also add const to methods in List<> and Hash_set<>
while we're at it

MDEV-33407 Parser support for vector indexes

The syntax is

  create table t1 (... vector index (v) ...);

limitation:
* v is a binary string and NOT NULL
* only one vector index per table
* temporary tables are not supported

MDEV-33404 Engine-independent indexes: subtable method

added support for so-called "high level indexes", they are not visible
to the storage engine, implemented on the sql level. For every such
an index in a table, say, t1, the server implicitly creates a second
table named, like, t1#i#05 (where "05" is the index number in t1).
This table has a fixed structure, no frm, not accessible directly,
doesn't go into the table cache, needs no MDLs.

MDEV-33406 basic optimizer support for k-NN searches

for a query like SELECT ... ORDER BY func() optimizer will use
item_func->part_of_sortkey() to decide what keys can be used
to resolve ORDER BY.

let the caller tell init_tmp_table_share() whether the table
should be thread_specific or not.

In particular, internal tmp tables created in the slave thread
are perfectly thread specific

create templates

  thd->alloc<X>(n) to use instead of (X*)thd->alloc(sizeof(X)*n)

and the same for thd->calloc(). By the default the type is char,
so old usage of thd->alloc(size) works too.

This partially reverts 43623f04

Engines have to set ::position() after ::write_row(), otherwise
the server won't be able to refer to the row just inserted.
This is important for high-level indexes.

heap part isn't reverted, so heap doesn't support high-level indexes.
to fix this, it'll need info->lastpos in addition to info->current_ptr

needed to get partitioning and information about
secondary objects

the information about index algorithm was stored in two
places inconsistently split between both.

BTREE index could have key->algorithm == HA_KEY_ALG_BTREE, if the user
explicitly specified USING BTREE or HA_KEY_ALG_UNDEF, if not.

RTREE index had key->algorithm == HA_KEY_ALG_RTREE
and always had key->flags & HA_SPATIAL

FULLTEXT index had  key->algorithm == HA_KEY_ALG_FULLTEXT
and always had key->flags & HA_FULLTEXT

HASH index had key->algorithm == HA_KEY_ALG_HASH or HA_KEY_ALG_UNDEF

long unique index always had key->algorithm == HA_KEY_ALG_LONG_HASH

In this commit:

All indexes except BTREE and HASH always have key->algorithm
set, HA_SPATIAL and HA_FULLTEXT flags are not used anymore (except
for storage to keep frms backward compatible).

As a side effect ALTER TABLE now detects FULLTEXT index renames correctly

Bounded_queue<> pretended to be a typesafe C++ wrapper
on top of pure C queues.h.

But it wasn't, it was tightly bounded to filesort and only useful there.

* implement Queue<> - a typesafe C++ wrapper on top of QUEUE
* move Bounded_queue to filesort.cc, remove pointless "generalizations"
  change it to use Queue.
* remove bounded_queue.h
* change subselect_rowid_merge_engine to use Queue, not QUEUE

as it can never be null (only "" or "disabled")

Cleanup unnecessary whitespace at the end of lines and end of files
in the unittest/ directory. Note that all code changes are
non-functional.

All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.

As this is MariaDB then also variable names in
mariadb-server.*inst should correlate when possible
this change variable and directory names

Gain MySQL compatibility by allowing table aliases in a single
table statement.

This now supports the syntax of:

DELETE [delete_opts] FROM tbl_name [[AS] tbl_alias] [PARTITION (partition_name [, partition_name] ...)] ....

The delete.test is from MySQL commit 1a72b69778a9791be44525501960b08856833b8d
/ Change-Id: Iac3a2b5ed993f65b7f91acdfd60013c2344db5c0.

Co-Author: Gleb Shchepa <gleb.shchepa@oracle.com> (for delete.test)

Reviewed by Igor Babaev (igor@mariadb.com)

Result file needed re-recording to account for the
new information_schema columns

With that, it is possible to restore the full "instance" from a backup
made with mariadb-dump --dir

The patch implements executing DDL (tables, views, triggers) using
statements that are stored in .sql file, created by mariadb-dump
--dir .

Care is taken of creating triggers correctly after the data is loaded,
disabling foreign keys and unique key checks etc.

The files are loaded in descending order by datafile size -
to ensure better work distribution when running with --parallel option.

In addition to --dir option, following options are implemented for
partial restore

include-only options:
--database             -  import one or several databases
--table                -  import one or several tables

exclude options:
--ignore-database      -. ignore one or several databases when importing
--ignore-table         -  to ignore one or several tables when importing

All options above are only valid together with --dir option,
and can be specified multiple times.

Use threadpool, instead of one-thread-and-connection-per-table

Fix tpool to not use maintenance timer for fixed pool size.

Trivial batch, using the handler statistics already collected for
the slow query log.

The reason for the changes in test cases was mainly to change to use
select TABLE_SCHEMA ... from information_schema.table_statistics instead
of 'show table_statistics' to avoid future changes to test results
if we add more columns to table_statistics.

There is no need for a character-set-server configuration when utf8mb4
is now the server default.

Also remove the character-set-collations as its no longer required and
the uca1400_ai_ci is now the default for all character sets that support
it. ref: MDEV-25829 / MDEV-34430.

Changing the default server character set from latin1 to utf8mb4.

Rename some threads to workaround this restrictions,
e.g "rpl_parallel_thread"->"rpl_parallel",
"slave_background" -> "slave_bg" etc.

Use SetThreadDescription/pthread_setname_np to give threads a name.

Use SetThreadDescription/pthread_setname_np to give threads a name.