InnoDB was writing unnecessary information to the
update undo log records. Most notably, if an indexed column is updated,
the old value of the column would be logged twice: first as part of
the update vector, and then another time because it is an indexed column.

Because the InnoDB undo log record must fit in a single page,
this would cause unnecessary failure of certain updates.

Even after this fix, InnoDB still seems to be unnecessarily logging
indexed column values for non-updated columns. It seems that non-updated
secondary index columns only need to be logged when a PRIMARY KEY
column is updated. To reduce risk, we are not fixing this remaining flaw
in GA versions.

trx_undo_page_report_modify(): Log updated indexed columns only once.

based on:

commit f7316aa0
Author: Ajo Robert <ajo.robert@oracle.com>
Date:   Thu Aug 24 17:03:21 2017 +0530

    Bug#26361149  MYSQL SERVER CRASHES AT: COL IN(IFNULL(CONST,
                           COL), NAME_CONST('NAME', NULL))

    Backport of Bug#19143243 fix.

    NAME_CONST item can return NULL_ITEM type in case of incorrect arguments.
    NULL_ITEM has special processing in Item_func_in function.
    In Item_func_in::fix_length_and_dec an array of possible comparators is
    created. Since NAME_CONST function has NULL_ITEM type, corresponding
    array element is empty. Then NAME_CONST is wrapped to ITEM_CACHE.
    ITEM_CACHE can not return proper type(NULL_ITEM) in Item_func_in::val_int(),
    so the NULL_ITEM is attempted compared with an empty comparator.
    The fix is to disable the caching of Item_name_const item.

Partition wasn't setting HA_OPTION_PACK_RECORD on ALTER TABLE
if the row format was PAGE.

(so one bit in the null bitmap was reserved for a deleted bit -
see make_empty_rec - and all actual null bits were one off)

if it's a DROP TABLE, we cannot detect whether a table is
temporary by looking in thd->temporary_tables - because the
table might simply not exist at all.

backport ce6c0e58

MDEV-8960: Can't refer the same column twice in one ALTER TABLE

Problem was that if column was created in alter table when
it was refered again it was not tried to find from list
of current columns.

mysql_prepare_alter_table:
  There is two cases
    (1) If alter table adds a new column and then later alter
        changes the field definition, there was no check from
	list of new columns, instead an incorrect error was given.
    (2) If alter table adds a new column and then later alter
        changes the default, there was no check from list of
	new columns, instead an incorrect error was given.

always search in compile-time specified paths
INSTALL_BINDIR, INSTALL_SBINDIR, INSTALL_MYSQLSHAREDIR. User
can set them to arbitrary values, it's not enough to search only
in their usual values of bin, sbin and libexec, share and share/mysql.

1. detect resolveip location, don' assume it's in $basedir/bin
2. don't guess $scriptdir to (incorrectly) construct the $0 path
3. rename find_in_basedir -> find_in_dirs, don't prepend $basedir
   automatically. This allows to use identical path lists in
   find_in_dirs and in cannot_find_file.
4. move search path lists to CMakeLists.txt to avoid specifying the
   same path list twice (in find_in_dirs and in cannot_find_file).

mostly caused by -Wimplicit-fallthrough

MDEV-9619: Assertion `null_ref_table' failed in virtual table_map Item_direct_view_ref::used_tables() const on 2nd execution of PS

Refer left expression indirectly in case it changes from execution to execution.

For each SELECT the list sj_nests is built by the
function simplify_joins() when scanning different
join nests. This function may be called several
times for the same join nest. That's why before
adding a new member to sj_nests it is necessary
to check if it's already in the list.
The code of simplify_joins() lacked this check and
as a result it could cause memory overwright for
some queries.

             in buildbot

Removed plugin_array_version: it is being checked without mutex protection and
thus is prone to data race and race conditions. In effect plugins are not
protected from concurrent destruction.

Removed state_mask inversion: doesn't seem to make any sense.

When collecting local plugins list, only add plugins that match state_mask.

Use plugin ref counting to protect against concurrent plugin destruction.

MDEV-9208: Function->Function->View = Mysqld segfault (Server crashes in Dependency_marker::visit_field on 2nd execution with merged subquery)

Prevent crossing name resolution border in finding item tables.

MDEV-13595: mariadb-10.2.8/storage/maria/ma_loghandler.c:2730]: (style) Array index 'chunk_offset' is used before limits check.

In fact just a cosmetic fix, code was safe because translog_get_first_chunk_offset return offsets inside the page.

btr_cur_pessimistic_delete(): Discard a possible record lock also in
the case when the record was the only one in the page. Failure to
do this would corrupt the record lock data structures in a partial
rollback (ROLLBACK TO SAVEPOINT or rolling back a row operation due
to some error, such as a duplicate key in a unique secondary index).

