In commit f80deb95 (MDEV-27868)
a fix for a correctness regression caused a performance regression
by increasing the amount of work that is executed while holding
buf_pool.flush_list_mutex.

buf_page_t::set_temp_modified(): Relax an assertion, to allow an
already dirty block to be marked as dirty.

buf_page_t::flush_list_requests: Note that the variable is not
always protected by buf_pool.flush_list_mutex. Already dirty blocks
that are being written to will increment the counter without
holding buf_pool.flush_list_mutex.

mtr_t::process_freed_pages(): Handle pages that were freed during
the execution of the mini-transaction.

ReleaseUnlogged, mtr_t::release_unlogged(): Release modified pages when
no log was written. This is for pages of the temporary tablespace, or for
IMPORT TABLESPACE.

ReleaseModified: Renamed from ReleaseBlocks.
Assume that buf_pool.flush_list_mutex was acquired by the caller.

ReleaseSimple: A combination of ReleaseLatches and ReleaseModified,
for the case that for any modified pages, some earlier modifications
are already waiting to be written.

mtr_t::commit(): Invoke one of release_unlogged(), ReleaseModified,
ReleaseSimple, ReleaseAll. Acquire and release buf_pool.flush_list_mutex
at most once.

memo_slot_release(): Simplify the code.

mtr_t::sx_latch_at_savepoint(), mtr_t::x_latch_at_savepoint():
Reduce the size of the critical section.

fil_space_t::update_last_freed_lsn(), fil_space_t::clear_freed_ranges(),
fil_space_t::add_free_range(): Assume that freed_range_mutex is held
by the caller.

buf_pool_t::prepare_insert_into_flush_list(): Determine the insert
position for buf_pool_t::insert_into_flush_list(). Remove any clean
blocks from buf_pool.flush_list that were encountered while searching.

buf_pool_t::insert_into_flush_list(): Insert the block at the
predetermined position.

A subsequently executed test could fail due to warning messages
that some mysql.help_% tables were not closed properly.

We do not want subsequent test executions to fail due to messages
about mysql.help_% tables needing recovery.

Thanks to Sergei Golubchik for noticing this.

Reading the last page of table with "dynamic page" format would generate
an error when reading after the last row. This was never noticed as
when using Aria as a handler any error messages generated by
_ma_set_fatal_error() was ignored.

If we got a read error from S3, we did not signal threads waiting
to read blocks in the read-range. This caused these threads to
hang forever.

There is still one issue left that the S3 error will be logged as an
'table is crashed' error instead of the IO error. This will be fixed
by a larger patch in 10.6 that improves error reporting from Aria.

There is no test case for this as it is very hard to repeat.
I tested this with a patch that causes random read failures in S3
used perl multi-threaded test with 8 threads to simulate reads.
This patch fixes all found hangs.

We will introduce an optional log record OPT_PAGE_CHECKSUM for recording
page checksums, so that more inconsistencies on crash recovery may be
caught.

mtr_t::page_checksum(const buf_page_t&): Write OPT_PAGE_CHECKSUM
(currently not for ROW_FORMAT=COMPRESSED pages).

mtr_t::do_write(): Write OPT_PAGE_CHECKSUM records for all pages
(currently, in debug builds only).

mtr_t::is_logged(): Return whether log should be written.

mtr_t::set_log_mode_sub(const mtr_t&): Set the logging mode of
a sub-minitransaction when another mini-transaction is holding
latches on some modified pages. When creating or freeing BLOB pages,
we may only write OPT_PAGE_CHECKSUM records in the main mini-transaction,
after all changes have been written to the log.

MTR_LOG_SUB: Log mode for a sub-mini-transaction.

mtr_t::free(): Define non-inline, and invoke MarkFreed.

MarkFreed: For any matching page in the mini-transaction log,
change the first entry to say MTR_MEMO_PAGE_X_MODIFY and any subsequent
entries to MTR_MEMO_PAGE_X_FIX.

FindModified: Simplify a condition. MTR_MEMO_MODIFY can only be set
if MTR_MEMO_PAGE_X_FIX or MTR_MEMO_PAGE_SX_FIX are set.

FindBlockX: Consider also MTR_MEMO_PAGE_X_MODIFY.

recv_sys_t::parse(): Store OPT_PAGE_CHECKSUM records.

log_phys_t::apply(): Validate OPT_PAGE_CHECKSUM records.

log_phys_t::page_checksum(): Validate an OPT_PAGE_CHECKSUM record.

