table.

Add wait_condition to wait until all nodes are in cluster

Use in_sum_func (and so nest_level) only in LEX to which SELECT lex belong to

Reduce usage of current_select (because it does not always point on the correct
 SELECT_LEX, for example with prepare.

Change context for all classes inherited from Item_ident (was only for Item_field) in case of pushing down it to HAVING.

Now name resolution context have to have SELECT_LEX reference if the context is present.

Fixed feedback plugin stack usage.

Revert 88a4be75 and
9d97f92f, which had been
prematurely pushed by accident.

last commit  8221708e removed too much,
mtr is failing

Problem:
========
InnoDB fails to fetch the page0 from dblwr if page0 is
corrupted.In that case, InnoDB defers the tablespace
and doesn't find the INIT_PAGE redo log record for page0
and it leads to failure.

Solution:
=========
 InnoDB should recover page0 from dblwr if space_id can
be found for deferred tablespace.

Create minidump when server fails to shutdown. If process is being
debugged, cause a debug break.

Moves some code which is part of safe_kill into mysys, as both safe_kill,
and mysqltest produce minidumps on different timeouts.

Small cleanup in wait_until_dead() - replace inefficient loop with a single
wait.

Fixed flaws with overly strict or, conversely,
overly soft verification of certificates in some
scenarios:

1. Removed the check that the 'commonname' (CN) in the
   certificate matches the 'localhost' value on the side
   of the joiner node, which was performed earlier, even
   if the address was received by the script only as an
   argument (out of the exchange via the Galera protocol) -
   since for the joining node this argument always contains
   its own local address, not the address of the remote host,
   so it is always treated as 'localhost', which is not
   necessarily true (outside of mtr testing);
2. Removed checking the domain name or IP-address of the
   peer node in the encrypt=2 mode;
3. Fixed checking of compliance of certificates when
   rsync SST is used;
4. Added the ability to specify CA not only as a file,
   but also as a path to the directory where the certificates
   are stored. To do this, the user just needs to specify the
   path to this directory as the value ssl-ca or tca parameter,
   ending with the '/' character.