The test main.index_merge_innodb is taking very much time,
especially on later versions (10.2 and 10.3).

Some of this could be attributed to the use of INSERT...SELECT,
which is time-consumingly creating explicit record locks in InnoDB
for the locking read in the SELECT part.

In 10.3 and later, some slowness can be attributed to MDEV-12288,
which makes the InnoDB purge thread spend time to reset transaction
identifiers in the inserted records. If we prevent purge from
running before all tables are dropped, the test seems to be
10% faster on an unoptimized debug build on 10.5. (A proper fix
would be to implement MDEV-515 and stop writing row-level undo log
records for inserts into an empty table or partition.)

At the same time, it should not hurt to make main.index_merge_myisam
to use the sequence engine. Not only could it be a little faster,
but the test would be slightly more readable.

The function was declared but not defined in
commit 9d6d1902

             read_statistics_for_tables_if_needed

Regression after 279a907f, read_statistics_for_tables_if_needed() was
called after open_normal_and_derived_tables() failure.

Fixed by moving read_statistics_for_tables() call to a branch of
get_schema_stat_record() where result of open_normal_and_derived_tables()
is checked.

Removed THD::force_read_stats, added read_statistics_for_tables() instead.
Simplified away statistics_for_command_is_needed().

Moved EITS allocation inside read_statistics_for_tables_if_needed().
Removed redundant is_safe argument.

MDEV-20645: Replication consistency is broken as workers miss the error notification from an earlier failed group.

Analysis:
========
In general if there are three groups.
1 - Inserts 32 which fails due to local entry '32' on slave.
2 - Inserts 33
3 - Inserts 34

Each group considers itself as a waiter and it waits for prior group 'waitee'.
This is done in 'register_wait_for_prior_event_group_commit'. If there is no
other parallel group being scheduled then no waitee will be there.

Let us assume 3 groups are being scheduled in parallel.

3-> waits for 2-> waits for->1

'1' upon completion it checks is there any registered subsequent waiter. If
so it wakes up the subsequent waiter with its execution status. This execution
status is stored in wakeup_error.

If '1' failed then it sends corresponding wakeup_error to 2. Then '2' aborts
and it propagates error to '3'.  So all further commits are aborted.  This
mechanism works only when all transactions reach a stage where they are
waiting for their prior commit to complete.

In case of optimistic following scenario occurs.

1,2,3 are scheduled in parallel.

3 - Reaches group_commit_code waits for 2 to complete.
1 - errors out sets stop_on_error_sub_id=1.

When a group execution results in error its corresponding sub_id is set to
'stop_on_error_sub_id'. Any new groups queued for execution will check if
their sub_id is > stop_on_error_sub_id.  If it is true their execution will be
skipped as prior group execution failed.  'skip_event_group=1' will be set.
Since the execution of SQL thread is about to stop we just skip execution of
all the following event groups.  We still do all the normal waiting and wakeup
processing between the event groups as a simple way to ensure that everything
is stopped and cleaned up correctly.

Upon error '1' transaction checks for registered waiters. Since no one is
there it simply goes away.

2 - Starts the execution. It checks do I have a waitee.

Since wait_commit_sub_id == entry->last_committed_sub_id no waitee is set.

Secondly: 'entry->stop_on_error_sub_id' is set by '1'st execution.  Now
'handle_parallel_thread' code checks if the current group 'sub_id' is greater
than the 'sub_id' set within 'stop_on_error_sub_id'.

Since the above is true 'skip_event_group=true' is set.  Simply call
'wait_for_prior_commit' to wakeup all waiters.  Group '2' didn't had any
waitee and its execution is skipped.  Hence its wakeup_error=0.It sends a
positive wakeup signal to '3'. Which commits. This results in a missed
transaction. i.e 33 is missed and 34 is committed.

Fix:
===
When a worker learns that an earlier transaction execution has failed, and it
should not proceed for further execution, it should mark its own execution
status as failed so that it alerts its followers to abort as well.

chkconfig --add and --del [might] invoke /sbin/insserv
and even if chkconfig exists, insserv might not (SLES15).

Ignore chkconfig --del errors - it's a "best effort" cleanup anyway

A syntax error in the mysqld_multi.sh script has been fixed
here + a "--defaults-group-suffix" option has been moved to
the top of the mysqld options list.

Eliminate one InnoDB table with 128*16384 rows, and use
the sequence engine instead. Also, run everything in a single
transaction, to prevent purge from running concurrently
unnecessarily. (Starting with MariaDB Server 10.3, purge would
reset the DB_TRX_ID after INSERT.)

MDEV-20495 Assertion `precision > 0' failed in decimal_bin_size upon CREATE .. SELECT with zerofilled decimal

Also fixes:

MDEV-20560 Assertion `precision > 0' failed in decimal_bin_size upon SELECT with MOD short unsigned decimal

Changing the way how Item_func_mod calculates its max_length.
It now uses decimal_precision(), decimal_scale() and unsigned_flag
of its arguments, like all other Item_num_op descendants do.

In the function test_if_cheaper_ordering we make a decision if using an index is better than
using filesort for ordering. If we chose to do range access then in test_quick_select we
should make sure that cost for table scan is set to DBL_MAX so that it is not picked.

The unit files made systemd print:

systemd[1]: Started MariaDB 10.3.13 database server (multi-instance).

Let's add the instance name, so starting mariadb@foo.service
makes it print:

systemd[1]: Started MariaDB 10.3.13 database server (multi-instance foo).

