MEM_HEAP_BTR_SEARCH: Remove. Let us handle this special type of
mem_heap_t allocations in the only compilation unit, btr0sea.cc.

mem_block_info_t::ahi_block: Replaces free_block. This caches one
buffer page for use in adaptive hash index allocations. This is
protected by btr_search_sys_t::partition::latch. It only is
Atomic_relaxed because btr_search_free_space() is following a
pattern of test, lock, and test.

btr_search_check_free_space(): Protect the ahi_block with a
shared AHI partition latch. We must recheck btr_search_enabled after
acquiring the latch in order to avoid a race condition with
btr_search_disable(). Using a shared latch instead of an exclusive one
should reduce contention with btr_search_guess_on_hash() and other
operations when running with innodb_adaptive_hash_index=ON.

This has been tested by running the regression test suite
with the adaptive hash index enabled:
./mtr --mysqld=--loose-innodb-adaptive-hash-index=ON

build_fts_hidden_table(): Correct a mistake that had been made in
commit 903ae300 (MDEV-30655).

purge_sys_t::get_page(): Avoid accessing a freed reference to pages[id]
after pages.erase(id).  This heap-use-after-free would sometimes be
caught by AddressSanitizer.

purge_sys_t::iterator::free_history_rseg(): Do not crash if undo=nullptr
(the database is corrupted).

Reviewed by: Debarun Banerjee

xtest(): Correct the declaration.

Analysis:
The value gets appended as string instead of unescaped json value

Fix:
Append the value of json in a temporary string and then store it in the
field instead of directly storing as string.

Another chance for cutting back overhead due to C++ exceptions being
enabled; the `dict_sys_t` class is a good candidate because its
locking methods are called frequently.

Binary size reduction this time:

    text	  data	   bss	   dec	   hex	filename
 24448622	2436488	9473537	36358647	22ac9f7	build/release/sql/mariadbd
 24448474	2436488	9473601	36358563	22ac9a3	build/release/sql/mariadbd

MariaDB is compiled with C++ exceptions enabled, and that disallows
some optimizations (e.g. the stack must always be unwinding-safe).  By
adding `noexcept` to functions that are guaranteed to never throw,
some of these optimizations can be regained.  Low-level locking
functions that are called often are a good candidate for this.

This shrinks the executable a bit (tested with GCC 14 on aarch64):

    text	  data	   bss	   dec	   hex	filename
 24448910	2436488	9473185	36358583	22ac9b7	build/release/sql/mariadbd
 24448622	2436488	9473537	36358647	22ac9f7	build/release/sql/mariadbd

commit_try_norebuild(): If the STATS_PERSISTENT attribute of the table
is being changed to disabled, drop the persistent statistics of the table.

Last commit on libmarias3 broke non-gcc builds by excluding
the most important aspect, the snprintf being executed.

Reviewer: Andrew Hutchings <andrew@mariadb.org>
Ref: https://github.com/mariadb-corporation/libmarias3/pull/130

(Polished initial patch by Alexey Botchkov)
Make the code handle DEFAULT values of any datatype

- Make Json_table_column::On_response::m_default be Item*, not LEX_STRING.
- Change the parser to use string literal non-terminals for producing
  the DEFAULT value
-- Also, stop updating json_table->m_text_literal_cs for the DEFAULT
   value literals as it is not used.

Applied SR transaction on the child table was not BF aborted by TOI running
on the parent table for several reasons:

Although SR correctly collected FK-referenced keys to parent, TOI in Galera
disregards common certification index and simply sets itself to depend on
the latest certified write set seqno.

Since this write set was the fragment of SR transaction, TOI was allowed to
run in parallel with SR presuming it would BF abort the latter.

At the same time, DML transactions in the server don't grab MDL locks on
FK-referenced tables, thus parent table wasn't protected by an MDL lock from
SR and it couldn't provoke MDL lock conflict for TOI to BF abort SR transaction.

In InnoDB, DDL transactions grab shared MDL locks on child tables, which is not
enough to trigger MDL conflict in Galera.

InnoDB-level Wsrep patch didn't contain correct conflict resolution logic due to
the fact that it was believed MDL locking should always produce conflicts correctly.

The fix brings conflict resolution rules similar to MDL-level checks to InnoDB,
thus accounting for the problematic case.

Apart from that, wsrep_thd_is_SR() is patched to return true only for executing
SR transactions. It should be safe as any other SR state is either the same as
for any single write set (thus making the two logically equivalent), or it reflects
an SR transaction as being aborting or prepared, which is handled separately in
BF-aborting logic, and for regular execution path it should not matter at all.
Signed-off-by: Julius Goryavsky <julius.goryavsky@mariadb.com>

Starting with GCC 7 and clang 15, single-bit operations such as
fetch_or(1) & 1 are translated into 80386 instructions such as
LOCK BTS, instead of using the generic translation pattern
of emitting a loop around LOCK CMPXCHG.