Tested by: Matthias Leich

--debug-dbug=d,intermittent_read_failure is effective after the
database has been started up.

--debug-dbug=d,intermittent_recovery_failure is always effective,
including during recovery.

The approach to handling corruption that was chosen by Oracle in
commit 177d8b0c
is not really useful. Not only did it actually fail to prevent InnoDB
from crashing, but it is making things worse by blocking attempts to
rescue data from or rebuild a partially readable table.

We will try to prevent crashes in a different way: by propagating
errors up the call stack. We will never mark the clustered index
persistently corrupted, so that data recovery may be attempted by
reading from the table, or by rebuilding the table.

This should also fix MDEV-13680 (crash on btr_page_alloc() failure);
it was extensively tested with innodb_file_per_table=0 and a
non-autoextend system tablespace.

We should now avoid crashes in many cases, such as when a page
cannot be read or allocated, or an inconsistency is detected when
attempting to update multiple pages. We will not crash on double-free,
such as on the recovery of DDL in system tablespace in case something
was corrupted.

Crashes on corrupted data are still possible. The fault injection mechanism
that is introduced in the subsequent commit may help catch more of them.

buf_page_import_corrupt_failure: Remove the fault injection, and instead
corrupt some pages using Perl code in the tests.

btr_cur_pessimistic_insert(): Always reserve extents (except for the
change buffer), in order to prevent a subsequent allocation failure.

btr_pcur_open_at_rnd_pos(): Merged to the only caller ibuf_merge_pages().

btr_assert_not_corrupted(), btr_corruption_report(): Remove.
Similar checks are already part of btr_block_get().

FSEG_MAGIC_N_BYTES: Replaces FSEG_MAGIC_N_VALUE.

dict_hdr_get(), trx_rsegf_get_new(), trx_undo_page_get(),
trx_undo_page_get_s_latched(): Replaced with error-checking calls.

trx_rseg_t::get(mtr_t*): Replaces trx_rsegf_get().

trx_rseg_header_create(): Let the caller update the TRX_SYS page if needed.

trx_sys_create_sys_pages(): Merged with trx_sysf_create().

dict_check_tablespaces_and_store_max_id(): Do not access
DICT_HDR_MAX_SPACE_ID, because it was already recovered in dict_boot().
Merge dict_check_sys_tables() with this function.

dir_pathname(): Replaces os_file_make_new_pathname().

row_undo_ins_remove_sec(): Do not modify the undo page by adding
a terminating NUL byte to the record.

btr_decryption_failed(): Report decryption failures

dict_set_corrupted_by_space(), dict_set_encrypted_by_space(),
dict_set_corrupted_index_cache_only(): Remove.

dict_set_corrupted(): Remove the constant parameter dict_locked=false.
Never flag the clustered index corrupted in SYS_INDEXES, because
that would deny further access to the table. It might be possible to
repair the table by executing ALTER TABLE or OPTIMIZE TABLE, in case
no B-tree leaf page is corrupted.

dict_table_skip_corrupt_index(), dict_table_next_uncorrupted_index(),
row_purge_skip_uncommitted_virtual_index(): Remove, and refactor
the callers to read dict_index_t::type only once.

dict_table_is_corrupted(): Remove.

dict_index_t::is_btree(): Determine if the index is a valid B-tree.

BUF_GET_NO_LATCH, BUF_EVICT_IF_IN_POOL: Remove.

UNIV_BTR_DEBUG: Remove. Any inconsistency will no longer trigger
assertion failures, but error codes being returned.

buf_corrupt_page_release(): Replaced with a direct call to
buf_pool.corrupted_evict().

fil_invalid_page_access_msg(): Never crash on an invalid read;
let the caller of buf_page_get_gen() decide.

btr_pcur_t::restore_position(): Propagate failure status to the caller
by returning CORRUPTED.

opt_search_plan_for_table(): Simplify the code.

row_purge_del_mark(), row_purge_upd_exist_or_extern_func(),
row_undo_ins_remove_sec_rec(), row_undo_mod_upd_del_sec(),
row_undo_mod_del_mark_sec(): Avoid mem_heap_create()/mem_heap_free()
when no secondary indexes exist.

row_undo_mod_upd_exist_sec(): Simplify the code.

