Problem:
========
Truncate operation holds MDL on the table (t1) and tries to
acquire InnoDB dict_operation_lock. Purge holds dict_operation_lock
and tries to acquire MDL on the table (t1) to evaluate virtual
column expressions for indexed virtual columns.
It leads to deadlock of purge and truncate table (DDL).

Solution:
=========
If purge tries to acquire MDL on the table then it should do the following:

i) Purge should release all innodb latches (including dict_operation_lock)
before acquiring metadata lock on the table.

ii) After acquiring metadata lock on the table, it should check whether the
table was dropped or renamed. If the table is dropped then purge should
ignore the undo log record. If the table is renamed then it should
release the old MDL and acquire MDL on the new name.

iii) Once purge acquires MDL, it should use the SQL table handle for all
the remaining virtual index for the purge record.

purge_node_t: Introduce new virtual column information to know whether
the MDL was acquired successfully.

This is joint work with Marko Mäkelä.

Add an explicit redo log flush. In this test
innodb_flush_log_at_trx_commit was 2 by default.
It is also possible that this failure occurs because of MDEV-15740.

1. The changed variant did not fail without the patch for MDEV-16629
while the original test case did fail.
2. In any case the test case should go to cte_recursive_not_embedded.test
that was not created yet.

At the end of a test, 'connection default' should be in a usable state.
This was not the case, because there was a preceding 'send' without a
'reap'. If 'reap' was added, an error would be reported because the
server was restarted after the 'send'. It is easiest to 'send' from a
separate connection and do the restart from 'connection default'.

Make dict_table_t::n_ref_count private, and protect it with
a combination of dict_sys->mutex and atomics. We want to be
able to invoke dict_table_t::release() without holding
dict_sys->mutex.

When processing a query containing with clauses a call of the function
check_dependencies_in_with_clauses() before opening tables used in the
query is necessary if with clauses include specifications of recursive
CTEs.
This call was missing if such a query belonged to a stored function.
This caused misbehavior of the server: it could report a fake error
as in the test case for MDEV-16629 or the executed query could hang
as in the test cases for MDEV-16661 and MDEV-15151.

Marko mentions, it could be caused by  MDEV-15740 where InnoDB does not
flush redo log as often as it should, with innodb_flush_log_at_trx_commit=1

The workaround is to use innodb_flush_log_at_trx_commit=2, which,
according to MDEV-15740 is more durable.

One can create table with the same name for `field` and `table` `check` constraint.
For example:
`create table t(a int check(a>0), constraint a check(a>10));`
But when inserting new rows same error is always raised.
For example with
```insert into t values (-1);```
and
```insert into t values (10);```
same error `ER_CONSTRAINT_FAILED` is obtained and it is not clear which constraint is violated.
This patch solve this error so that in case if field constraint is violated the first parameter
in the error message is `table.field_name` and if table constraint is violated the first parameter
in error message is `constraint_name`.

use OPEN_ALWAYS instead, since we know file already exist.

Disks with native 4K sectors need 4K alignment and size for  unbuffered IO
(i.e for files opened with FILE_FLAG_NO_BUFFERING)

Innodb opens redo log with FILE_FLAG_NO_BUFFERING, however it always does
512byte IOs. Thus, the IO on 4K native sectors will fail, rendering
Innodb non-functional.

The fix is to check whether OS_FILE_LOG_BLOCK_SIZE is multiple of logical
sector size, and if it is not, reopen the redo log without
FILE_FLAG_NO_BUFFERING flag.

Use GetLastError() instead.

table->in_use is not always set and a KILL signal can arrive anytime.

MDEV-7257 made a dump thread to read from binlog concurrently with
writers as long as the read bytes are below a water-mark
(MYSQL_BIN_LOG::binlog_end_pos). However it appeared to be possible a
dump thread reader reach out for bytes past the water mark through a
feature of IO_CACHE that fills in the internal buffer and while doing
so it could read what the reader is not supposed to see (the bytes
above MYSQL_BIN_LOG::binlog_end_pos).

The issue is fixed with constraining the IO_CACHE buffer fill to respect
the watermark.

An added unit test proves reading from file is bound to an external
parameter
passed to {IO_CACHE::end_of_file} cache member.

rnd_pos_by_record calls ha_rnd_pos, which does the counting

MDEV-7257 made a dump thread to read from binlog concurrently with
writers as long as the read bytes are below a water-mark
(MYSQL_BIN_LOG::binlog_end_pos). However it appeared to be possible a
dump thread reader reach out for bytes past the water mark through a
feature of IO_CACHE that fills in the internal buffer and while doing
so it could read what the reader is not supposed to see (the bytes
above MYSQL_BIN_LOG::binlog_end_pos).

The issue is fixed with constraining the IO_CACHE buffer fill to respect
the watermark.

An added unit test proves reading from file is bound to an external
parameter
passed to {IO_CACHE::end_of_file} cache member.

Different fix, just use NULL, not no_db,

The previous correction of the patch for mdev-16473 did not work
correctly for the databases whose names started with '*'.
Added a test case with a database named "*".

Only close stdin if it was open initinally. Otherwise we may close file
descriptor which is reused for different puprose (specifically for binlog
index file in case of this bug).

This is a typical systemd response where it tries to shutdown the
joiner (due to "timeout") before the joiner manages to complete SST.

wsrep_sst_wait
wsrep_SE_init_wait
	While waiting the operation to finish use mysql_cond_timedwait
	instead of mysql_cond_wait and if operation is not finished
	extend systemd timeout (if needed).

dict0dict.cc

buf_LRU_drop_page_hash_for_tablespace(): Return whether any adaptive
hash index entries existed. If yes, the caller should keep retrying to
drop the adaptive hash index.

row_import_for_mysql(), row_truncate_table_for_mysql(),
row_drop_table_for_mysql(): Ensure that the adaptive hash index was
entirely dropped for the table.

MDEV-15953 Alter InnoDB Partitioned Table Moves Files (which were originally not in the datadir) to the datadir

ha_innobase::prepare_inplace_alter_table: preserve DATA DICTIONARY for table

Before this patch if no default database was set the server threw
an error for any table name reference that was not fully qualified by
database name. In particular it happened for table names referenced
CTE tables. This was incorrect.
The error message was thrown at the parser stage when the names referencing
different tables were not resolved yet.
Now if no default database is set and  a with clause is used in the
processed statement  any table reference is just supplied with a dummy
database name "*none*" at the parser stage. Later after a call
of check_dependencies_in_with_clauses() when the names for CTE tables
can be resolved error messages are thrown only for those names that
refer to non-CTE tables. This is done in open_and_process_table().

register changes of last_gtid

Observed and described
partitioned engine execution time difference
between master and slave was caused by excessive invocation
of base_engine::rnd_init which was done also for partitions
uninvolved into Rows-event operation.
The bug's slave slowdown therefore scales with the number of partitions.

Fixed with applying an upstream patch.

References:
----------
https://bugs.mysql.com/bug.php?id=73648
Bug#25687813 REPLICATION REGRESSION WITH RBR AND PARTITIONED TABLES