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.

In InnoDB, an INSERT will not create an explicit lock object. Instead,
the inserted record is initially implicitly locked by the transaction
that wrote its trx_t::id to the hidden system column DB_TRX_ID.
(Other transactions would check if DB_TRX_ID is referring to a
transaction that has not been committed.)

If a record was inserted in the current transaction, it would be
implicitly locked by that transaction. Only if some other transaction
is requesting access to the record, the implicit lock should be
converted to an explicit one, so that the waits-for graph can be
constructed for detecting deadlocks and lock wait timeouts.

Before this fix, InnoDB would convert implicit locks to
explicit ones, even if no conflict exists.

lock_rec_convert_impl_to_expl(): Return whether caller_trx
already holds an explicit lock that covers the record.

row_vers_impl_x_locked_low(): Avoid a lookup if the record matches
caller_trx->id.

lock_trx_has_expl_x_lock(): Renamed from lock_trx_has_rec_x_lock().

row_upd_clust_step(): In a debug assertion, check for implicit lock
before invoking lock_trx_has_expl_x_lock().

rw_trx_hash_t::find(): Make do_ref_count a mandatory parameter.
Assert that trx_id is not 0 (the caller should check it).

trx_sys_t::is_registered(): Only invoke find() if id != 0.

trx_sys_t::find(): Add the optional parameter do_ref_count.

lock_rec_queue_validate(): Avoid lookup for trx_id == 0.

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.

For some reason, some of these suppressions would fail to suppress
when the code is compiled with clang 6.0, Debug and -DWITH_ASAN=ON.
Possibly it is related to the number of .* or the length of the
regular expression strings.

Before attempting to create an index, copy any fields from
dict_table_t, because the table would be freed after a failed
index creation.

	NULL values when there is no DEFAULT

- Merged the alter_non_null test case to alter_not_null test case.
Renamed the alter_non_null_debug to alter_not_null_debug test case

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`.

Correct 898a8c3c to work when newer debhelper-10.2 is installed from
xenial-backports (or jessie-backports).

Use gcc version instead of debproxy version, this is likely a gcc
issue (as disabling LTO and gcc's linker plugin fixes it).

use OPEN_ALWAYS instead, since we know file already exist.

* ignore CHECK constraint for historical rows;
* FOREIGN KEY test case.

TODO:
MDEV-16301 IB: use real table name for error messages on ALTER

Closes tempesta-tech/mariadb#491
Closes #748

MDEV-15947 ASAN heap-use-after-free in Item_ident::print or in my_strcasecmp_utf8 or unexpected ER_BAD_FIELD_ERROR upon call of stored procedure reading from versioned table

Closes #728

MDEV-15645 Assertion `table->insert_values' failed in write_record upon REPLACE into a view with underlying versioned table

Right temporary storage for system versioning operations is table->record[2],
not table->insert_values

Closes #712

RBR not versioned -> versioned

do it for all write_row events, not only for WRITE_ROWS_EVENT_V1

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.

Building this plugin which requires run-time access to network, uses a lot
of disk space and is slow was already partially disabled. This way we
also ensure that on cmake level it never runs even if it out of some
autodetection reason at times thought it could run.

This fixes the error message:
  fatal: unable to access 'https://github.com/awslabs/aws-sdk-cpp.git/':
  Problem with the SSL CA cert (path? access rights?)

Fixes errors on Travis like:
  cp: error writing debian/libmariadbd19//usr/lib/x86_64-linux-gnu/
  libmariadbd.so.19: No space left on device

This complements commit ecb0e0ad that
disabled a bunch of plugins from being built on Travis-CI (due to time
and disk space saving reasons).

When the plugins are not built, the packaging phase will fail due to
missing files. This change omits the files from packaging to the process
can complete successfully.

* Exclude some storage engines from Travis to conserve
  build time and disk usage per job. Exluded:
  TOKUDB MROONGA SPIDER OQGRAPH PERFSCHEMA SPHINX
* Increase travis_wait from default 20m to 30 for MTR
* Use travis_wait for long running MTR command (wait
  30m instead of default 20m)
* Increase testcase-timeout to 20m for OSX, 2m for Linux
* Set ccache size only on Linux, adjust timeout again
* Increase cache push timeout to 5 mins
* Remove AWS defines, not needed
* Remove commented out ASAN rules, has been disabled
  previously since it has a significant impact on job
  runtime, should be used more in buildbot instead
* Misc cleanup and fixes