* TIMESTAMP precedence fixed.

Unit-based history point (vers_history_point_t; Vers_history_point).

Update partition stats on ha_partition::write_row()

SQL: DROP PERIOD FOR SYSTEM_TIME syntax

and remove ER_VERS_SYS_FIELD_EXISTS

originally by: Eugene Kosov

also, don't rotate versioning partitions for DELETE HISTORY

originally by: Aleksey Midenkov

implement log-term TODO item, convert redundant if()-s into asserts.

don't allow to discover WITH SYSTEM VERSIONING clause

originally by: Aleksey Midenkov

table might be NULL in ha_partition::engine_name()
(test case pushed into 5.5)

There is only one lock_sys. Allocate it statically in order to avoid
dereferencing a pointer whenever accessing it. Also, align some
members to their own cache line in order to avoid false sharing.

lock_sys_t::create(): The deferred constructor.

lock_sys_t::close(): The early destructor.

Merge pull request #622

is not supported

Allowed to use recursive references in derived tables.
As a result usage of recursive references in operands of
INTERSECT / EXCEPT is now supported.

fix the compilation error.
no support for plugins yet.

ReadView::is_open() was supposed to be called by view owner thread
exclusively. Use ReadView::get_state() instead.

At innodb_force_recovery=5 or bigger, trx_lists_init_at_db_start()
no longer initialises the purge_sys. Adjust an assertion accordingly.

rocksdb and spider

There is only one purge_sys. Allocate it statically in order to avoid
dereferencing a pointer whenever accessing it. Also, align some
members to their own cache line in order to avoid false sharing.

purge_sys_t::create(): The deferred constructor.

purge_sys_t::close(): The early destructor.

undo::Truncate::create(): The deferred constructor.
Because purge_sys.undo_trunc is constructed before the start-up
parameters are parsed, the normal constructor would copy a
wrong value of srv_purge_rseg_truncate_frequency.

TrxUndoRsegsIterator: Do not forward-declare an inline constructor,
because the static construction of purge_sys.rseg_iter would not have
access to it.

trx_purge(): Remove the parameter limit or batch_size, which is
always passed as srv_purge_batch_size.

trx_purge_attach_undo_recs(): Remove the parameters purge_sys, batch_size.
Refer to srv_purge_batch_size.

trx_purge_wait_for_workers_to_complete(): Remove the parameter purge_sys.

Add innodb debug system variable, innodb_buffer_pool_load_pages_abort, to test
the behaviour of innodb_buffer_pool_load_incomplete.
(innodb_buufer_pool_dump_abort_loads.test)

This status variable indicates that an innodb buffer pool load never
completed and dumping at shutdown would result in an incomplete dump file.

This status variable is set to 1 once a buffer pool loads. Upon a successful
load this status variable returns to 0.

With this status variable set, the system variable
innodb_buffer_pool_dump_at_shutdown==1 will have no effect as dumping after
an incomplete load will generate a less complete dump file than the current
one.

If a user aborts a buffer pool load by changing the system variable
innodb_buffer_pool_load_abort=1 will cause the the status variable
innodb_buffer_pool_load_incomplete to remain set to 1.

A shutdown that occurs while innodb is loading the buffer pool will
not save the buffer pool on shutdown.

A user may indirectly set innodb_buffer_pool_load_incomplete
to 0 by:
* Forcing a load, by setting innodb_buffer_pool_load_now=ON, or
* Forcing a dump, by setting innodb_buffer_pool_dump_now=ON

This will enable the next dump on shutdown to complete.
Signed-off-by: Daniel Black <daniel.black@au.ibm.com>

Before MDEV-12288 in MariaDB 10.3.1, InnoDB used to partition
the persistent transaction undo log into insert_undo and update_undo.

MDEV-12288 repurposes the update_undo as the single undo log.
In order to support an upgrade from earlier MariaDB versions,
the insert_undo is recovered in data structures, called old_insert.

An assertion failure occurred in TrxUndoRsegsIterator::set_next()
when an incomplete transaction was recovered with both insert_undo
and update_undo log. This could be easily demonstrated by starting
./mysql-test-run --manual-gdb innodb.read_only_recovery
in MariaDB 10.2, and after the first kill, start up the MariaDB 10.3
server with the same parameters.

The problem is that MariaDB 10.3 would roll back the recovered
transaction, and finally "commit" it twice (with all changes to
data rolled back), both insert_undo and update_undo with the same
commit end identifier (trx->no).

Our fix is to introduce a "commit number" that comprises two components:
(trx->no << 1 | !old_insert). In this way, the assertion in the purge
subsystem can be relaxed so that only the trx->no component must match.

Regression introducted in c2118a08 where LOCK_thd_data was moveed
to LOCK_thd_kill

TrxUndoRsegs::append(): Remove.

TrxUndoRsegsIterator::set_next(): Add a debug assertion that
demonstrates that the merging of rollback segments never occurs.
Since MDEV-12289 or earlier, MariaDB 10.2 will not make any
temporary undo log accessible to the purge subsystem.
(Also MySQL 5.7 would skip the purge of any undo log for
temporary tables, but not before parsing and buffering those
temporary undo log records.)

Construct directly from trx_rseg_t&.
push_back(), size(): Remove.

Also, remove the field undo_rseg_space.
Apparently its purpose was to avoid problems with
temporary undo logs, which MySQL 5.7 unnecessarily adds to
the purge system. (Temporary undo log records are not purged.)
MariaDB 10.2 fixed this in MDEV-12289 or earlier.

purge_iter_t::operator<=(): Ordering comparison.
This replaces trx_purge_check_limit() with the difference that
we are not comparing undo_rseg_space. (In MariaDB, temporary
undo logs do not enter the purge subsystem at all.)

purge_sys_t::done: Remove. This was not used for anything.

purge_sys_t::tail: Renamed from purge_sys_t::iter.

purge_sys_t::head: Renamed from purge_sys_t::limit.

Merge pull request #364

Regression introducted in c2118a08 where LOCK_thd_data was moveed
to LOCK_thd_kill

despite the name, it logs both stdout and stderr

tokudb apparently requires perfschema now