In Debian official the MariaDB plugins (.so files) go to a separate
versioned directory so that upgrades and dependencies will work correctly.

This change extends this script to check the /usr/lib/*/mariadb19/..
directory in addition to what it already does. Without this change
the script fails with:

  $ mysql_install_db ...
  Cannot change ownership of the '/auth_pam_tool_dir' directory
  to the 'mysql' user. Check that you have the necessary permissions and
  try again.

- Update comment strings
- Extend package description to satisfy Lintian complaint
- Remove uscan stanza from rules as it is never used anyway

MDEV-20423 Assertion `0' failed or `btr_validate_index(index, 0, false)' in row_upd_sec_index_entry or error code 126: Index is corrupted upon DELETE with TIME_ROUND_FRACTIONAL

- Fixes a situation in which a thread gets BF aborted and does not send the reply back to
  the client, even though the connection is still alive. That caused
  both sides to hang waiting for the next message. Now we explicitly
  check that the connection is still alive.
- MTR test for the above
- Replaced thd->killed assignments to thd->reset_kill_query where applicable.

Command COM_SHUTDOWN was rejected in non-Primary because
server_command_flags[COM_SHUTDOWN] had value CF_NO_COM_MULTI
instead of CF_SKIP_WSREP_CHECK.

As a fix removed assignment
server_command_flags[CF_NO_COM_MULTI]= CF_NO_COM_MULTI
which overwrote server_command_flags[COM_SHUTDOWN].

MDEV-20228 `mysql_upgrade` fails on every version upgrade: "ERROR 1267 (HY000) at line 7: Illegal mix of collations (utf8mb4_unicode_ci,COERCIBLE) and (utf8mb4_general_ci,COERCIBLE) for operation 'like'"

MDEV-18153 Assertion `0' or Assertion `btr_validate_index(index, 0)' failed in row_upd_sec_index_entry or error code 126: Index is corrupted upon UPDATE with TIME_ROUND_FRACTIONAL

Conversion to a temporal data type resulting into a lower precision
depends on TIME_ROUND_FRACTIONAL. Taking into account this dependency in:
- indexed generated virtual column expressions
- persistent virtual column expressions

A warning is now issued if conversion from the generation expression
to the column data type depends on TIME_ROUND_FRACTIONAL.

The warning will be changed to error in 10.5

Followup patch: fix typos

innobase_rename_or_enlarge_column_try(): Relax a debug assertion.
The DATA_VERSIONED bits in dict_col_t::prtype do not affect the
storage format.

Fixed 4-byte length characters handled incorrectly.

Problem was that if user used bad wsrep configuration
we call unireg_abort and in wsrep case there is check
to wsrep_server_state that might not yet be initialized.
Fixed by checking that wsrep_server_state is initialized
before checking it's state.

Changes to be committed:
	modified:   sql/mysqld.cc
	modified:   sql/wsrep_server_state.h

In mysql-server/commit@f46329044f8618212923bdf52e15d5b464201edc
the InnoDB function btr_cur_open_at_rnd_pos() was corrected so that
it would return a status that indicates whether the cursor was
successfully positioned. But this change was not correctly merged to
MariaDB in 2e814d47.

btr_cur_open_at_rnd_pos(): In the code path that was introduced in
MDEV-8588, properly return failure status.

No deterministic test case was found for this failure.
It was caught after removing the function
page_copy_rec_list_end_to_created_page() in a development branch.
As a result, the fill factor of index trees would improve, and
supposedly, so would the probability of btr_cur_open_at_rnd_pos()
reaching the intentionally corrupted page in the test
innodb.leaf_page_corrupted_during_recovery.
The wrong return value would cause
btr_estimate_number_of_different_key_vals() to wrongly invoke
btr_rec_get_externally_stored_len() on a non-leaf page and
trigger an assertion failure at the start of that function.

- During trx_undo_report_rename(), InnoDB can fail to write undo log
for it if undo log doesn't fit in the undo page. In that case, InnoDB
adds one more undo log page and retry to write the rename undo log.
But the assert is wrong and it doesn't allow to fail even for one time.

Null merge the MDEV-14383 fix; it affects 5.5 only.

Also added comments for trace_plan_prefix and the class Json_writer_temp_disable

Added:
      1) estimated_join_cardinality
      2) best_chosen_access_method for a table
      3) best_join_order

there was a SELECT/DELETE race

Files for PAGE_COMPRESSED tables that were created with
innodb_checksum_algorithm=full_crc32 store the value of
innodb_compression_algorithm at the time of the file creation.

The server-wide setting of innodb_compression_algorithm
may be changed after file creation. We must ignore any mismatch
when opening a data file, and for writes, we must use the
choice of algorithm that is stored in the file.

fil_space_t::is_flags_full_crc32_equal(): Ignore the
innodb_compression_algorithm but do compare innodb_page_size.

fil_space_t::is_flags_non_full_crc32_equal(): Ignore the
innodb_compression_algorithm.

The test mariabackup.encrypted_page_corruption was hard-wired
for innodb_checksum_algorithm=crc32. Enable a combination for
full_crc32 for the sake of completeness.