Let us use a minimal-size buffer pool to ensure that page flushing
will be slow enough so that LRU eviction cannot be avoided.

Do not print illegal table field names for non-top-level SELECT list,
they will not be refered in any case but create problem for parsing
of printed result.

Problem:
========
This patch addresses two issues.

First, if a CHANGE MASTER command is issued and an error happens
while locating the replica’s relay logs, the logs can be put into an
invalid state where future updates fail and future CHANGE MASTER
calls crash the server. More specifically, right before a replica
purges the relay logs (part of the `CHANGE MASTER TO` logic), the
relay log is temporarily closed with state LOG_TO_BE_OPENED. If the
server errors in-between the temporary log closure and purge, i.e.
during the function find_log_pos, the log should be closed.
MDEV-25284 reveals the log is not properly closed.

Second, upon issuing a RESET SLAVE ALL command, a slave’s GTID
filters are not cleared (DO_DOMAIN_IDS, IGNORE_DOMIAN_IDS,
IGNORE_SERVER_IDS). MySQL had a similar bug report, Bug #18816897,
which fixed this issue to clear IGNORE_SERVER_IDS after issuing
RESET SLAVE ALL in version 5.7.

Solution:
=========

To fix the first problem, the CHANGE MASTER error handling logic was
extended to transition the relay log state to LOG_CLOSED from
LOG_TO_BE_OPENED.

To fix the second problem, the RESET SLAVE ALL logic is extended to
clear the domain_id filter and ignore_server_ids.

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

Schema and table names in a veiw FRM files are:
- in upper case on Linux
- in lower case on Windows

Using the LOWER() function when displaying an FRM file fragment,
to avoid the OS-specific difference.

This happens upon CREATE USER and DROP ROLE.

The underlying problem is that our HASH implementation shuffles elements
around when performing an update or delete. This means that when doing a
scan through the HASH table by index, in search of elements to delete or
update one must restart the scan to make sure nothing is missed if at least
one delete / update happened.

More specifically, what happened in this case:
The hash has 131 element, DROP ROLE removes the element
[119]. Its [119]->next was element [129], so [129] is moved to [119].
Now we need to compact the hash, removing the last element [130]. It
gets one bit off its hash value and becomes element [2]. The existing
element [2] is moved to [129], and old [130] is moved to [2].

We cannot simply move [130] to [129] and make [2]->next=130, it won't
work if [2] is itself in the collision list and doesn't belong in [2].

The handle_grant_struct code assumed that it is safe to continue by only
reexamining the currently modified / deleted element index, but that is
not true.

Missing to delete an element in the hash triggered the assertion in
the test case. DROP ROLE would not clear all necessary role->role or
role->user mappings.

To fix the problem we ensure that the scan is restarted, only if an
element was deleted / updated, similar to how bubble-sort keeps sorting
until it finds no more elements to swap.

MDEV-23408 Wrong result upon query from I_S and further Assertion `!alias_arg || strlen(alias_arg->str) == alias_arg->length' failed with certain connection charset

There were two independent problems which lead to the crash
and to the non-relevant records returned in I_S queries:

- The code in the I_S implementation was not secure
  about values with 0x00 bytes.
  It's fixed by using check_db_name() and check_table_name()
  inside make_table_name_list(), and by adding the test for
  0x00 inside check_table_name().

- The code in Item_string::print() did not convert
  strings without introducers when restoring
  the CREATE VIEW statement from an Item tree.
  This made wrong literals inside the "query" line in the view FRM file
  in cases when the VIEW parse time
  character_set_client!=character_set_connection.
  That's fixed by adding a proper conversion.

  This change also fixed a similar problem in SHOW PROCEDURE CODE -
  the literals were displayed in wrong character set in SP instructions
  in cases when the SP parse time
  character_set_client!=character_set_connection.

but must do that at the end of the statement.
A provide template patch is elaborated also to match
to the upstream fixes of the very same bug.

Add wait_conditions to stabilize

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.

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>

If error_reported is not set upper caller open_table_from_share()
throws error ER_NOT_FORM_FILE itself via open_table_error().

On deadlock transaction is rolled back (and trx->state is cleared) but
SELECT continued the loop because evaluate_join_record() ignored the
error status returned from lower join evaluation. val_int() does not
return error status so it is checked by thd->is_error().

Test case was created by Thirunarayanan Balathandayuthapani
<thiru@mariadb.com>

In commit 3690c549
this test was not adjusted.

This is a documentation-only patch to refine the description of
binary mode for the mariadb client.

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

Note: This patch backports commits 10cd2818 and 1755ea4b from 10.3.

10cd2818:
Problem:- Some binary data is inserted into the table using
Jconnector. When binlog dump of the data is applied using mysql
client it gives syntax error.