        The MySQL 5.6 doesn't always send the MYSQL_AUDIT_GENERAL_LOG
        notification. So we have to suppress the log_current_query()
        in this case.

No commit message

DESCRIPTION:
===========
The bug is related to incorrect parsing of SQL queries
when typed in on the CLI. The incorrect parsing can
result in unexpected results.

ANALYSIS:
========
The scenarios mainly happens for identifier names
with a typical combination of backslashes and backticks.
The incorrect parsing can either result in executing
additional queries or can result in query truncation.
This can impact mysqldump as well.

FIX:
===
The fix makes sure that such identifier names are
correctly parsed and a proper query is sent to the
server for execution.

(cherry picked from commit 31a372aa1c2b93dc75267d1f05a7f7fca6080dc0)

                       COL), NAME_CONST('NAME', NULL))

Backport of Bug#19143243 fix.

NAME_CONST item can return NULL_ITEM type in case of incorrect arguments.
NULL_ITEM has special processing in Item_func_in function.
In Item_func_in::fix_length_and_dec an array of possible comparators is
created. Since NAME_CONST function has NULL_ITEM type, corresponding
array element is empty. Then NAME_CONST is wrapped to ITEM_CACHE.
ITEM_CACHE can not return proper type(NULL_ITEM) in Item_func_in::val_int(),
so the NULL_ITEM is attempted compared with an empty comparator.
The fix is to disable the caching of Item_name_const item.

              LAST BYTE ONLY (YASSL)


Description:- TLS cipher negociation happens incorrectly
leading to the use of a different

Analysis:- YaSSL based MySQL server will compare only the
last byte of each cipher sent in the Client Hello message.
This can cause TLS connections to fail, due to the server
picking a cipher which the client doesn't actually support.

Fix:- A fix for detecting cipher suites with non leading
zeros is included as YaSSL only supports cipher suites with
leading zeros.

Analysis
========
CREATE TABLE of InnoDB table with a partition name
which exceeds the path limit can cause the server
to exit.

During the preparation of the partition name,
there was no check to identify whether the complete
path name for partition exceeds the max supported
path length, causing the server to exit during
subsequent processing.

Fix
===
During the preparation of partition name, check and report
an error if the partition path name exceeds the maximum path
name limit.

This is a 5.5 patch.

Backport from 5.7 to 5.5 Field_set::val_str()
should return String("", 0, cs) rather than String(NULL, 0, cs)

Problem & Analysis: Slave's Receiver thread, Applier thread and worker
    threads are created with LOCAL-INFILE option enabled. As the document
    says https://dev.mysql.com/doc/refman/5.7/en/load-data-local.html,
    there are some issues if a thread enables local infile.
    This flag should be enabled with care. But for the above mentioned
    internal threads, server is enabling it at the time of creation.

Fix: Further analysis on the code shows that none of threads really
    need this flag to be enabled at any time as Slave never executes
    "LOAD DATA LOCAL INFILE" after reading it from Relay log.
    Applier thread removes "LOCAL" before start executing the query.

MDEV-11240: Server crashes in check_view_single_update or Assertion `derived->table' failed in mysql_derived_merge_for_insert

Before "merge" view shoud be inited to maintaing transitive attributes like "multitable".

The test wasn't restoring log_output properly.
Also added output of query_time in case of wrong result, to
investigate the failure described in MDEV-13408

MDEV-13458: Wrong result for aggregate function with distinct clause when the value for tmp_table_size is small

Fixed by making sure that the sort buffer would have atleast MERGEBUFF2 keys.
Also fixed MDEV-13457 by making sure that an empty tree is never dumped to the disk

Issue:
------
Running MTR with the --no-reorder option by specifying test cases on the
command line, without prefixing the suite name results in an error saying the
test case was not found in the main suite. This is because MTR looks for the
test case only in the main suite, and no other suites.

Fix:
----
The fix involves searching for the test in every suite if only the test name
is specified. This back-ports two bug fixes: Bug#24967869 and Bug#24365783
Reviewed-by: Pavan Naik <pavan.naik@oracle.com>
RB: 16812

Problem
rpl.rpl_mdev-11092 fails in buildbot because after starting slave in
wait_for_slave_sql_error_and_skip.inc slave is started but there may be
chances that we have not skipped the last error and Last_SQL_Errno is
still not zero untill the end of rpl_end.inc , which will compare
Last_SQL_Errno to 0. So in this this case rpl_mdev-11092 fails.

Solution
After starting slave in wait_for_slave_sql_error_and_skip.inc we will wait for
Last_SQL_Errno to become 0.