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

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.

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>

Before that line there is call to buf_page_get_gen that could
return block = NULL when decrypting a page fails. However,
we should set error to be != DB_SUCCESS also. In error log
there was error about decompression but in that code there
is one case where error is not set correctly.

This MySQL 5.5 test innodb_zip.innodb_prefix_index_lifted
was renamed in MySQL 5.7. In
commit 2e814d47
the test was inadvertently removed, instead of being renamed.

The absence of this test caused a regression in MariaDB 10.2:
MDEV-15257 Invalid CREATE INDEX fails to report error correctly

page_zip_write_rec(): Do not attempt to access a non-existing
DB_TRX_ID column when writing a record to a non-leaf page.

add a test that restores the data from a binlog

Fix reinit_io_cache(WRITE_CACHE) with non-zero seek_offset.
Run encryption.tempfiles with and without binlog checksums.

The update was lost during merge.

cte_nonrecursive.test with --embedded.

This also fixed some problems for embedded CTEs.
Adjusted test results accordingly.

Timing problem as sometimes table is marked as encrypted but
sometimes we are not sure and table is just marked missing.

Add myrocks hotbackup

Rollback attempted to dereference DB_ROLL_PTR=0, which cannot possibly
be a valid undo log pointer. A safe canonical value would be
roll_ptr_t(1) << ROLL_PTR_INSERT_FLAG_POS
which is what was chosen in MDEV-12288.

This bug was reproduced in 10.3 only. Potentially, the problem could
have been introduced by MDEV-11415, which suppresses undo logging for
ALGORITHM=COPY operations. In those operations, we should actually
have written the safe value of DB_ROLL_PTR instead of writing 0.
However, the test in commit 5421e3ae
demonstrates that access to the rebuilt table by earlier-started
transactions should actually have been refused with ER_TABLE_DEF_CHANGED.

btr_cur_ins_lock_and_undo(): When undo logging is disabled, use the
safe value of DB_ROLL_PTR.

btr_cur_optimistic_insert(): Validate the DB_TRX_ID,DB_ROLL_PTR before
inserting into a clustered index leaf page.

ins_node_t::sys_buf[]: Replaces row_id_buf and trx_id_buf and some
heap usage.

row_ins_alloc_sys_fields(): Initialize ins_node_t::sys_buf[].

trx_undo_page_report_modify(): Assert that the DB_ROLL_PTR is not 0.

trx_undo_get_undo_rec_low(): Assert that the roll_ptr is valid before
trying to dereference it.

dict_index_t::is_primary(): Check if the index is the primary key.

Before killing the server, we have to FLUSH TABLES in order to
prevent the corruption of any MyISAM system tables.

PageConverter::adjust_cluster_record(): Instead of writing
the invalid value DB_ROLL_PTR=0, write a value that indicates
a fresh insert, that is, prevents the DB_ROLL_PTR from being
dereferenced in any circumstances.

It can be argued that IMPORT TABLESPACE should actually
update the dict_index_t::trx_id to prevent older transactions
from accessing the table, similar to what I did on table
rebuild in MySQL 5.6.6 in
https://github.com/mysql/mysql-server/commit/03f81a55f221095d397c375afe8a10c8038da339

Use unsigned comparison.