Given that the oldest currently supported GNU/Linux distributions
ship GCC 7, and that older versions of GCC are out of support,
let us remove some work-arounds that are not strictly necessary.
If someone compiles the code using an older compiler, it will work
but possibly less efficiently.

srw_mutex_impl::HOLDER: Changed from 1U<<31 to 1 in order to
work around https://github.com/llvm/llvm-project/issues/37322
which is specific to setting the most significant bit.

srw_mutex_impl::WAITER: A multiplier of waiting requests.
This used to be 1, which would now collide with HOLDER.

fil_space_t::set_stopping(): Remove this unused function.

In MSVC we need _interlockedbittestandset() for LOCK BTS.

Fix for v. 10.6

Aria transaction ids are uint16 rather than uint.

Change the type to be more accurate.

The issue is caused by a race between buf_page_create_low getting the
page from buffer pool hash and buf_LRU_free_page evicting it from LRU.

The issue is introduced in 10.6 by MDEV-27058
commit aaef2e1d
MDEV-27058: Reduce the size of buf_block_t and buf_page_t

The solution is buffer fix the page before releasing buffer pool mutex
in buf_page_create_low when x_lock_try fails to acquire the page latch.

The lsof utility is prone to blocking on system calls that
it uses to obtain information about sockets (or files, devices,
etc.). This behavior is described in its own documentation.
It has a '-b' option (in combination with warnings suppression
via '-w') that reduces the probability of blocking, introducing
new problems (luckily probably not relevant for our use case).
However, there is no guarantee that it will not hang on some
distributions, with some TCP/IP stack implementations, or with
some filesystems, etc. Also, of the three utilities that are
suitable for our purposes, lsof is the slowest. So if there
are other utilities that we use during SST, such as 'ss' or
'sockstat', it is reasonable to use them instead of lsof.
This commit changes the prioritization of utilities, it does
not need additional tests (besides the numerous SST tests
already available in the galera suites). If the system still
need to use lsof, this commit adds the '-b' and '-w' options
to it command line - to reduce the likelihood of blocking.

Removed handling of the long-unsupported xtrabackup_pid file,
as it is not even created by modern versions of mariabackup.
Instead, added stopping of the asynchronous process that
mariabackup runs (if it is still active) to the exception
handler.

This commit makes the SST script for mariabackup more
resilient to unexpected terminations or hangs while
mariabackup or when SST scripts in a previous session
are still running (in reality they were hung while
waiting for something).

GCC 12.2.0 could issue -Wnonnull for an unreachable call to
strlen(new_path).  Let us prevent that by replacing the condition
(type == FILE_RENAME) with the equivalent (new_path).
This should also optimize the generated code, because the life time
of the parameter "type" will be reduced.

my_b_encr_write(): Initialize also block_length, and at the same time
last_block_length, so that all 128 bits can be initialized with fewer
writes. This fixes an error that was caught in the test
encryption.tempfiles_encrypted.

test_my_safe_print_str(): Skip a test that would attempt to
display uninitialized data in the test unit.stacktrace.
Previously, our CI did not build unit tests with MemorySanitizer.

handle_delayed_insert(): Remove a redundant call to pthread_exit(0),
which would for some reason cause MemorySanitizer in clang-19 to
report a stack overflow in a RelWithDebInfo build. This fixes a
failure of several tests.

Reviewed by: Vladislav Vaintroub

Emit a warning in the event that we finished processing input files
before reaching the boundary indicated by --stop-datetime.

Emit a warning in the event that we finished processing input files
before reaching the boundary indicated by --stop-position.

buf_page_t::read_complete(): Fix an incorrect condition that had been
added in commit aaef2e1d (MDEV-27058).
Also for compressed-only pages we must remember that buffered changes
may exist.

buf_read_page(): Correct the function comment; this is for a synchronous
and not asynchronous read. Pass the parameter unzip=true to
buf_read_page_low(), because each of our callers will be interested in
the uncompressed page frame. This will cause the test
encryption.innodb-compressed-blob to emit more errors when the
correct keys for decrypting the clustered index root page are unavailable.

Reviewed by: Debarun Banerjee

buf_pool_t::page_fix(): If a change buffer merge may be needed on a
ROW_FORMAT=COMPRESSED page that exists in compressed-only format in
the buffer pool, go ahead to decompress the block. This fixes an
infinite loop.

Reviewed by: Debarun Banerjee

Add support for removing the Content-Type header to the S3 engine. This
is required for compatibility with some S3 providers.

This also adds a provider option to the S3 engine which will turn on
relevant compatibility options for specific providers.

This was required for getting MariaDB S3 engine to work with "Huawei
Cloud S3".
To get Huawei S3 storage to work on has set one of the following
S3 options:
s3_provider=Huawei
s3_ssl_no_verify=1

Author: Andrew Hutchings <andrew@mariadb.org>