don't expand AS OF in views, and, in particular, don't auto-add
AS OF NOW().

Hide INVISIBLE_SYSTEM columns from writes and from fix_vcol_expr().

enum_mark_columns -> enum_column_usage
mark_used_columns -> column_usage

further commits will replace MARK_COLUMN_NONE with
COLUMN_READ and COLUMN_WRITE that convey the intention
without causing columns to be marked

update all unique keys, not just PK

don't add columns to the drop list, INVISIBLE_SYSTEM columns
cannot be recognized as specified by the user

* don't disclose INVISIBLE_FULL columns in USING and NATURAL JOIN
* other INVISIBLE columns must me mentioned by name in USING,
  they are hidden from NATURAL JOIN

don't duplicate functionality, use TABLE::find_field_by_name()

also, set cached_field_index_ptr for _rowid field

use name hash, just like find_field_in_table() does

replication tests

Standard compatible behavior for UPDATE: all assignments in SET
are executed "simultaneously", not left-to-right. And `SET a=b,b=a`
will swap the values.

cleanup. use "command -v" instead of "which"
simplify some checks.

For placement new, throw() exception specification was removed by
accident in 8fe04a3d , making  debug
tests, that simulate out-of-memory situations, fail (e.g filesort_debug)

Correctly initialize fake IPs.

innobase_add_instant_try(): If the leftmost leaf page does not contain
other records than the 'default row', only empty the table if there
are no successor pages.

When a table or partition which was not empty during a previous
instant ADD COLUMN became empty later, and now with this subsequent
instant ADD COLUMN we have the opportunity to convert the empty table
or partition to 'non-instant' format.

Similarly, if the table or partition is empty to begin with, that is,
it does not even contain a 'default row' record, we can use the
'non-instant' format.

Until now, InnoDB inefficiently compared the aligned fields
FIL_PAGE_PREV, FIL_PAGE_NEXT to the byte-order-agnostic value FIL_NULL.

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

Compiler optimizations were switched off due to
MySQL Bug #19424, #36366, #34297, due to an alleged compiler bug.
No  proper analysis of code generation was done back then, thus proof of
a compiler bug is missing.

Even if there was a compiler bug 13 years ago, it could have been fixed.
Will wait and see if there are any complains or crashes

trx_undo_rec_copy(): Use a debug assertion. In a non-debug build,
with len<0 (which this assertion is really testing for)
we should still typically crash due to running out of memory.

Replace all occurrences of the is_clust() method with is_primary(),
because that is what is actually meant. (Also the change buffer
tree would count as a clustered index.)

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

No deterministic test case for the bug was found. The simplest test
cases may be related to MDEV-11415, which suppresses undo logging for
ALGORITHM=COPY operations. In those operations, in the spirit of
MDEV-12288, we should actually have written reset_trx_id instead of
using the transaction identifier of the current transaction
(and a bogus value of DB_ROLL_PTR=0). However, thanks to MySQL Bug#28432
which I had fixed in MySQL 5.6.8 as part of WL#6255, access to the
rebuilt table by earlier-started transactions should actually have been
refused with ER_TABLE_DEF_CHANGED.

reset_trx_id: Move the definition to data0type.cc and the declaration
to data0type.h.

btr_cur_ins_lock_and_undo(): When undo logging is disabled, use the
safe value that corresponds to reset_trx_id.

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(): Init ins_node_t::sys_buf[] to reset_trx_id.

row_ins_buf(): Only if undo logging is enabled, copy trx->id
to node->sys_buf. Otherwise, rely on the initialization in
row_ins_alloc_sys_fields().

row_purge_reset_trx_id(): Invoke mlog_write_string() with reset_trx_id
directly. (No functional change.)

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.

PageConverter::adjust_cluster_record(): Fix
MDEV-15249 Crash in MVCC read after IMPORT TABLESPACE
by resetting the system fields to reset_trx_id instead of writing
the current transaction ID (which will be committed at the
end of the IMPORT TABLESPACE) and DB_ROLL_PTR=0.
This can partially be viewed as a follow-up fix of MDEV-12288,
because IMPORT should already then have written
DB_TRX_ID=0 and DB_ROLL_PTR=1<<55 to prevent unnecessary
DB_TRX_ID lookups in subsequent accesses to the table.

fix a couple "initialization skipped by goto" and other new errors.

no matching operator delete found; memory will not be freed if initialization throws an exception

Added a no-op delete() for MEM_ROOT based placement-new()

But set _CRT_NONSTDC_NO_WARNINGS to silence silly warnings about
ANSI C function being non-standard

Remove now deprecated GetVersion()/GetVersionEx(),except single case
where where it is really needed, in feedback plugin. Remove checks for
Windows NT.

Avoid old IPv4-only inet_aton, which generated the warning.

The test was used to result in mismatch due to unaccounted specifics
of the master-slave handshake protocol that sets the Slave_IO_Running
status to true while the semisync master status is set to active a bit later.

The test is refined to expect that.

Fixed that Truncate_versioning_privilege works as any other privilege
during upgrade:

- If the privilege field does not exists, add it to the user and db tables.
  If the user had super_privilege then the user will also get the new
  Truncate_versioning_privilege.

This is done to ensure that if one has GRANT ALL PRIVILEGE before, one
will continue to have it after running mysql_upgrade.

This also fixes a bug where the Truncate_versioning_privilege