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.

Some users and some scripts (for example, mysqld_multi.sh) use special
option groups with names like [mysqld1], [mysqld2], ..., [mysqldN].

But SST scripts can't currently fully support these option groups.
The only option group-related value it gets from the server is
--defaults-group-suffix, if that option was set for mysqld when
the server was started.

However, the SST scripts does not get told by the server to read
these option groups, so this means that the SST script will fail
to read options like innodb-data-home-dir when it is in a option
group like [mysqld1]...[mysqldN].

Moreover, SST scripts ignore many parameters that can be passed
to them explicitly and cannot transfer them further, for example,
to the input of mariabackup utility. Ideally, we want to transfer
all the parameters of the original mysqld call to utilities such
as mariabackup, however the SST script does not receive these
parameters from the server and therefore cannot transfer them to
mariabackup.

To correct these shortcomings, we need to transfer to the scripts
all of the parameters of the original mysqld call, and in the SST
scripts themselves provide for the transfer all of these parameters
to utilities such as mariabackup. To prevent these parameters from
mixing with the script's own parameters, they should be transferred
to SST script after the special option "--mysqld-args", followed by
the string argument with the original parameters, as it received by
the mysqld call at the time of launch (further all these parameters
will be passed to mariabackup, for example).

In addition, the SST scripts themselves must be refined so that
they can read the parameters from the user-selected group, not just
from the global mysqld configuration group. And also so that they
can receive the parameters (which important for their work) as
command-line arguments.

This patch corrects the fix of the patch for mdev-19421 that resolved
the problem of parsing some embedded join expressions such as
  t1 join t2 left join t3 on t2.a=t3.a on t1.a=t2.a.
Yet the patch contained a bug that prevented proper context analysis
of the queries where such expressions were used together with comma
separated table references in from clauses.

Update test results.

MDEV-15955 Assertion `field_types == 0 || field_types[field_pos] == MYSQL_TYPE_LONGLONG' failed in Protocol_text::store_longlong

There were two problems:

(1) If user wanted same time zone information on all nodes in the Galera
cluster all updates were not replicated as time zone information was
stored on MyISAM tables. This is fixed on Galera by altering time zone
tables to InnoDB while they are modified.

(2) If user wanted different time zone information to nodes in the Galera
cluster TRUNCATE TABLE for time zone tables was replicated by Galera
destroying time zone information from other nodes. This is fixed
on Galera by introducing new option for mysql_tzinfo_to_sql_symlink
tool --skip-write-binlog to disable Galera replication while
time zone tables are modified.

Changes to be committed:
	modified:   mysql-test/r/mysql_tzinfo_to_sql_symlink.result
	modified:   mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink.result
	new file:   mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink_skip.result
	new file:   mysql-test/suite/wsrep/t/mysql_tzinfo_to_sql_symlink_skip.test
	modified:   sql/tztime.cc

When discounting selectivity of ref access, don't discount the
selectivity we've already discounted for range access.

The 10.1 version of the fix. Will need to adjust condition filtering
test results in 10.4

A histogram size that is odd in size with DOUBLE precision will leave the last
byte unwritten. When collecting histograms, this causes the last byte to
be uninitialized in the record. memset the buffer to 0 first to make
sure this does not happen.

Skip the test on big-endian systems.
In MariaDB Server 10.0 and 10.1 (as well as MySQL 5.6),
the implementation of innodb_checksum_algorithm=crc32
wrongly assumes little-endian byte order.

Fix incorrect else that should have been else if.