btr_cur_instant_init_low(): Accurately parse the metadata record
header for ROW_FORMAT=DYNAMIC and ROW_FORMAT=COMPACT. CHAR columns
used to be unnecessarily written as nonempty strings of bytes.

For ROW_FORMAT=REDUNDANT, we must reserve fixed-length dummy values
for the CHAR columns in the metadata record. This is because in
MariaDB Server 10.4, btr_cur_instant_init_low() will rely on
dict_index_t::trx_id_offset being accurate for the metadata record.

In MariaDB Server 10.4, btr_cur_instant_init_low() assumes that
all PRIMARY KEY columns that are internally variable-length will
be encoded in 0 bytes in the metadata record. Sometimes, CHAR
columns can be encoded as variable-length. We should not
unnecessarily reserve space for a dummy string value in the
metadata record.

Do not fail fi all the partitions were pruned out.

DropIndex, CreateIndex: Remove. The file row0trunc.cc only exists
in MariaDB Server 10.3 so that the crash recovery of TRUNCATE TABLE
operations from older 10.2 and 10.3 servers will work. This dead code
was being used for implementing the MySQL 5.7 WL#6501 TRUNCATE TABLE
that was replaced with a backup-safe implementation in MDEV-13564.

buf_read_ibuf_merge_pages(): Discard any page numbers that are
outside the current bounds of the tablespace, by invoking the
function ibuf_delete_recs() that was introduced in MDEV-20934.
This could avoid an infinite change buffer merge loop on
innodb_fast_shutdown=0, because normally the change buffer merge
would only be attempted if a page was successfully loaded into
the buffer pool.

dict_drop_index_tree(): Add the parameter trx_t*.
To prevent the DROP TABLE crash, do not invoke btr_free_if_exists()
if the entire .ibd file will be dropped. Thus, we will avoid a crash
if the BTR_SEG_LEAF or BTR_SEG_TOP of the index is corrupted,
and we will also avoid unnecessarily accessing the to-be-dropped
tablespace via the buffer pool.

In MariaDB 10.2, we disable the DROP TABLE fix if innodb_safe_truncate=0,
because the backup-unsafe MySQL 5.7 WL#6501 form of TRUNCATE TABLE
requires that the individual pages be freed inside the tablespace.

When commit 09af00cb
removed the crash-upgrade logic of old TRUNCATE TABLE
from MariaDB 10.2 and 10.3, it actually made the return
value of dict_drop_index_tree() redundant.

Fix partitioning and DS-MRR to work together

- In ha_partition::index_end(): take into account that ha_innobase (and
  other engines using DS-MRR) will have inited=RND when initialized for
  DS-MRR scan.
- In ha_partition::multi_range_read_next(): if the MRR scan is using
  HA_MRR_NO_ASSOCIATION mode, it is not guaranteed that the partition's
  handler will store anything into *range_info.
- In DsMrr_impl::choose_mrr_impl(): ha_partition will inquire partitions
  about how much memory their MRR implementation needs by passing
  *buffer_size=0. DS-MRR code didn't know about this (actually it used
  uint for buffer size calculation and would have an under-flow).
  Returning *buffer_size=0 made ha_partition assume that partitions do
  not need MRR memory and pass the same buffer to each of them.

  Now, this is fixed. If DS-MRR gets *buffer_size=0, it will return
  the amount of buffer space needed, but not more than about
  @@mrr_buffer_size.

* Fix ha_{innobase,maria,myisam}::clone. If ha_partition uses MRR on its
  partitions, and partition use DS-MRR, the code will call handler->clone
  with TABLE (*NOT partition*) name as an argument.
  DS-MRR has no way of knowing the partition name, so the solution was
  to have the ::clone() function for the affected storage engine to ignore
  the name argument and get it elsewhere.

Provide own version of popen/pclose, in attempt to workaround
sporadic erratic behavior of UCRT's one.

using create_w_max_indexes_64.result as a template

Apart from page latches (buf_block_t::lock), mini-transactions
are keeping track of at most one dict_index_t::lock and
fil_space_t::latch at a time, and in a rare case, purge_sys.latch.

Let us introduce interfaces for acquiring an index latch
or a tablespace latch.

In a later version, we may want to introduce mtr_t members
for holding a latched dict_index_t* and fil_space_t*,
and replace the remaining use of mtr_t::m_memo
with std::set<buf_block_t*> or with a map<buf_block_t*,byte*>
pointing to log records.

In the test innodb.instant_alter,4k we would be flagging an error
for too large row size. That error was previously only being reported
if the table was being rebuilt. Thus, this merge is fixing a small
omission in MDEV-11369 (instant ADD COLUMN).

revision-id: 673e253724979fd9fe43a4a22bd7e1b2c3a5269e
Author: Kristian Nielsen

Fix missing memory barrier in wait_for_commit.

