fts_cmp_set_sync_doc_id(), fts_load_stopword(): Start the transaction
in read-only mode if innodb_read_only is set.

fts_update_sync_doc_id(), fts_commit_table(), fts_sync(),
fts_optimize_table(): Return DB_READ_ONLY if innodb_read_only is set.

fts_doc_fetch_by_doc_id(), fts_table_fetch_doc_ids():
Remove the code to start an internal transaction or to roll back,
because this is a read-only operation.

Fixes MDEV-14761 "Assertion `!mysql_parse_status || thd->is_error() ||
thd->get_internal_handler()' failed in parse_sql"

The session object is not really needed for anything.
We can directly create and free the dummy purge_sys->query->trx.

If CREATE TABLE...FULLTEXT INDEX was initiated right before shutdown,
then the function fts_load_stopword() could commit modifications
after shutdown was initiated, causing an assertion failure in
the function trx_purge_add_update_undo_to_history().

Mark as internal all the read/write transactions that
modify fulltext indexes, so that they will be ignored by
the assertion that guards against transaction commits
after shutdown has been initiated.

fts_optimize_free(): Invoke trx_commit_for_mysql() just in case,
because in fts_optimize_create() we started the transaction as
internal, and fts_free_for_backgruond() would assert that the
flag is clear. Transaction commit would clear the flag.

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

Also, allow the MariaDB 10.2 server to link InnoDB dynamically
against ha_innodb.so (which is what mysql-test-run.pl expects
to exist, instead of the default name ha_innobase.so).

wsrep_load_data_split(): Instead of referring to innodb_hton_ptr,
check the handlerton::db_type. This was recently broken by me in
MDEV-11415.

innodb_lock_schedule_algorithm: Define as a weak global symbol,
so that WITH_WSREP will not depend on InnoDB being linked statically.
I tested this manually. Notably, running a test that only does
	SET GLOBAL wsrep_on=1;
with a static or dynamic InnoDB and
	./mtr --mysqld=--loose-innodb-lock-schedule-algorithm=fcfs
will crash with SIGSEGV at shutdown. With the default VATS
combination the wsrep_on is properly refused for both the
static and dynamic InnoDB.

ha_close_connection(): Do invoke the method also for plugins
for which UNINSTALL PLUGIN was deferred due to open connections.
Thanks to @svoj for pointing this out.

thd_to_trx(): Return a pointer, not a reference to a pointer.

check_trx_exists(): Invoke thd_set_ha_data() for assigning a transaction.

log_write_checkpoint_info(): Remove an unused DEBUG_SYNC point
that would cause an assertion failure on shutdown after deferred
UNINSTALL PLUGIN.

This was tested as follows:

cmake -DWITH_WSREP=1 -DPLUGIN_INNOBASE:STRING=DYNAMIC \
-DWITH_MARIABACKUP:BOOL=OFF ...
make
cd mysql-test
./mtr innodb.innodb_uninstall

There were two problems related to the bug report:
1. Item_datetime::get_date() was not implemented.
   So execution went through val_int() followed
   by int-to-datetime or int-to-time conversion.
   This was the reason why the optimizer did not
   work well on data with fractional seconds.
2. Item_datetime::set() did not have a TIME specific code
   to mix months and days to hours after unpack_time().
   This is why the optimizer did not work well with negative
   TIME values, as well as huge time values.

Changes:

1. Overriding Item_datetime::get_date(), to return ltime.
   This fixes the problem N1.
2. Cleanup: Moving pack_time() and unpack_time() from
   sql-common/my_time.c and include/my_time.h to
   sql/sql_time.cc and sql/sql_time.h, as they are not needed
   on the client side.
3. Adding a new "enum_mysql_timestamp_type ts_type" parameter
   to unpack_time() and moving the TIME specific code to mix
   months and days with hours inside unpack_time().
   Adding a new "ts_type" parameter to Item_datetime::set(),
   to pass it from the caller down to unpack_time().
   So now the TIME specific code is automatically called
   from Item_datetime::set(). This fixes the problem N2.
   This change also helped to get rid of duplicate TIME specific code
   from other three places, where mixing month/days to hours
   was done immediately after unpack_time().
   Moving the DATE specific code to zero hhmmssff
   from Item_func_min_max::get_date_native to inside unpack_time(),
   for symmetry.
4. Removing the virtual method in_vector::result_type(),
   adding in_vector::type_handler() instead.
   This helps to get result_type(), field_type(),
   mysql_timestamp_type() of an in_vector easier.
   Passing type_handler()->mysql_timestamp_type() as
   a new parameter to Item_datetime::set() inside
   in_temporal::value_to_item().
5. Cleaup: Removing separate implementations of in_datetime::get_value()
   and in_time::get_value(). Adding a single implementation
   in_temporal::get_value() instead.
   Passing type_handler()->field_type() to get_value_internal().