Reason:-
After investigating it turns out to be a issue of mysql client not
able to properly handle  \\0 <0 in binary>. In all binary files
where mysql client fails to insert
these 2 bytes are common (0x5c00)

Solution:-
I have changed mysql.cc to include for the possibility that binary
string can have \\0 in it

1755ea4b:
Changes on top of Sachin’s patch. Specifically:
 1) Refined the parsing break condition to only change the parser’s
behavior for parsing strings in binary mode (behavior of \0 outside
of strings is unchanged).
 2) Prefixed binary_zero_insert.test with ‘mysql_’ to more clearly
associate the  purpose of the test.
 3) As the input of the test contains binary zeros (0x5c00),
different text editors can visualize this sequence differently, and
Github would not display it at all. Therefore, the input itself was
consolidated into the test and created out of hex sequences to make
it easier to understand what is happening.
 4) Extended test to validate that the rows which correspond to the
INSERTS with 0x5c00 have the correct binary zero data.

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

If a table has no unique indexes, write set key information will be collected on all columns in the table.
The write set key information has space only for max 3500 bytes for individual column, and if a varchar colummn of such non-primary key table is longer than
 this limit, currently a crash follows.
The fix in this commit, is to truncate key values extracted from such long varhar columns to max 3500 bytes.
This may potentially lead to false positive certification failures for transactions, which operate on separate cluster nodes, and update/insert/delete table rows, which differ only in the part of such long columns after 3500 bytes border.
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

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.

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.

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.

RedHat systems have both files for lsb and init functions.
Old code was written as if/else, so second file (RedHat-specific) was not processed.
So, systemd redirect didn't work, because its logic is described in
RedHat-specific functions file

This reverts commit 30dea459.

This patch is the plan D variant for fixing potetial mutex locking
order exercised by BF aborting and KILL command execution.

In this approach, KILL command is replicated as TOI operation.
This guarantees total isolation for the KILL command execution
in the first node: there is no concurrent replication applying
and no concurrent DDL executing. Therefore there is no risk of
BF aborting to happen in parallel with KILL command execution
either. Potential mutex deadlocks between the different mutex
access paths with KILL command execution and BF aborting cannot
therefore happen.

TOI replication is used, in this approach,  purely as means
to provide isolated KILL command execution in the first node.
KILL command should not (and must not) be applied in secondary
nodes. In this patch, we make this sure by skipping KILL
execution in secondary nodes, in applying phase, where we
bail out if applier thread is trying to execute KILL command.
This is effective, but skipping the applying of KILL command
could happen much earlier as well.

This patch also fixes mutex locking order and unprotected
THD member accesses on bf aborting case. We try to hold
THD::LOCK_thd_data during bf aborting. Only case where it
is not possible is at wsrep_abort_transaction before
call wsrep_innobase_kill_one_trx where we take InnoDB
mutexes first and then THD::LOCK_thd_data.

This will also fix possible race condition during
close_connection and while wsrep is disconnecting
connections.

Added wsrep_bf_kill_debug test case
Reviewed-by: Jan Lindström <jan.lindstrom@mariadb.com>

Revert "MDEV-24873 galera.galera_as_slave_ctas MTR failed:..."

This reverts commit 29bbcac0 and
later commit 5ecaf52d.

At least since commit 055a3334
(MDEV-13564) the undo log truncation in InnoDB did not work correctly.

The main issue is that during the execution of
trx_purge_truncate_history() some pages of the newly truncated
undo tablespace could be discarded.

fsp_try_extend_data_file(): Apply the peculiar rounding of
fil_space_t::size_in_header only to the system tablespace,
whose size can be expressed in megabytes in a configuration parameter.
Other files may freely grow by a number of pages.

fseg_alloc_free_page_low(): Do allow the extension of undo tablespaces,
and mention the file name in the error message.

mtr_t::commit_shrink(): Implement crash-safe shrinking of a tablespace
file. First, durably write the log, then shrink the file, and finally
release the page latches of the rebuilt tablespace. Refactored from
trx_purge_truncate_history().

log_write_and_flush_prepare(), log_write_and_flush(): New functions
to durably write log during mtr_t::commit_shrink().

- Handle stored function conditions correctly, with the same logic as with UDFs.
- When running queries on Spider SE, by default, we do not push down WHERE conditions containing usage of UDFs/stored functions to remote data nodes, unless the user demands (by setting spider_use_pushdown_udf).

SST scripts currently use Linux-specific construction
to create a temporary directory if the path prefix for
that directory is specified by the user. This does not
work with FreeBSD. This commit adds support for FreeBSD.

No separate test required.

btr_defragment_save_defrag_stats_if_needed(): Do not save
defragmentation statistics for temporary tables.
They are exempt of defragmentation anyway
(ha_innobase::optimize() never invokes defragmentation for them),
and the user-visible names are not available inside InnoDB.

Furthermore, InnoDB assumes that temporary tables are never accessed
by other threads than the one that handles the session with which
the temporary table is associated with.

Furthermore, we simplify the test innodb.innodb_defrag_stats
and include a test case that demonstrates that defragmentation
statistics are no longer being saved for temporary tables.

Test case fail to include undo tablespace while waiting for the
encryption thread to encrypt all existing tablespace

Thanks Karl Levik