Before killing the server, we must issue FLUSH TABLES in order
to cleanly close any MyISAM system tables, to avoid warnings about
them when restarting.

```----
MySQL abnormally exits on KILL command.

Fix
```

The abnormal exit has been fixed.

RB: 20971, 21129, 21237

For partitioned table, ensure that the AUTO_INCREMENT values will
be assigned from the same sequence. This is based on the following
change in MySQL 5.6.44:

commit aaba359c13d9200747a609730dafafc3b63cd4d6
Author: Rahul Malik <rahul.m.malik@oracle.com>
Date:   Mon Feb 4 13:31:41 2019 +0530

    Bug#28573894 ALTER PARTITIONED TABLE ADD AUTO_INCREMENT DIFF RESULT DEPENDING ON ALGORITHM

    Problem:
    When a partition table is in-place altered to add an auto-increment column,
    then its values are starting over for each partition.

    Analysis:
    In the case of in-place alter, InnoDB is creating a new sequence object
    for each partition. It is default initialized. So auto-increment columns
    start over for each partition.

    Fix:
    Assign old sequence of the partition to the sequence of next partition
    so it won't start over.

    RB#21148
    Reviewed by Bin Su <bin.x.su@oracle.com>

Correctly document the usage of m_max_value. Remove the const
qualifier, so that the implicit assignment operator can be used.
Make all members of ib_sequence private, and add an accessor
member function max_value().

PROBLEM
 =======
An add index doesn't update index length stats in information schema
TABLES table.

FIX
 ===
Update the dict_table_t variable with index length stats that is
actually calculated post alter . As this variable is used to populated
the information schema index length statistics.

Reviewed by: Bin su<bin.x.su@oracle.com>
RB: 21277

Field_bit for BIT(20) uses 2 full bytes in the record,
with additional 4 uneven bits in the "null bit area".

Field::set_default() called from Field_bit::set_default() erroneously
copied 3 bytes instead of 2 bytes from the record with default values.

Changing Field::set_default() to copy pack_length_in_rec() bytes
instead of pack_length() bytes.

In debug builds, this setting is allowed to be turned off temporarily after it was
turned on during startup. Howewer memory garbage also caused it to be accidentally
turned on when it was disabled at startup.

group concat tree is allocated in a memroot, so the only way to free
memory is to copy a part of the tree into a new memroot.

track the accumilated length of the result, and when it crosses
the threshold  - copy the result into a new tree, free the old one.

do it only for items that inherit from Item_result_field*

move per-object TREE::null_element to be one global
static null_element.

Closes #1262

add a new option --pam-windbind-workaround for a pam plugin to
work around pam_winbind unconditional username lowercasing

only use SHOW TRIGGERS on old (< 5.1.21) servers, otherwise
always use SHOW CREATE TRIGGER and don't fallback.

create mysql and test databases with SQL, not mkdir.

Take into account ps-protocol states.
Note, repace_regex was redundant, because Host column was replaced anyway

Apply dbart's patch to set epoch for all ubuntu releases starting
from bionic. Not only for bionic.

This works for Debian too (VERNUM=unstable, etc).

MDEV-15907 ASAN heap-use-after-free in strnmov / .. / fill_effective_table_privileges on concurrent GRANT and CREATE VIEW

rename a test file.

Closes #1253

This patch fixes an invalid read in fill_effective_table_privileges
triggered by a grant_version increase between a PREPARE for a
statement creating a view from I_S and EXECUTE.
A tmp table was created and free'd while preparing the statement,
TABLE_LIST::table_name was set to point to the tmp table
TABLE_SHARE::table_name which no longer existed after preparing was
done.
The grant version increase made fill_effective_table_privileges
called during EXECUTE to try fetch the updated grant info and
this is where the dangling table name was used.

triggers are opened and tables used in triggers are prelocked in
open_tables(). But multi-update can detect what tables will actually
be updated only later, after all main tables are opened.

Meaning, if a table is used in multi-update, but is not actually updated,
its on-update treggers will be opened and tables will be prelocked,
even if it's unnecessary. This can cause more tables to be
write-locked than needed, causing read_only errors, privilege errors
and lock waits.

Fix: don't open/prelock triggers unless table->updating is true.
In multi-update after setting table->updating=true, do a second
open_tables() for newly added tables, if any.

it always required UPDATE privilege on views, not being able to detect
when a views was not actually updated in multi-update.

fix: instead of marking all tables as "updating" by default,
only set "updating" on tables that will actually be updated
by multi-update. And mark the view "updating" if any of the
view's tables is.

privilege tables can never be views or temporary tables,
don't even try to open them, if they are.

MDEV-18923 Assertion `!lex_string_cmp(system_charset_info, fk_info->referenced_table, &table->s->table_name)' failed in fk_truncate_illegal_if_parent

don't assert the correctness of FK constraints, as it can be
broken under `SET FOREIGN_KEY_CHECKS= OFF`

InnoDB could return the same list again and again if the buffer
passed to trx_recover_for_mysql() is smaller than the number of
transactions that InnoDB recovered in XA PREPARE state.

We introduce the transaction state TRX_PREPARED_RECOVERED, which
is like TRX_PREPARED, but will be set during trx_recover_for_mysql()
so that each transaction will only be returned once.

Because init_server_components() is invoking ha_recover() twice,
we must reset the state of the transactions back to TRX_PREPARED
after returning the complete list, so that repeated traversals
will see the complete list again, instead of seeing an empty list.
Without this tweak, the test main.tc_heuristic_recover would hang
in MariaDB 10.1.

Problem:
========
The mysqlbinlog tool is leaking memory, causing failures in various tests when
compiling and testing with AddressSanitizer or LeakSanitizer like this:

cmake -DCMAKE_BUILD_TYPE=Debug -DWITH_ASAN:BOOL=ON /path/to/source
make -j$(nproc)
cd mysql-test
ASAN_OPTIONS=abort_on_error=1 ./mtr --parallel=auto rpl.rpl_row_mysqlbinlog

CURRENT_TEST: rpl.rpl_row_mysqlbinlog

Direct leak of 112 byte(s) in 1 object(s) allocated from:
#0 0x4eff87 in __interceptor_malloc (/dev/shm/5.5/client/mysqlbinlog+0x4eff87)
#1 0x60eaab in my_malloc /mariadb/5.5/mysys/my_malloc.c:41:10
#2 0x5300dd in Log_event::read_log_event(char const*, unsigned int, char const**,
   Format_description_log_event const*, char) /mariadb/5.5/sql/log_event.cc:1568:
#3 0x564a9c in dump_remote_log_entries(st_print_event_info*, char const*)
/mariadb/5.5/client/mysqlbinlog.cc:1978:17

Analysis:
========
'mysqlbinlog' tool is being used to read binary log events from a remote server.
While reading binary log, if a fake rotate event is found following actions are
taken.

If 'to-last-log' option is specified, then fake rotate event is processed.
In the absence of 'to-last-log' skip the fake rotate event.

In this skipped case the fake rotate event object is not getting cleaned up
resulting in memory leak.

Fix:
===
Cleanup the fake rotate event.

This issues is already fixed in MariaDB 10.0.23 and higher versions as part of
commit c3018b0f