MDEV-13732 User with SELECT privilege can ALTER sequence

GAL-506 breaks galera_defaults MTR test by upping repl.proto_max again. Fix this once and for all by overwriting it with constant string since it makes little sense to check for it in this test.

lock_trx_release_locks(): Relax a debug assertion to allow
recovered TRX_STATE_COMMITTED_IN_MEMORY transactions.

trx_commit_in_memory(): Add DEBUG_SYNC instrumentation.

trx_undo_insert_cleanup(): Skip persistent changes if innodb_read_only
is set. This should only happen when a recovered committed transaction
would be cleaned up at shutdown.

The patch for MDEV-15287 made the code in Item_func_min_max::get_date_native()
dead, as the TIME data type is now handled in get_time_native().
Removing the TIME related code from get_date_native().

- Max_index_length is supported by MyISAM and Aria tables.
- Temporary is a placeholder to signal that a table is a
  temporary table. For the moment this is always "N", except
  "Y" for generated information_schema tables and NULL for
  views. Full temporary table support will be done in another task.
  (No reason to have to update a lot of result files twice in a row)

When Mariabackup gets a bad read of the first page of the system
tablespace file, it would inappropriately try to apply the doublewrite
buffer and write changes back to the data file (to the source file)!
This is very wrong and must be prevented.

The correct action would be to retry reading the system tablespace
as well as any other files whose first page was read incorrectly.
Fixing this was not attempted.

xb_load_tablespaces(): Shorten a bogus message to be more relevant.
The message can be displayed by --backup or --prepare.

xtrabackup_backup_func(), os_file_write_func(): Add a missing space
to a message.

Datafile::restore_from_doublewrite(): Do not even attempt the
operation in Mariabackup.

recv_init_crash_recovery_spaces(): Do not attempt to restore the
doublewrite buffer in Mariabackup (--prepare or --export), because
all pages should have been copied correctly in --backup already,
and because --backup should ignore the doublewrite buffer.

SysTablespace::read_lsn_and_check_flags(): Do not attempt to initialize
the doublewrite buffer in Mariabackup.

innodb_make_page_dirty(): Correct the bounds check.

Datafile::read_first_page(): Correct the name of the parameter.

When code from MySQL 5.7.9 was merged to MariaDB 10.2.2
in commit 2e814d47
an assignment validate=true was inadvertently added to the function
dict_check_sys_tables().

This causes InnoDB to open every single .ibd file on startup, even
when no crash recovery was needed.

Simply removing the assignment would make some tests fail. We do the
best to retain almost the same level of inconsistency detection.
In the test innodb.table_flags, access to one of the tables will not
be blocked despite inconsistent flags.

dict_check_sys_tables(): Remove the problematic assignment, and skip
validation in normal startup.

dict_load_table_one(): If the .ibd file cannot be opened, mark the
table as corrupted and unreadable.

fil_node_open_file(): Validate FSP_SPACE_FLAGS with the expected
flags. If reading the tablespace fails, invalidate node->handle
instead of letting it remain stale. This bug was caught by a
fil_validate() assertion failure.

fsp_flags_try_adjust(): If the tablespace file is invalid, do nothing.

        When table is renamed, the InnoDB's dictionary cache didn't
        change the ib_table->data_dir_path accordingly.
        Now it's set to NULL.

TokuDB uses USE_VALGRIND while MariaDB uses HAVE_valgrind

Fixed by defining USE_VALGRIND in TokuDB if HAVE_valgrind
is used

Fixed by adding Item::rename_fields_processor
Signed-off-by: Monty <monty@mariadb.org>