"--defaults-group-suffix" must be be given as the first argument on the command-line of mysqld

mysqld_safe --dry-run needs to either call exit or return, depending if
it is being sourced or not, otherise return can lead to the error:

return: can only `return' from a function or sourced script

The original fix suggestion was proposed by FaramosCZ <mschorm@centrum.cz>

* Change the comments in mysql-log-rotate.sh to refer to mysqld, not mysqld_safe
  as that's what most distros are using.
* Change err-log to log-error as err-log is no longer valid.
* Convert tab to space for consistency.

Fix build error with newer cmake

Fixes the following build error:

CMake Error at cmake/os/Linux.cmake:29 (STRING):
STRING sub-command REPLACE requires at least four arguments.
Call Stack (most recent call first):
CMakeLists.txt:101 (INCLUDE)

CMake Error at cmake/os/Linux.cmake:29 (STRING):
STRING sub-command REPLACE requires at least four arguments.
Call Stack (most recent call first):
CMakeLists.txt:101 (INCLUDE)

The error happens when CMAKE_SHARED_LINKER_{LANG}_FLAGS is not set.
Force the variable to be set to "" as input to prevent this.
Signed-off-by: Ryan Coe <bluemrp9@gmail.com>
Signed-off-by: Vicențiu Ciorbaru <vicentiu@mariadb.org>

Fixes bug introduced in commit 54150029.

Using script run-time filename does not always work. One cannot assume
that the filename is always the same as there might be temporary file
names used by dpkg in certain situations. See Debian #920415.

The same fix has been successfully in use in Debian official packages
since February 2019:
https://salsa.debian.org/mariadb-team/mariadb-10.3/commit/6440c0d6e75

Problem:
=======
  During dropping of fts index, InnoDB waits for fts_optimize_remove_table()
and it holds dict_sys->mutex and dict_operaiton_lock even though the
table id is not present in the queue. But fts_optimize_thread does wait
for dict_sys->mutex to process the unrelated table id from the slot.

Solution:
========
  Whenever table is added to fts_optimize_wq, update the fts_status
of in-memory fts subsystem to TABLE_IN_QUEUE. Whenever drop index
wants to remove table from the queue, it can check the fts_status
to decide whether it should send the MSG_DELETE_TABLE to the queue.

Removed the following functions because these are all deadcode.
dict_table_wait_for_bg_threads_to_exit(),
fts_wait_for_background_thread_to_start(),fts_start_shutdown(), fts_shudown().

- There is no need to add the table in fts_optimize_wq if there is
no fts indexes associated with it.

Adjusted test results.

           selectivity values fails

After having set the assertion that checks validity of selectivity values
returned by the function table_cond_selectivity() a test case from
order_by.tesst failed. The failure occurred because range optimizer could
return as an estimate of the cardinality of the ranges built for an index
a number exceeding the total number of records in the table.

The second bug is more subtle. It may happen when there are several
indexes with same prefix defined on the first joined table t accessed by
a constant ref access. In this case the range optimizer estimates the
number of accessed records of t for each usable index and these
estimates can be different. Only the first of these estimates is taken
into account when the selectivity of the ref access is calculated.
However the optimizer later can choose a different index that provides
a different estimate. The function table_condition_selectivity() could use
this estimate to discount the selectivity of the ref access. This could
lead to an selectivity value returned by this function that was greater
that 1.

Null merge the MDEV-14383 fix; it affects 5.5 only.

InnoDB intentionally (it's a documented behavior) ignores changing of
DATA DIRECTORY and INDEX DIRECTORY for partitions. Though we should
issue warning when this happens.

Fix the test case.

Test fixed to be deterministic.

don't run tokudb tests under tcmalloc,
this is not a supported combination.

Improved handling of subdirectories in the xtrabackup-v2 SST scripts (similar to MDEV-18863) for more predictable test results (related to xtrabackup-v2 SST)

Also fixes:

MDEV-20431 GREATEST(int_col,date_col) returns wrong results in a view

After applying MDEV-18863, in some test configurations, SST
may fails due to duplication of some parameters (in particular
"--port") in the main part of the command line and after
"--mysqld-args", as well as due to incorrect interpretation
of the parameter "--port" passed after "--mysqld-args" when
the SST script is invoked without explicitly specifying a port
for SST. In addition, it is necessary to correctly handle spaces,
quotation marks and special characters when copying original
arguments from the argv[] array to a new command line (after
"--mysqld-args"). This patch resolves these shortcomings.

Analysis:
========
As part of BUG#28642318 fix, two new test cases were added. The first test
case tests a scenario where two sessions are present, in which the first
session has a regular table named 't1' and another session has a temporary
table named 't1'. Test executes a DELETE statement on regular table. These
statements are captured from binary log and replayed back on new client
connection to prove that DELETE statement is applied successfully. Note that
the binlog contains only CREATE TEMPORARY TABLE part hence a temporary table
gets created in new connection. This replaying logic is implemented by using
'--exec $MYSQL' command. If the new connection gets disconnected within the
scope of first test case the test passes, i.e the temporary table gets dropped
as part thread cleanup. But on slow platforms the connection gets closed at
the time of execution of test case 2. When the temporary table is dropped as
part thread cleanup a "DROP TEMPORARY TABLE t1" is written into the binary
log. In test case two the same sessions continue to exist and and table names
are reused to test a new bug scenario. The additional "DROP TEMPORARY TABLE"
command drops second test specific tables which results in "Unknown table"
error.

Fix:
====
Rename the second case specific table to 't2'. Even if the close connection
from test case one happens later the drop command with has
'DROP /*!40005 TEMPORARY */ TABLE IF EXISTS `t1`' will not result in an error.

Some code was duplicated near the start of the function,
only for InnoDB, not XtraDB. This was noticed by
comparing the InnoDB between MariaDB and MySQL.

For the Sphinx storage engine, this is a functional change (bug fix):
we will ensure that the message buffer is always NUL-terminated.