- Error on commit now returns HA_ERR_COMMIT_ERROR instead of
  HA_ERR_INTERNAL_ERROR
- If checkpoint fails, it will now print out where it failed.

The debian/salsa-ci.yml used to work also on upstream MariaDB.org branches,
but has recently regressed and several jobs stopped working. These fixes
are necessary to get it working again.

* Partially revert 8642f592 that never worked, as MariaDB 10.2 does not
  have a mysql.global table nor a mariadb.sys user. Those features weren't
  introduced until MariaDB 10.4.

* Partially revert 0268b871 as we don't want ColumnStore as part of the
  native Debian build. It should build only when the build is triggered
  via autobake-deb.sh (MariaDB.org builds).

* Adjust salsa-ci.yml to cope with various Stretch to Sid upgrade issues
  and remove the legacy mariadb-connector-c job completely as that package
  hasn't been around for years anymore.

* Extend Lintian overrides to be otherwise Lintian clean

set_item() uses 1UL << bit, so is_set_item() must do the same.

This fixes sporadic perfschema.show_aggregate failures
(sporadic, because `bit` is the thread id, so depending on how many
tests were run before perfschema.show_aggregate it can be above or
below 32).

# Conflicts:
#	appveyor.yml

# Conflicts:
#	cmake/os/Windows.cmake
#	sql/sql_yacc.yy

A conversion warning 4267 that we want to disable(prior to 10.3),
was suppressed with  cmake VS generator for C++ and C, despite being set
only for CXX flags.

The fix is to disable the warning in C flags, too. In 10.2, this warning
is noisy, in 10.3 it is fixed.

instead, include handler_rollback in the following per-connection selects

The merge accidentally
omitted the 10.4 commit 472b35c7 and
reverted the 10.5 commit 6e3bd663.

Apply 115fec58 to 10.5

The st_blksize returned by fstat(2) is not documented to be
a power of 2, like we assumed in
commit 58252fff (MDEV-26040).
While on Linux, the st_blksize appears to report the file system
block size (which hopefully is not smaller than the sector size
of the underlying block device), on FreeBSD we observed
st_blksize values that might have been something similar to st_size.

Also IBM AIX was affected by this. A simple test case would
lead to a crash when using the minimum innodb_buffer_pool_size=5m
on both FreeBSD and AIX:

seq -f 'create table t%g engine=innodb select * from seq_1_to_200000;' \
1 100|mysql test&
seq -f 'create table u%g engine=innodb select * from seq_1_to_200000;' \
1 100|mysql test&

We will fix this by not trusting st_blksize at all, and assuming that
the smallest allowed write size (for O_DIRECT) is 4096 bytes. We hope
that no storage systems with larger block size exist. Anything larger
than 4096 bytes should be unlikely, given that it is the minimum
virtual memory page size of many contemporary processors.

MariaDB Server on Microsoft Windows was not affected by this.

While the 512-byte sector size of the venerable Seagate ST-225 is still
in widespread use, the minimum innodb_page_size is 4096 bytes, and
innodb_log_file_size can be set in integer multiples of 65536 bytes.

The only occasion where InnoDB uses smaller data file block sizes than
4096 bytes is with ROW_FORMAT=COMPRESSED tables with KEY_BLOCK_SIZE=1
or KEY_BLOCK_SIZE=2 (or innodb_page_size=4096). For such tables,
we will from now on preallocate space in integer multiples of 4096 bytes
and let regular writes extend the file by 1024, 2048, or 3072 bytes.

The view INFORMATION_SCHEMA.INNODB_SYS_TABLESPACES.FS_BLOCK_SIZE
should report the raw st_blksize.

For page_compressed tables, the function fil_space_get_block_size()
will map to 512 any st_blksize value that is larger than 4096.

os_file_set_size(): Assume that the file system block size is 4096 bytes,
and only support extending files to integer multiples of 4096 bytes.

fil_space_extend_must_retry(): Round down the preallocation size to
an integer multiple of 4096 bytes.

Cover all columns that did not have comments. Adjust docs based off of
MariaDB implementation.

Improve documentation of performance_schema tables by appending COLUMN
comments to tables. Additionally improve test coverage and update corresponding
tests.

This is part of the patch covering newer columns and tables in 10.5.

FTS indexes has a prefix_len=1 or prefix_len=0 as stated by comment in
mysql_prepare_create_table().

Thus, a newly added assertion should be relaxed for FTS indexes.

Any modification of buf_pool.page_hash is supposed to be protected
by buf_pool.mutex and page_hash_latch::write_lock(). The buffer pool
watch mechanism of the InnoDB change buffer was violating that
ever since commit b1ab211d (MDEV-15053).

buf_pool_t::watch_set(): Extend the critical section of buf_pool.mutex.

buf_pool_t::watch_unset(): Define non-inline, because
calls are infrequent and this function became larger.
If we have to detach a sentinel from page_hash,
do it while holding both the mutex and the exclusive hash latch.

buf_pool_t::watch_remove(): Assert that the mutex is being held.

buf_page_init_for_read(): Remove some work-arounds for
previously encountered race conditions related to buf_pool.watch.

Bug happens when partially indexed CHAR or VARCHAR field in converted from
utf8mb3 to utf8mb4.

Fixing by relaxing assertions. For some time dict_index_t and dict_table_t
are becoming not synchronized. Namely, dict_index_t has a new prefix_len which
is a multiple of a user-provided length and charset->mbmaxlen. But
the table still have and old mbmaxlen and assertion fails. This happens only
during utf8mb3 -> utf8mb4 conversions and the magic number 4 comes from
utf8mb_4_.

At the end of ALTER TABLE (innobase_rename_or_enlarge_columns_cache())
dict_index_t and dict_table_t became synchronized
again and will stay so at all times. For, example, they will be synchronized
on table load and newly added assertion proves that.