while it should look at the actual field_type() and use get_date()
or get_time() as appropriate.

test case is in the following commit.

Do not assume that it's always item->field_type() - this is not the case
in temporal comparisons (e.g. when comparing DATETIME column with a TIME
literal).

It's a generic function, not using anything from Arg_comparator.
Make it a static function, not a class method, to be able to use
it later without Arg_comparator

will be used in following commits

reorder items in args[] array. Instead of

  when1,then1,when2,then2,...[,case][,else]

sort them as

  [case,]when1,when2,...,then1,then2,...[,else]

in this case all items used for comparison take a continuous part
of the array and can be aggregated directly. and all items that
can be returned take a continuous part of the array and can be
aggregated directly. Old code had to copy them to a temporary
array before aggreation, and then copy back (thd->change_item_tree)
everything that was changed.

- Fixing the windows failure of unsupported_redo test case.
mariabackup --tables-exclude option only restricts ibd file.

Elaborate shutdown message.

           out of order at retry

The test failures were of two sorts. One is that the number of retries
what the slave thought as a temporary error exceeded
the default value of the slave retry option.
The 2nd issue was an out of order commit by transactions that
were supposed to error out instead.
Both issues are caused by the same reason that the post-temporary-error
retry did not check possibly already existing error status.

This is mended with refining conditions to retry. Specifically, a retrying
worker checks `rpl_parallel_entry::stop_on_error_sub_id` that
a potential failing predecessor could set to its own sub id.
Now should the member be set the retrying follower errors out with
ER_PRIOR_COMMIT_FAILED.

- buf_flush_LRU_list_batch() initializes the count to zero and updates them
correctly.

Problem:
=======
  Mariabackup exits during prepare phase if it encounters
MLOG_INDEX_LOAD redo log record. MLOG_INDEX_LOAD record
informs Mariabackup that the backup cannot be completed based
on the redo log scan, because some information is purposely
omitted due to bulk index creation in ALTER TABLE.

Solution:
========
Detect the MLOG_INDEX_LOAD redo record during backup phase and
exit the mariabackup with the proper error message.

buf_flush_page_cleaner_coordinator(): Signal the worker threads
to exit while waiting for them to exit. Apparently, signals are
sometimes lost, causing shutdown to occasionally hang when
multiple page cleaners (and buffer pool instances) are used,
that is, when innodb_buffer_pool_size is at least 1 GiB.

buf_flush_page_cleaner_close(): Merge with the only caller.

in trans_xa_start.

        test fixed.

In thread caching code, clear THD's warnings before reuse.

There is not current SELECT during assigning SP parameters, do not use it if current_select is empty.

           replicate_events_marked_for_skip=FILTER_ON_MASTER

[Note this is a cherry-pick from 10.2 branch.]

When events of a big transaction are binlogged offsetting over 2GB from
the beginning of the log the semisync master's dump thread
lost such events.
The events were skipped by the Dump thread that found their skipping
status erroneously.

The current fixes make sure the skipping status is computed correctly.
The test verifies them simulating the 2GB offset.

Based on contribution by Daniel Black.

fts_sync(): If the dict_table_t::to_be_dropped flag is set,
do not "goto begin_sync".

Also, clean up the way how dict_index_t::index_fts_syncing
is cleared.

It looks like this regression was introduced by merging
Oracle Bug #24938374 MYSQL CRASHED AFTER LONG WAIT ON DICT OPERATION LOCK
WHILE SYNCING FTS INDEX
https://github.com/mysql/mysql-server/commit/068f8261d4c1e134965383ff974ddf30c0758f51
from MySQL 5.6.38 into MariaDB 10.0.33, 10.1.29, 10.2.10.
The same hang is present in MySQL 5.7.20.

in trans_xa_start.

        THD.transaction.xid_state.xid.rm_error should be cleaned
        as the thread ends.

Don't call handler->position() if the last call to read a row did
not succeed.

fil_space_t::atomic_write_supported: Always set this flag for
TEMPORARY TABLESPACE and during IMPORT TABLESPACE. The page
writes during these operations are by definition not crash-safe
because they are not written to the redo log.

fil_space_t::use_doublewrite(): Determine if doublewrite should
be used.

buf_dblwr_update(): Add assertions, and let the caller check whether
doublewrite buffering is desired.

buf_flush_write_block_low(): Disable the doublewrite buffer for
the temporary tablespace and for IMPORT TABLESPACE.

fil_space_set_imported(), fil_node_open_file(), fil_space_create():
Initialize or revise the space->atomic_write_supported flag.

buf_page_io_complete(), buf_flush_write_complete(): Add the parameter
dblwr, to indicate whether doublewrite was used for writes.

buf_dblwr_sync_datafiles(): Remove an unnecessary flush of
persistent tablespaces when flushing temporary tablespaces.
(Move the call to buf_dblwr_flush_buffered_writes().)

buf_flush_init_for_writing(): Remove the parameter skip_checksum.

fsp_init_file_page_low(): Always initialize the page.

The crash occurs when inserting into, updating or deleting from Spider system
tables.  These operations do not go through the normal insert, update or
delete logic, so binary logging of the row is not properly set up and leads
to the crash.

The fix for this problem uses the same strategy as is used for the servers
system table that contains entries for the servers created with CREATE SERVER.
Binary logging is now temporarily disabled on insert, update and delete
operations on Spider system tables.

Author:
  Jacob Mathew.

Reviewer:
  Kentoku Shiba.

MDEV-14648 Restore fix for MySQL BUG#39053 - UNINSTALL PLUGIN does not allow the storage engine to cleanup open connections

ha_close_connection(): Do invoke the method also for plugins
for which UNINSTALL PLUGIN was deferred due to open connections.

There were some differences on MariaDB compared with MySQL.
Fix these differences.

InnoDB in Debian uses utf8mb4 as default character set since
version 10.0.20-2. This leads to major pain due to keys longer
than 767 bytes.

MariaDB 10.2 (and MySQL 5.7) introduced the setting
innodb_default_row_format that is DYNAMIC by default. These
versions also changed the default values of the parameters
innodb_large_prefix=ON and innodb_file_format=Barracuda.
This would allow longer column index prefixes to be created.
The original purpose of these parameters was to allow InnoDB
to be downgraded to MySQL 5.1, which is long out of support.

Every InnoDB version since MySQL 5.5 does support operation
with the relaxed limits.

We backport the parameter innodb_default_row_format to
MariaDB 10.1, but we will keep its default value at COMPACT.
This allows MariaDB 10.1 to be configured so that CREATE TABLE
is less likely to encounter a problem with the limitation:

	loose_innodb_large_prefix=ON
	loose_innodb_default_row_format=DYNAMIC

(Note that the setting innodb_large_prefix was deprecated in
MariaDB 10.2 and removed in MariaDB 10.3.)

The only observable difference in the behaviour with the default
settings should be that ROW_FORMAT=DYNAMIC tables can be created
both in the system tablespace and in .ibd files, no matter what
innodb_file_format has been assigned to. Unlike MariaDB 10.2,
we are not changing the default value of innodb_file_format,
so ROW_FORMAT=COMPRESSED tables cannot be created without
changing the parameter.

fix 50359719
don't rely on any specific engine checking order