As btrfs showed, a partial read of data in AIO /O_DIRECT circumstances can
really confuse MariaDB.

Filipe Manana (SuSE)[1] showed how database programmers can assume
O_DIRECT is all or nothing.

While a fix was done in the kernel side, we can do better in our code by
requesting that the rest of the block be read/written synchronously if
we do only get a partial read/write.

Per the APIs, a partial read/write can occur before an error, so
reattempting the request will leave the caller with a concrete error to
handle.

[1] https://lore.kernel.org/linux-btrfs/CABVffENfbsC6HjGbskRZGR2NvxbnQi17gAuW65eOM+QRzsr8Bg@mail.gmail.com/T/#mb2738e675e48e0e0778a2e8d1537dec5ec0d3d3a

Also spell synchronously correctly in other files.

This fixes commit 77c184df.

The virtual member function that was added in
commit 1766a18e
needs to be declared "override".

MDEV-28030 row_discard_tablespace_for_mysql() can unlock data dictionary without locking data dictionary

- row_discard_tablespace_for_mysql() could unlock the data dictionary lock without locking it in the first place.

- During rollback of InnoDB DDL, it un-necessary removes the table
from fts_optimize_wq. Removal of fts table from fts_optimize_wq when
it has only one fulltext and it is being rollbacked.

Ever since commit 9608773f
we no longer disable innodb_stats_persistent.
Ever since commit 45a05fda
updates of the InnoDB persistent statistics are covered by MDL.

Externally kill and restart the server, and remove the
unreliable crash_after_checkpoint.

Per https://gcc.gnu.org/onlinedocs/gcc/PowerPC-Hardware-Transactional-Memory-Built-in-Functions.html

The .. high level HTM interface .. is common between PowerPC and S/390

Reimplemented the transactional_lock_enabled() detection mechanism for
s390x and POWER based on SIGILL. This also gives non-Linux based unixes
the ability to use HTM. The implementation is based off openssl.
(ref:
https://github.com/openssl/openssl/blob/1c0eede9827b0962f1d752fa4ab5d436fa039da4/crypto/s390xcap.c#L104)

The other ppc64{,le} problems with getauxvec based detection:
* Checking PPC_FEATURE2_HTM_NOSC not needed as we do not do syscalls while
  in a transactional state.
* As we don't use, and never should use PPC_FEATURE2_HTM_NO_SUSPEND,
  or do syscalls while in transactional state, don't test it.
From: https://www.kernel.org/doc/html/v5.4/powerpc/syscall64-abi.html#transactional-memory

S390x high level __builtin_tbegin functions in the htmxlintrin.h are not
inline. This header file can be included once in the entire set of sources for
a linked target, otherwise duplicate symbols occur. While we could use inline
xabort/xend functions using the low level interface, we keep this the same as
ppc64 for simplicity.

SLES-15, gcc-7, appeared to want everything that included the htmlxlintrin to
be compiled with -mhtm otherwise the __builtin_t{func} where not defined
(in addition to a #ifdef __HTM__ #error). Debian sid gcc-11.2 wanted the same
on ppc64le/ppc64. In general we want to avoid a wide spread use of architecture
cflags as it makes justifications for selective optimizations easier.
(ref: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1006702)

buf_page_get_low(): Assert that the block not be read-fixed.
It may be write-fixed while we only hold a shared latch on the page.
Page writes are protected by U latches, which are compatible with S.
In all other places where we assert that the block not be IO-fixed,
we are holding U or X latch, which does prevent concurrent file I/O.

The first step for deprecating innodb_autoinc_lock_mode(see MDEV-27844) is:
- to switch statement binlog format to ROW if binlog format is MIXED and
the statement changes autoincremented fields
- issue warnings if innodb_autoinc_lock_mode == 2 and binlog format is
STATEMENT

The warning out of OPTIMIZE
  Statement is unsafe because it uses a system function
was indeed counterfactual and was resulted by checking an
insufficiently strict property of lex' sql_command_flags.

Fixed with deploying an additional checking of weather
the current sql command that modifes a share->non_determinstic_insert
table is capable of generating ROW format events.
The extra check rules out the unsafety to OPTIMIZE et al, while the
existing check continues to do so to CREATE TABLE (which is
perculiarly tagged as ROW-event generative sql command).

