- Remove second optional parameter to natural_sort_key(), and all fraction
handling.

- Rename natsort_num2str() to natsort_encode_length() to show the intention
that it encodes string *lengths*, and not encode whitespaces and what not.

Handles lengths for which log10(len) >= 10,  even if they do not happen for
MariaDB Strings (where length is limited by 32bit, and log10(len) is <= 9)

- Do not let natural sort key grow past max_packet_length.


- Split Item_func_natural_sort_key::val_str() further and add
natsort_encode_numeric_string(), which contains comment on how
whitespaces are handled.

- Simplify, and speedup to_natsort_key() in common case, by removing
handling of weird charsets utf16/32, that encode numbers in several bytes.
In rare cases utf16/32 is used, we'll convert to utf8 prior to
creating keys, and back to original charset afterwards.

The numbers should be compared as numbers,  while the rest should be compared
as string.

Introduce natural_sort_key() function that transforms original string
so that the lexicographic order of such keys is suitable for
natural sort.

innodb_max_dirty_pages_pct_update(),
innodb_max_dirty_pages_pct_lwm_update():
Invoke buf_pool.page_cleaner_wakeup() in order to wake up
buf_flush_page_cleaner. This allows the test innodb.page_cleaner
to run without any occasional timeouts.

The occasional hangs were introduced by
commit 7b1252c0 (MDEV-24278).

Add wait_condition

10.5 version

The changes to galera.galear_var_replicate_myisam_on
in commit d9b933be
are omitted due to conflicts
with commit 27d66d64.

The test galera.galera_var_replicate_myisam_on
would trigger an assertion failure "mode() == m_local"
in wsrep-lib/src/client_state.cpp after the merge
of commit 3067ffc5 enabled it.

In commit 1cb218c3 (MDEV-26450)
we introduced the function log_write_and_flush(), which may
compete with log_checkpoint() invoking log_write_flush_to_disk_low()
from another thread.

The assertion n_pending_flushes==1 is too strict.
There is no possibility of a race condition here, because
fil_flush() is protected by fil_system->mutex and the
rest will be protected by log_sys->mutex.

log_write_flush_to_disk_low(), log_write_and_flush():
Relax the assertions to test for a nonzero count.

Debian stretch is supported until Jun 2022.

MyRocks definitavely does require 1.1.3+.

Mroonga has never been zstd enabled, though
support for it exists in the codebase.

While a 1.1.3+ version exists in stretch backports
we don't support this.

Fixes: b67210b1054118fe14b6346bdee3f9bbd3416870

If charset aggregation decides to convert arguments to some specific
charset and some arguments are numbers, they'll be wrapped into a
Item_func_conv_charset(), that changes result_type() to STRING_RESULT.

Fix: don't convert numbers, sformat needs their numerical value only.

libfmt must be built before sql or sql_embedded target, since compilation
of item_strfunc.cc depends on it.

Previously, GenServerSource depended on libfmt,yet this GenServerSource
is not a  direct or indirect dependency of sql, if -DPLUGIN_PERFSCHEMA=NO
is used in cmake configuration step.

1. it is against sql way, auto-detection should use metadata, not data,
consider:

create table t1 (qwe varchar(10)) as values ('qwe'),('qw'),('q'),('werty');
select sformat('{:*>5s}', qwe) from t1;

this will auto-break on the third row.

2. using max_char_length() instead of length() fixes that, but
there's a second big issue, fmt < 8.0 doesn't natively support unicode,
so {:c} would only work for one-byte strings, for 'a', not for 'я'

because of all that let's always format strings as strings.
{:c} will only now work for numbers and still only in the ascii range.

libfmt 6.1 is in Ubuntu focal repositories.
it's easy to compile with 6.1 by doing
#define detail internal

but 6.1 also produces different results in main.func_sformat
and we want MariaDB to behave identically everywhere.

String inherits from Sql_alloc, so it's allocated on the thd's memroot,
this cannot be done per row.

Moved String[] allocation into the Item_func_sformat constructor
(not fix_fields(), because we want it on the same memroot where the item
is).

by printing a String as an std::string_view, not as a char*

* comment - use the standard style
* no need to reimplement for with while
* TODO comments for not implemented types
* rename the error not to refer to the underlying library, it's
  the implementation detail
* use res->length(0) to set length to 0, but preserve the already
  allocated buffer
* rename main.sformat -> main.func_sformat
* removed a duplicated part of the test

SFORMAT() SQL function that uses fmtlib (https://fmt.dev/)
for python-like (also Rust, C++20, etc) string formatting

Only fmtlib 7.0.0+ is supported, older fmtlib
produces different results in the test.

No native support for temporal and decimal values,
* TIME_RESULT is handled as STRING_RESULT
* DECIMAL_RESULT as REAL_RESULT

Explicitly devide two function of 0 length in the hash keys comparing.

No empty name roles exists (no sens to look for).
The problem already present in our test cases.

Prohibit user variables without name

Get rid of locking "empty" plugin.
This problem present in our tests in case of malformed frm-file, for example.

MDEV-26637: (explicit length) ASAN: main.metadata and user_variables.basic MTR failures after MDEV-26572

Use explicit length for hash record length

Before clang-10, asm goto was not supported, so we must use fetch_or().

Update wsrep-lib, and add MTR test case for MDEV-26707
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

- Add libconfig-inifiles-perl to mariadb-client depends as mytop uses it
  https://salsa.debian.org/mariadb-team/mariadb-10.5/-/commit/7a748da87a23eb874d0bddb64114a795e9d07e6d
  http://bugs.debian.org/875708

- Make libzstd dependency versioned as RocksDB need at least 1.3.3
  https://salsa.debian.org/mariadb-team/mariadb-10.5/-/commit/da4eb54fc0c2ded0e10243fe1d81bf7e105a25c3

  However, https://github.com/facebook/rocksdb/blob/master/INSTALL.md
  implies that zstandard 1.1.3 would suffice. Version 1.3.x is available
  from Debian Stretch-backports and Ubuntu Xenial onwards.

Also fixes MDEV-24467 Memory not freed after failed INSERT DELAYED

Description:

In case of an error (e.g. data truncation) during mysql_insert()
handling an INSERT DELAYED, the data type specific data in
fields (e.g. Field_blob::value) is not taken over by the delayed
writer thread.

All fields in table_list->table are freed by free_root()
immediately after mysql_insert(). To avoid a memory leak,
we need to free the specific data before exiting mysql_insert()
on error.

The crash happened because my_isalnum() does not support character
sets with mbminlen>1.

The value of "ft_boolean_syntax" is converted to utf8 in do_string_check().
So calling my_isalnum() is combination with "default_charset_info" was wrong.

Adding new parameters (size_t length, CHARSET_INFO *cs) to
ft_boolean_check_syntax_string() and passing self->charset(thd)
as the character set.

The crash happened because Item_aes_crypt::val_str() did not
set the character set of the result.

Co-authored-by: FX Coudert <fxcoudert@gmail.com>