btr_cur_optimistic_insert(): Disregard DEBUG_DBUG injection to
invoke btr_page_reorganize() if the page (and the table) is empty.
Otherwise, an assertion would fail in btr_page_reorganize_low()
because PAGE_MAX_TRX_ID is 0 in an empty secondary index leaf page.

Fixed by not sending --group option to the server (for now)

Reviwer: Sergei Golubchik

udf_handler::fix_fields(): Execute an assignment outside "if"
so that GCC 12 will not issue a bogus-looking warning.
Also, deduplicate some error handling code.

DEBUG_SYNC signals can get lost in certain tests due to later
DEBUG_SYNC commands overwriting them. This patch addresses
these issues in three tests: main.query_cache_debug,
main.partition_debug_sync, and
rpl.rpl_dump_request_retry_warning.

Additionally, main.partition_debug_sync needed changes to the
result file (the others did not). The synchronization happened
between two commands, one based on ALTER, the other on DROP.
A new thread/connection was needed to synchronize the DEBUG_SYNC
actions between these commands, thereby changing the result file.
Additional comments were added for clarification.

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

This commit adds validation of the values of the ssl-mode parameter
in SSL scripts, since now only a basic check for the presence of the
"VERIFY_" prefix is performed there to detect "VERIFY_IDENTITY" and
"VERIFY_CA", but all other values are not checked at all.

In addition, this commit removes leading and trailing spaces from
parameter values that SST scripts read from configuration files or
from the command line so that they do not interfere with parameter
checks and substitutions. Parameter substitution has been made more
robust against characters in strings that the shell might erroneously
interpret as regexp.

This commit fixes problems due to bugs and quirks in bsdtar
(the FreeBSD version of tar). Separate tests are not required,
because without these fixes, many other tests fail when tested
in the FreeBSD environment.

Also, the grep patterns for reading utility version numbers
has been made more robust. The notation of some options of
the "cut" utility has been changed.

This commit adds correct handling of binlogs for SST using rsync
or mariabackup. Before this fix, binlogs were handled incorrectly -
- only one (last) binary log file was transferred during SST, which
then led to various failures (for example, when trying to list all
events from the binary log). These bugs were long masked by flaws
in the primitive binlogs handling code in the SST scripts, which
causing binary logs files to be erased after transfer or not added
to the binlog index on the joiner node. Now the correct transfer
of all binary logs (not just the last of the binary log files) has
been implemented both for the rsync (at the script level) and for
the mariabackup (at the level of the main utility code).

This commit also adds a new sst_max_binlogs=<n> parameter, which
can be located in the [sst] section or in the [xtrabackup] section
(historically, supported for mariabackup only, not for rsync), or
in one of the server sections. This parameter specifies the number
of binary log files to be sent to the joiner node during SST. This
option is added for compatibility with old SST scripting behavior,
which can be emulated by setting the sst_max_binlogs=1 (although
in general this can cause problems for the reasons described above).
In addition, setting the sst_max_binlogs=0 can be used to suppress
the transmission of binary logs to the joiner nodes during SST
(although sometimes a single file with the current binary log can
still be transmitted to the joiner, even with sst_max_binlogs=0,
because this sometimes necessary in modes that involve the use of
GTIDs with Galera).

Also, this commit ensures correct handling of paths to various
innodb files and directories in the SST scripts, and fixes some
problems with this that existed in mariabackup utility (which
were associated with incorrect handling of the innodb_data_dir
parameter in some scenarios).

In addition, this commit contains the following enhancements:

 1) Added tests for mtr, which check the correct work with binlogs
    after SST (using rsync and mariabackup);
 2) Added correct handling of slashes at the end of all paths that
    the SST script receives as parameters;
 3) Improved parsing code for --mysqld-args parameters. Now it
    correctly processes the sequence "--" after the name of the
    one-letter option;
 4) Checking the secret signature during joiner authentication
    is made independent of presence of bash (as a unix shell)
    in the system and diff utility no longer needed to check
    certificates compliance;
 5) All directories that are necessary for the correct placement
    of various logs are automatically created by SST scripts in
    advance (before running mariabackup on the joiner node);
 6) Removal of old binary logs on joiner is done using the binlog
    index (if it exists) (not only by fixed pattern that based
    on the current binlog name, as before);
 7) Paths for placing binary logs are correctly processed if they
    are set as relative paths (to the datadir);
 8) SST scripts are made even more resistant to spaces in filenames
    (now for binlogs);
 9) In case of failure, SST scripts now always end with an exit
    code other than zero;
10) SST script for rsync now correctly create a tar file with
    the binlogs, even if the paths to them (in the binlog index
    file) are specified as a mix of absolute and relative paths,
    and even if they do not match with the datadir path specified
    in the current configuration settings.

This commit adds the missing line to the .result file for compress_qpress
(in the mariabackup test suite).

(Edits by SergeiP: fix encryption.tempfiles_encrypted, re-word comment)

Global ORDER BY clause of a UNION may not refer to 1) aggregate functions
or 2) window functions.  setup_order() checked for #1 but not for #2.

SELECTs inside a UNION can have window function but not the global ORDER BY clause of the UNION.

[Patch idea by Igor Babaev]

Symptom: for IN (SELECT ...) subqueries using IN-to-EXISTS transformation,
the optimizer was unable to make inferences using multiple equalities.