row_upd_clust_step(), dict_load_table_one(): Return DB_TABLE_CORRUPT
if the clustered index (and therefore the table) is corrupted, similar
to what we do in row_insert_for_mysql().

fut_get_ptr(): Replace with buf_page_get_gen() calls.

buf_page_get_gen(): Return nullptr and *err=DB_CORRUPTION
if the page is marked as freed. For other modes than
BUF_GET_POSSIBLY_FREED or BUF_PEEK_IF_IN_POOL this will
trigger a debug assertion failure. For BUF_GET_POSSIBLY_FREED,
we will return nullptr for freed pages, so that the callers
can be simplified. The purge of transaction history will be
a new user of BUF_GET_POSSIBLY_FREED, to avoid crashes on
corrupted data.

buf_page_get_low(): Never crash on a corrupted page, but simply
return nullptr.

fseg_page_is_allocated(): Replaces fseg_page_is_free().

fts_drop_common_tables(): Return an error if the transaction
was rolled back.

fil_space_t::set_corrupted(): Report a tablespace as corrupted if
it was not reported already.

fil_space_t::io(): Invoke fil_space_t::set_corrupted() to report
out-of-bounds page access or other errors.

Clean up mtr_t::page_lock()

buf_page_get_low(): Validate the page identifier (to check for
recently read corrupted pages) after acquiring the page latch.

buf_page_t::read_complete(): Flag uninitialized (all-zero) pages
with DB_FAIL. Return DB_PAGE_CORRUPTED on page number mismatch.

mtr_t::defer_drop_ahi(): Renamed from mtr_defer_drop_ahi().

recv_sys_t::free_corrupted_page(): Only set_corrupt_fs()
if any log records exist for the page. We do not mind if read-ahead
produces corrupted (or all-zero) pages that were not actually needed
during recovery.

recv_recover_page(): Return whether the operation succeeded.

recv_sys_t::recover_low(): Simplify the logic. Check for recovery error.

Thanks to Matthias Leich for testing this extensively and to the
authors of https://rr-project.org for making it easy to diagnose
and fix any failures that were found during the testing.

The types btr_latch_mode and mtr_memo_type_t are partly derived from
rw_lock_type_t. Despite that, some code for converting between them
is using conditions instead of bitwise arithmetics.

Let us define btr_latch_mode in such a way that more conversions to
rw_lock_type_t are possible by bitwise and.

Some SPATIAL INDEX code that assumed !(BTR_MODIFY_TREE & BTR_MODIFY_LEAF)
was adjusted.

fil_space_t::is_freed(): Check if a page is in freed_ranges.

fil_space_t::flush_freed(): Replaces buf_flush_freed_pages().

This was broken in 54e2e701 (MDEV-25524).

btr_page_split_and_insert(): Declare all parameters nonnull.
btr_pessimistic_scrub() was removed
in commit a5584b13 (MDEV-15528).

This is a 10.5 version of the patch.

This is a 10.7 version of the patch.

mtr_t::modify(): Set the m_made_dirty flag if needed,
so that buf_pool_t::insert_into_flush_list() will be invoked
while holding log_sys.flush_order_mutex.

This is something that was should have been part of
commit b212f1da (MDEV-22107).

mtr_t::is_empty(): Replaces mtr_t::get_log() and mtr_t::get_memo().

mtr_t::get_log_size(): Replaces mtr_t::get_log().

mtr_t::print(): Remove, unused function.

ReleaseBlocks::ReleaseBlocks(): Remove an unused parameter.

Reviewed by: Nayuta Yanagisawa

Fixup

Accept JSON values for the JSON fields.

- Fixed wrong DBUG_ASSERT when waiting for big-block-read
- Update S3_pagecache_reads counter when reading a block from S3.
  Before this patch the variable value was always 0

Reviewer: Oleksandr Byelkin <sanja@mariadb.com>

The assert happens in 10.6 with the following command:

./mtr --no-reorder --verbose-restart main.update_ignore_216 main.upgrade_MDEV-19650 main.upgrade_MDEV-23102-1 main.upgrade_MDEV-23102-2 main.upgrade_geometrycolumn_procedure_definer main.upgrade_mdev_24363 main.varbinary sys_vars.aria_log_file_size_basic

Reviewer: Oleksandr Byelkin <sanja@mariadb.com>