This triggered a "may be uninitialized" warning from GCC 9.2.1.
The bogus-looking condition was added in
7e916bb8

Merge branch '10.2' into 10.3

ins_node_create() does not initialize all members of que_common_t, so
zero-init them with mem_heap_zalloc().

Handle out-of-memory correctly.

Init insert_node->common.parent to fulfill the contract of thr usage.

Free insert_node subtree at row_update_vers_insert() exit.

Problem:
=======
DROP TABLE IF EXISTS was killed. The table still exists on
the master but the DDL was still logged.

Analysis:
=========
During the execution of DROP TABLE command "ha_delete_table" call is invoked
to delete the table. If the query is killed at this point, the kill command
is not handled within the code. This results in two issues.
1) The table which is not dropped also gets written into the binary log.
2) The code continues further upon receiving 'KILL QUERY'.

Fix:
===
Upon receiving the KILL command the query should stop its current execution.
Tables which were successfully dropped prior to KILL command should be
included in the binary log.

If there're multiple row versions in InnoDB, reading one row from PK
may have O(N) complexity and reading from secondary keys may have
O(N^2) complexity.

The problem occurs when there are many pending versions of the same
row, meaning that the primary key is the same, but a secondary key is
different.  The slowdown occurs when the secondary index is
traversed. This patch creates a helper class for the function
row_sel_get_clust_rec_for_mysql() which can remember and re-use
cached_clust_rec & cached_old_vers so that rec_get_offsets() does not
need to be called over and over for the clustered record.

Corrections by Kevin Lewis <kevin.lewis@oracle.com>

MDEV-20341 Unstable innodb.innodb_bug14704286

Removed test that tested the ability of interrupting long query which
is not long anymore.

Exclude SELECT and INSERT SELECT from vers_set_hist_part(). We cannot
likewise exclude REPLACE SELECT because it may REPLACE into itself
(and REPLACE generates history).

INSERT also does not generate history, but we have history
modification setting which might be interfered.

Fix error code.

Enable the rocksdb test suite. It now passes the valgrind tests.

- Include the valgrind suppressions from the FB upstream

- Use HAVE_Valgrind, not HAVE_Purify (like the rest of MariaDB code does)
  The call to DisownData() is now actually disabled under Valgrind

Starting with MDEV-12288 in MariaDB Server 10.3,
the transaction identifiers on records will be reset on purge.
Because purge might or might not run to completion before shutdown,
it could happen that the bogus transaction identifier that our
test is writing will be reset by purge after restart, and the
expected warning message on SELECT will fail to appear.

We resolve the race condition by ensuring that purge runs to
completion before the shutdown.

Use DEBUG_SYNC to hang the execution at the interesting point,
and then kill and restart the server externally. This will work
also with Valgrind. DBUG_SUICIDE() causes Valgrind to hang,
and it could also cause uninteresting reports about memory leaks.

While we are at it, let us clean up innodb.innodb_bulk_create_index_debug
so that it will actually test the desired functionality also in future
versions (with instant ADD COLUMN and DROP COLUMN) and avoid
some unnecessary restarts.

We are adding two DEBUG_SYNC points for ALTER TABLE, because there were
none that would be executed right before ha_commit_trans().

Galera threads were not registered to performance schema and
used pthread_create when mysql_thread_create should have been
used.

Added test case to verify current galera performance schema
instrumentation does work.

Test changes only.

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.

MDEV-17614 flags INSERT…ON DUPLICATE KEY UPDATE unsafe for statement-based
replication when there are multiple unique indexes. This correctly fixes
something whose attempted fix in MySQL 5.7
in mysql/mysql-server@c93b0d9a972cb6f98fd445f2b69d924350f9128a
caused lock conflicts. That change was reverted in MySQL 5.7.26
in mysql/mysql-server@066b6fdd433aa6673622341f1a2f0a3a20018043
(with a substantial amount of other changes).

In MDEV-17073 we already disabled the unfortunate MySQL change when
statement-based replication was not being used. Now, thanks to MDEV-17614,
we can actually remove the change altogether.

This reverts commit 8a346f31 (MDEV-17073)
and mysql/mysql-server@c93b0d9a972cb6f98fd445f2b69d924350f9128a while
keeping the test cases.

- mysqltest didn't free read_command_buf
- wait_for_slave_param did write different things to the log if valgrind
  was used.
- Table open cache should not write the initial variable value as it
  can depend on the configuration or if valgrind is used
- A variable in GetResult was used uninitalized

initialize_readline() is called with full pathname of executable which
sets rl_readline_name to that value.

It is expected that rl_readline_name is initialized with static name
not depending on the file name at all. Needed for setting custom
hotkeys in .inputrc

1. Fix DBUG_ASSERT(!table->pos_in_locked_tables) in tc_release_table();
2. Fix access of prematurely freed MDL_ticket: don't close ticket if table was not closed;
3. Fix deadlock after erroneous ALTER.

mysql_alter_table() leaves dirty table->m_needs_reopen in case of
error exit which then incorrectly treated by mysql_lock_tables().

Prevent conflicting clauses at parser level.

Clear HA_VERSIONED_TABLE flag for DROP SYSTEM VERSIONING (for the sake
of strictness).

Special case for DROP PERIOD when system fields are implicit.

For MODE_SIMULTANEOUS_ASSIGNMENT it is required to return back field
offsets from record[1] to record[0]. 'continue' in warning branch did
skip of rfield->move_field_offset() call.

Wrong value F_WRLCK for thr_lock_type.

Prune to now-partition when there is no FOR SYSTEM_TIME clause.