The function wait_for_commit::wait_for_prior_commit() has a fast path where it
checks without locks if wakeup_subsequent_commits() has already been called.
This check was missing a memory barrier. The waitee thread does two writes to
variables `waitee' and `wakeup_error', and if the waiting thread sees the
first write it _must_ also see the second or incorrect behavior will occur.
This requires memory barriers between both the writes (release semantics) and
the reads (acquire semantics) of those two variables.

Other accesses to these variables are done under lock or where only one thread
will be accessing them, and can be done without barriers (relaxed semantics).

btr_create(), btr_root_raise_and_insert(): Write a MLOG_MEMSET record
to set FIL_PAGE_PREV,FIL_PAGE_NEXT to FIL_NULL, instead of writing
two MLOG_4BYTES records.

For ROW_FORMAT=COMPRESSED pages, we will not use MLOG_MEMSET
because we want the crash-downgrade to earlier 10.4 releases to succeed.

mlog_parse_nbytes(): Relax the too strict assertion. There is no problem
with MLOG_MEMSET records that affect the uncompressed header of
ROW_FORMAT=COMPRESSED index pages.

Fix incorrect change introduced in the fix for MDEV-20109.

The patch tried to compute a more precise estimate for the record_count
value in SJ-Materialization-Scan strategy (in
Sj_materialization_picker::check_qep).  However the new formula is worse
as it produces extremely optimistic results in common cases where
SJ-Materialization-Scan should be used)

The old formula produces pessimistic results in cases when Sj-Materialization-
Scan is unlikely to be a good choice anyway. So, the old behavior is better.

Move row size check to early CREATE/ALTER TABLE phase. Stop checking
on table open.

dict_index_add_to_cache(): remove parameter 'strict', stop checking row size

dict_index_t::record_size_info_t: this is a result of row size check operation

create_table_info_t::row_size_is_acceptable(): performs row size check.
Issues error or warning. Writes first overflow field to InnoDB log.

create_table_info_t::create_table(): add row size check

dict_index_t::record_size_info(): this is a refactored version
of dict_index_t::rec_potentially_too_big(). New version doesn't change global
state of a program but return all interesting info. And it's callers who
decide how to handle row size overflow.

dict_index_t::rec_potentially_too_big(): removed

memo_block_unfix(), memo_latch_release(): Merge to ReleaseLatches.

memo_slot_release(), ReleaseAll: Clean up the formatting.

A search with PAGE_CUR_GE may land on the supremum record on
a leaf page that is not the rightmost leaf page.
This could occur when all keys on the current page are
smaller than the search key, and the smallest key on the
successor page is larger than the search key.

ibuf_delete_recs(): Correct the debug assertion accordingly.

Basically, use more List<T>::iterator. This patch required adding two more
overloads to new iterator for convenience.

It's just added regression tests.

Closes #1407

mtr_t::Impl, mtr_t::Command: Merge to mtr_t.

MTR_MAGIC_N: Remove.

MTR_STATE_COMMITTING: Remove. This state was only being set
internally during mtr_t::commit().

mtr_t::Command::m_locks_released: Remove (set-and-never-read member).

mtr_t::Command::m_start_lsn: Replaced with the return value of
finish_write() and a parameter to release_blocks().

mtr_t::Command::m_end_lsn: Removed as a duplicate of mtr_t::m_commit_lsn.

mtr_t::Command::prepare_write(): Replace a switch () with a
comparison against 0. Only 2 m_log_mode are allowed.

Avoid creating std::vector, and use single instead of double traversal.

Problem:
========
CURRENT_TEST: binlog_encryption.rpl_corruption

mysqltest: In included file "./include/wait_for_slave_io_error.inc":
...
At line 72: Slave stopped with wrong error code
**** Slave stopped with wrong error code: 1743 (expected 1595,1913) ****

Analysis:
========
The test emulates the corruption at the various stages of replication for
example in binlog file, in network and in relay log etc. It verifies that all
corruption cases are handled through appropriate error messages.

The test cases which emulate network failure expect following errors.
--ER_SLAVE_RELAY_LOG_WRITE_FAILURE (1595)
--ER_NETWORK_READ_EVENT_CHECKSUM_FAILURE (1743)

Ideally test should expect error codes as 1595 and 1743.
But the test actually waits on incorrect error code 1595,1913

Fix:
===
Added appropriate error code for 'ER_NETWORK_READ_EVENT_CHECKSUM_FAILURE'.
Replaced 1913 with 1743.

New iterator has the fastest possible implementation: just moves one pointer.
It's faster that List_iterator and List_iterator_fast: both do more on increment.

Overall patch brings:
1) work compile times
2) possibly(!) worse debug build performance
3) definitely better optimized build performance
4) ability to write less code
5) ability to write less bug-prone code