The loop in read_xml_field(), unlike the same loop in read_sep_field(),
cannot end with item<>NULL, as it does not have any "break" statements.
The entire block "if (item) {...}" was a dead code.

The fixes for these bugs:

Bug#27586 Wrong autoinc value assigned by LOAD DATA in the NO_AUTO_VALUE_ON_ZERO mode
Bug#22372 Disable spatial key, load data, enable spatial key, crashes table

fixed only LOAD DATA INFILE, but did not fix LOAD XML INFILE.

This patch does for LOAD XML FILE what patches for Bug#27586 and Bug#22372
earlier did for LOAD DATA INFILE.

1. Fixing the auto_increment problem:
   a. table->auto_increment_field_not_null is not set to TRUE
      anymore when a column does not have a corresponding XML tag.
   b. Adding "table->auto_increment_field_not_null= false"
      in the end of read_xml_field().
   These two changes resemble the patch for Bug#27586.

2. Fixing the GEOMETRY problem:
   The result for "reset()" was not tested for errors in read_xml_field(),
   which made it possible for empty string to sneak into a "GEOMETRY NOT NULL"
   column when this column does not have a corresponding XML tag with data.
   After this patch the result of reset() is tested and and an error is
   returned in such cases.
   This change effectively resembles the patch for Bug#22372

3. Spliting the code into a new virtual method Field::load_data_set_null().

   Rationale:
   a. To avoid duplicate code in read_sep_field() and read_xml_field():
      Changes #1 and #2 made the code handling NULL values for Field
      exactly the same in read_sep_field() and read_xml_field().

  b. To avoid tests for field_type(), which is not friendly to
     upcoming data type plugins.
     This change makes it possible for data type plugins
     to implement their own special way for handling NULL values in LOAD DATA
     by overriding Field_xxx::load_data_set_null(),
     like Field_geom and Field_timestamp do.

If connection was not blocked, the 'db' was not properly reset
This bug didn't affect information_schema

Part #2: Take into accont the fact that three binary collations that
we handle are technically NOPAD collations

Disallow use of NOPAD collations in indexed columns.

When the transaction isolation level is SERIALIZABLE, or when
a locking read is performed in the REPEATABLE READ isolation level,
InnoDB must lock delete-marked records in order to prevent another
transaction from inserting something.

However, at READ UNCOMMITTED or READ COMMITTED isolation level or
when the parameter innodb_locks_unsafe_for_binlog is set, the
repeatability of the reads does not matter, and there is no need
to lock any records.

row_search_mvcc(): Skip locks on delete-marked committed records upfront,
instead of invoking row_unlock_for_mysql() afterwards. The unlocking
never worked for secondary index records.

dict_stats_rename_table(): After DB_LOCK_WAIT_TIMEOUT
or DB_DUPLICATE_KEY, reset the trx->error_state before retrying.
Also, properly treat DB_DEADLOCK as a hard error.

Part #2: Adjust other parts of testsuite to take into account
that RocksDB files are in "#rocksdb" now.

Part2: make MyRocks add its directory into @@ignore_db_dirs when starting.

This is necessary because apparently not everybody are using plugin's my.cnf
So load ha_rocksdb.{so,dll} manually and then hit MDEV-12451, MDEV-14461
etc.

Rename  Use '#rocksdb' instead of '.rocksdb' as subdirectory for RocksDB
datadir.

MDEV-14614 InnoDB: Failing assertion: trx->error_state == DB_SUCCESS or lock wait timeout upon saving statistics

The assertion failure was caused by
MDEV-14511 Use fewer transactions for updating InnoDB persistent statistics

We are reusing a transaction object after commit, and sometimes,
even after a successful operation, the trx_t::error_state may be
something else than DB_SUCCESS. Reset the field when needed.

Before MySQL 5.7 or MariaDB 10.2.2, there used to be some
magic InnoDB table names that would assign some InnoDB flags
on CREATE TABLE or DROP TABLE.

Starting with MySQL 5.7 (or MariaDB 10.2.2) InnoDB no longer contains
the "table monitor" or "tablespace monitor". The conditions on
srv_print_innodb_tablespace_monitor, srv_print_innodb_table_monitor
never hold. So, the code was dead.

Also, remove a bogus reference to dict_print(), which used to implement
the InnoDB table monitor.

fil_get_space_names(): Remove.

fts_drop_orphaned_tables(): Iterate fil_system->space_list directly.