The cause is code Item_in_subselect::inject_in_to_exists_cond() which may
break invariants that Multiple-Equality code relies on. In particular, it
may produce a WHERE condition with an empty Item_cond::m_cond_equal.

Fixed this by making Item_cond::m_cond_equal.

The result is not used anywhere but in the output of Innodb information
schema, but this can take as much as 7%CPU (only) on a benchmark.

Fix to move fs blocksize calculate to where it is used.

decrease innodb_lock_wait_timeout for the current session.

convert_error_code_to_mysql(): Use the correct limit FK_MAX_CASCADE_DEL
in the error message. The DICT_FK_MAX_RECURSIVE_LOAD applies to
the number of foreign key constraints in table definitions,
not to the number of rows that are visited while processing
a foreign key constraint.

On FreeBSD, the error message would say "Resource deadlock avoided".
Let us simply replace the error message string in the test.

Some GNU/Linux distributions ship a zlib that is modified to use
the s390x DFLTCC instruction. That modification would essentially
redefine compressBound(sourceLen) as (sourceLen * 16 + 2308) / 8 + 6.

Let us relax the tests for InnoDB ROW_FORMAT=COMPRESSED to cope with
such a weaker compression guarantee.

create_table_info_t::row_size_is_acceptable(): Remove a bogus debug-only
assertion that would fail to hold for the test innodb_zip.bug36169.
The function page_zip_empty_size() may indeed return 0.

The rpl.rpl_seconds_behind_master_spike test would sometimes
timeout or take a very long time to complete. This happened
because an MTR DEBUG_SYNC signal would be lost due to a
subsequent call to RESET. I.e., the slave SQL thread would
be paused due to the WAIT_FOR signal being lost, resulting in
either a failed test if the `select master_pos_wait` timeout
occurs first, or a very long run-time if the DBUG_SYNC timeout
occurs first.

The fix ensures that the MTR signal is processed by the slave
SQL thread before issuing the call to RESET

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

MDEV-27746 Wrong comparision of BLOB's empty preffix with non-preffixed BLOB causes rows count mismatch for clustered and secondary indexes during non-locking read

row_sel_sec_rec_is_for_clust_rec() treats empty BLOB prefix field in
secondary index as a field equal to any external BLOB field in clustered
index. Row_sel_get_clust_rec_for_mysql::operator() doesn't zerro out
clustered record pointer in row_search_mvcc(), and row_search_mvcc()
thinks that delete-marked secondary index record has visible for
"CHECK TABLE"'s read view old-versioned clustered index record, and
row_scan_index_for_mysql() counts it as a row.

The fix is to execute row_sel_sec_rec_is_for_blob() in
row_sel_sec_rec_is_for_clust_rec() if clustered field contains BLOB's
reference.

The asserion failure was caused by this query

  select /*id=1*/ from t1
  where
   col= ( select /*id=2*/ from ... where corr_cond1
          union
          select /*id=4*/ from ... where corr_cond2)

Here,
- select with id=2 was correlated due to corr_cond1.
- select with id=4 was initially correlated due to corr_cond2, but then
  the optimizer optimized away the correlation, making the select with id=4
  uncorrelated.

However, since select with id=2 remained correlated, the execution had to
re-compute the whole UNION. When it tried to execute select with id=4, it
hit an assertion  (join buffer already free'd).

This is because select with id=4 has freed its execution structures after
it has been executed once. The select is uncorrelated, so it did not expect
it would need to be executed for the second time.

Fixed this by adding this logic in
st_select_lex::optimize_unflattened_subqueries():

  If a member of a UNION is correlated, mark all its members as
  correlated, so that they are prepared to be executed multiple times.

don't let Aria create a table that it cannot open

use the correct check. before invoking handler methods we
need to know that the table was opened, not only created.

Do not assume that subquery Item always present.

Removed all dependencies of command line arguments based on positions in
an array (this kind of code should never have been written).
Instead use option names, which are stable.

Reviewer: Sergei Golubchik

Use portable quoting in mtr_add_arg.

- Changed SST scripts to use /usr/bin/env bash instead of
  /bin/bash for better portability.
- Fixed use of mktemp on non-Linux platforms to produce
  temporary file instead of directory.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

(Backport Varun Gupta's patch + edit the commit comment)

Name resolution code produced errors for valid queries with window
functions (but not for queries which used aggregate functions as
window functions).

Name resolution code worked incorrectly, because window function
objects had is_window_func_sum_expr()=false. This was so, because
mark_as_window_func_sum_expr() was only called for aggregate functions
used as window functions.

The fix is to call it for any window function.

Fixed the test to execute only on linux as it depends on unportable sed.

revert 68b3fa88

accessing freed memory.
Before XMLCOL::WriteColumn() Tdbp->Clist gets assigned
a nodelist in

      Clist = RowNode->SelectNodes(g, Colname, Clist);

which is RowNode->Doc->Xop->nodesetval.

In XMLCOL::WriteColumn()

        ValNode = ColNode->SelectSingleNode(g, Xname, Vxnp);

calls LIBXMLDOC::GetNodeList() again, which frees the previous
XPath object Xop and replaces it with a new one.

In this case RowNode->Doc == ColNode->Doc, so Clist->Listp
points to a freed memory now.