As a side effect sql_sequence.binlog test gets corrected and
binlog_stm_unsafe_warning.test is reinforced to add up
an unsafe CREATE..SELECT test.

Cannot have a function trx_has_lock_x hot and cold.

zstd-1.1.3 is needed however stretch has only 1.1.2.

Move to distro version based checks as checks against the
apt-cache are unreliable if there is no cache.

There is only a very small range of gcc compiler versions
that allow the built_{htm} functions to be defined without -mhtm
being specified as a global C{,XX}FLAGS.

Because the design is centered around enable HTM only in the
functional blocks that use it, this breaks on the inclusion
of the htmxlintrin.h header that includes this.

As a partial mitigation, extented to GNU/clang compilers,
transaction functions gain the attribute "hot".

In general the use of htm is around the optimistic
transaction ability of the function. The key part of using the
hot attribute is to place these functions together so that
a maximization of icache, tlb and OS paging can ensure that
these can be ready to execute by any thread/cpu with the
minimum amount of overhead.

POWER is particularly affected here because the xbegin/xend
functions are not inline.

srw_lock.cc requires the -mhtm cflag, both in the storage
engine and the unit tests.

The commits a73acf6c and
4d74bac8 updated the PCRE library to a new
version, which in turn requires CMake 3.0. That does not exist in CentOS 7
nor 8, so builds started failing.

Actually the build should not be downloading anything at all. The root
cause was that pcre2-devel was missing from the dependencies. This was
originally not detected, as the download fallback had masked the issue.

MDEV-27025 allows to insert records before the record on which DELETE is
locked, as a result the DELETE misses those records, what causes serious ACID
violation.

Revert MDEV-27025, MDEV-27550. The test which shows the scenario of ACID
violation is added.

During an increase in resize, the new curr_size got a value
less than old_size.

As n_chunks_new and n_chunks have a strong correlation to the
resizing operation in progress, we can use them and remove the
need for old_size.

For convienece the n_chunks_new < n_chunks is now the is_shrinking
function.

The volatile compiler optimization on n_chunks{,_new} is removed
as real mutex uses are needed.

Other n_chunks_new/n_chunks methods:

n_chunks_new and n_chunks almost always read and altered under
the pool mutex.

Exceptions are:
* i_s_innodb_buffer_page_fill,
* buf_pool_t::is_uncompressed (via is_blocked_field)
These need reexamining for the need of a mutex, however comments
indicates this already.

get_n_pages has uses in buffer pool load, recover log memory
exhaustion estimates and innodb status so take the minimum number
of chunks for safety.

The buf_pool_t::running_out function also uses curr_size/old_size.
We replace this hot function calculation with just n_chunks_new.
This is the new size of the chunks before the resizing occurs.

If we are resizing down, we've already got the case we had previously
(as the minimum). If we are resizing upwards, we are taking an
optimistic view that there will be buffer chunks available for locks.
As this memory allocation is occurring immediately next the resizing
function it seems likely.

Compiler hint UNIV_UNLIKELY removed to leave it to the branch
predictor to make an informed decision.

Added test case of a smaller size than the Marko/Roel original
in JIRA reducing the size to 256M. SEGV hits roughly 1/10 times
but its better than a 21G memory size.

Reviewer: Marko

The virtual member function handler::reset_auto_increment(ulonglong)
is only ever invoked by the default implementation of the virtual
member function handler::truncate().

Because ha_innobase::truncate() overrides handler::truncate() without
ever invoking handler::truncate(), some InnoDB member functions are
never called.

ha_innobase::innobase_reset_autoinc(), ha_innobase::reset_auto_increment():
Removed (unreachable code).

ha_innobase::delete_all_rows(): Removed. The default implementation
handler::delete_all_rows() works just as fine.

- InnoDB FTS DDL decrements the FTS_DOC_ID when there is a
deleted marked record involved. FTS_DOC_ID must never be
reused. The purpose of FTS_DOC_ID is to be a unique row
identifier that will be changed whenever a fulltext indexed
column is updated.