- Changed rocksdb.2pcgroup_commit.test to print information on error
- Updated myisam_views-big.result

LOCK_thd_data was used to protect both THD data and
ensure that the THD is not deleted while it was in use

This patch moves the THD delete protection to LOCK_thd_kill,
which already protects the THD for kill.

The benefits are:
- More well defined what LOCK_thd_data protects
- LOCK_thd_data usage is now much simpler and easier to verify
- Less chance of deadlocks in SHOW PROCESS LIST as there is less
  chance of interactions between mutexes
- Remove not needed LOCK_thread_count from
  thd_get_error_context_description()
- Fewer mutex taken for thd->awake()

Other things:
- Don't take mysys->var mutex in show processlist to check if thread
  is kill marked
- thd->awake() now automatically takes the LOCK_thd_kill mutex
  (Simplifies code)
- Apc uses LOCK_thd_kill instead of LOCK_thd_data

This will allow show processlist to continue, without blocking
all new connections, if some threads gets stuck while holding
LOCK_thd_data or mysys_var->mutex

Connections that has mutex 'stuck' are marked as 'Busy' in 'Command'

Todo:
Make F_BACKOFF to do 'pause' instead of just (1)

Moved InnoDB UT_RELAX_CPU() to server. Restored cross-platform LF_BACKOFF
implementation basing on UT_RELAX_CPU().

Allow DROP TABLE `#mysql50##sql-...._.` to drop tables that were
being rebuilt by ALGORITHM=INPLACE

NOTE: If the server is killed after the table-rebuilding ALGORITHM=INPLACE
commits inside InnoDB but before the .frm file has been replaced, then
the recovery will involve something else than DROP TABLE.

NOTE: If the server is killed in a true inplace ALTER TABLE commits
inside InnoDB but before the .frm file has been replaced, then we
are really out of luck. To properly handle that situation, we would
need a transactional mysql.ddl_fixup table that directs recovery to
rename or remove files.

prepare_inplace_alter_table_dict(): Use the altered_table->s->table_name
for generating the new_table_name.

table_name_t::part_suffix: The start of the partition name suffix.

table_name_t::dbend(): Return the end of the schema name.

table_name_t::dblen(): Return the length of the schema name, in bytes.

table_name_t::basename(): Return the name without the schema name.

table_name_t::part(): Return the partition name, or NULL if none.

row_drop_table_for_mysql(): Assert for #sql, not #sql-ib.

fseg_alloc_free_page_low(): Remove a bogus and redundant assertion about
fil_space_t::purpose. The debug function fsp_space_modify_check()
is asserting something similar, but more accurately.

Update the .result file. Old EXPLAIN output was incorrect due to
hitting MDEV-14563.

MDEV-14401: Stored procedure that declares a handler that catches ER_LOCK_DEADLOCK error causes thd->is_error() assertion

This was missing bug fix from MySQL wsrep i.e. Galera.
Problem was that if stored procedure declares a handler that
catches deadlock error, then the error may have been
cleared in method sp_rcontext::handle_sql_condition().
Use wsrep_conflict_state correctly to determine is the
error already sent to client.

Add test case for both this bug and MDEV-12837: WSREP: BF
lock wait long. Test requires both fixes to pass.

Problem was a merge error from MySQL wsrep i.e. Galera.

wsrep_on_check
	New check function. Galera can't be enabled
	if innodb-lock-schedule-algorithm=VATS.

innobase_kill_query
	In Galera async kill we could own lock mutex.

innobase_init
	If Variance-Aware-Transaction-Sheduling Algorithm (VATS) is
	used on Galera we fall back to First-Come-First-Served (FCFS)
	with notice to user.

Changed innodb-lock-schedule-algorithm as read-only parameter
as it was designed to be.

lock_reset_lock_and_trx_wait
	Use ib::hex() to print out transaction ID.

lock_rec_other_has_expl_req,
lock_rec_other_has_conflicting,
RecLock::add_to_waitq
lock_rec_lock_slow
lock_table_other_has_incompatible
lock_rec_insert_check_and_lock
lock_prdt_other_has_conflicting

	Change pointer to conflicting lock to normal pointer as this
	pointer contents could be changed later.

RecLock::create
	Conclicting lock pointer is moved to last parameter with
	default value NULL. This conflicting transaction could
	be selected as victim in Galera if requesting transaction
	is BF (brute force) transaction. In this case contents
	of conflicting lock pointer will be changed. Use ib::hex() to print
	transaction ids.