Fixed typo on select that is executed only when something unexpected
happens.

MDEV-12632: Source and destination overlap in memcpy, encryption.innodb-discard-import-change fails in buildbot with valgrind

Use block->page.offset for checking page number.

Problem was that we did not delete explain information
when Galera must replay a query.

Could not find easily repeatable test case that would not
cause other problems.

Cherry-pick this fix from the upstream:
commit 6ddedd8f1e0ddcbc24e8f9a005636c5463799ab7
Author: Sergei Petrunia <psergey@askmonty.org>
Date:   Tue Apr 10 11:43:01 2018 -0700

    [mysql-5.6][PR] Issue #802: MyRocks: Statement rollback doesnt work correctly for nes…

    Summary:
    …ted statements

    Variant #1: When the statement fails, we should roll back to the latest
    savepoint taken at the top level.
    Closes https://github.com/facebook/mysql-5.6/pull/804

    Differential Revision: D7509380

    Pulled By: hermanlee

    fbshipit-source-id: 9a6f414

The error occurs because of how the character set and collation are chosen for
stored procedure parameters that have a character data type.  If the character
set and collation are not explicitly stated in the declaration, the server
chooses the database character set and collation in effect at routine creation
time.

To fix the problem, I added explicit character set and collation attributes
for the stored procedure parameters in the install_spider.sql script.

Author:
  Jacob Mathew.

Reviewer:
  Kentoku Shiba.

Cherry-Picked:
  Commit ff0bf451 on bb-10.3-MDEV-15692

MDEV-12632: Source and destination overlap in memcpy, encryption.innodb-discard-import-change fails in buildbot with valgrind

Problem was that if tablespace was encrypted we try to copy
also page 0 from read buffer to write buffer that are in
that case the same memory area.

fil_iterate
	When tablespace is encrypted or compressed its
        first page (i.e. page 0) is not encrypted or
	compressed and there is no need to copy buffer.

Wait until rotation has ended and shutdown before grep to make sure
that dirty pages are on datafiles.

If we use hostnames, it will fail during name resolution on UNIX systems

Also fix perfschema.hostcache_ipv6_max_con.
The test case makes use of a debug switch to execute some special code.
The code does hostname replacement. Every hostname sent during connect
phase becomes santa.claus.ipv4.example.com (or ipv6). This causes a
connection from root@localhost to fail, as root is not registered as
santa claus user. The failure is only apparent on Windows as Unix
systems make use of sockets, which bypass the name resolution check
entirely.

Fix 10.2-specific bug - copy-back is not prepared to handle system
tablespaces with absolute path.

The implementations of the convert_to_basic_const_item() virtual
function for the Item_cache classes should call cache_value() when
value_cached == NULL.

There was a missing argument to service_manager_extend_timeout call
and the signness of arguments did not match.

Wait drop table to be replicated before continuing.

The code in Type_handler_blob****::make_conversion_table_field()
erroneously assumed that row format replication uses
MYSQL_TYPE_TINYBLOB, MYSQL_TYPE_BLOB, MYSQL_TYPE_MEDIUMBLOB,
MYSQL_TYPE_LONGBLOB type codes to tranfer BLOB variations.

In fact, all BLOB variations use MYSQL_TYPE_BLOB as the type
code, while the BLOB packlength (1,2,3 or 4) it tranferred
in metadata.

The bug was introduced by  aee06808
(MDEV-9238 Wrap create_virtual_tmp_table() into a class, split into different steps)

If innodb_fast_shutdown<2, all transactions of active connections
will be rolled back on shutdown. This can take a long time, and
the systemd shutdown timeout should be extended during the wait.

logs_empty_and_mark_files_at_shutdown(): Extend the timeout when
waiting for other threads to complete.

This reverts commit 76ec37f5.

This behaviour change will be done separately in:
MDEV-15832 With innodb_fast_shutdown=3, skip the rollback
of connected transactions

Table_open_cache gets adjusted on server startup to prevent an out of
file descriptor error. However this means that when we reset its value
to default, it does not get re-adjusted. This leads to the mtr
consistency check to fail with different server status at the end of the
test case as opposed to when it started.

To fix the problem, do not make use of the DEFAULT keyword to set the
variable back, instead save the value before any modifications and
restore it from there.

Disable occasionally failing test case galera.galera_var_slave_threads.

Wait until create table is replicated before continuing.

Wait until create tables are replicated to the slave before trying
lock table.

In async IO completion code, after reading a page,Innodb can wait for
completion of other bufferpool reads.
This is for example what happens if change-buffering is active.

Innodb on Windows could deadlock, as it did not have dedicated threads
for processing change buffer asynchronous reads.

The fix for that is to have windows now has the same background threads,
including dedicated thread for ibuf, and log AIOs.

The ibuf/read completions are now dispatched to their threads with
PostQueuedCompletionStatus(), the write and log completions are processed
in thread where they arrive.

Disable more occasionally failing test cases.
	galera.galera_lock_table
	galera.galera_gra_log
	galera.MW-44
	galera.lp1376747
	galera.lp1376747-2
	galera.galera_pc_ignore_sb

Make sure DDL's (create tables) are replicated before continuing to
lock table.

Disable occasionally failing test cases
	pxc-421
	query_cache
	galera_parallel_simple

fil_crypt_read_crypt_data(): Do not attempt to read the tablespace
if the file is unaccessible due to a pending DDL operation, such as
renaming the file or DROP TABLE or TRUNCATE TABLE. This is only
reducing the probability of the race condition, not completely
preventing it.

Adjust the fix for MDEV-15472:
In close_cached_tables(), locked_tables_list.reopen_tables(...) call
might be made when a previous call to some function has already returned
error.
In this scenario, the function should return 0, even if reopen_tables(...)
call has succeeded.

When "FLUSH TABLE ... FOR EXPORT" fails, the SQL layer should rollback
the statement. Otherwise we hit an assert when we try to close the
tables while having a non-empty list of statement transaction participants.

MDEV-13549 Fix test galera.galera_wsrep_desync_wsrep_on

The test tends to fail if many parallel instances of it are executed:

```
mysqltest: At line 23: query 'ALTER TABLE t1 ADD PRIMARY KEY (f1)' failed:
1317: Query execution was interrupted
```

The `ALTER` fails because it is BF aborted due to an earlier `INSERT SELECT`
that is being applied:

```
INSERT INTO t1 (f1) SELECT ...

--connection node_2
SET GLOBAL wsrep_desync = TRUE;
SET SESSION wsrep_on = FALSE;

ALTER TABLE t1 ADD PRIMARY KEY (f1);

SET SESSION wsrep_on = TRUE;
SET GLOBAL wsrep_desync = FALSE;
```

And because the `ALTER` is executed with `wsrep_on = OFF`, it does not
run in total order isolation.
To avoid the problem it must be ensured that the `ALTER` only after the
large `INSERT SELECT` is done. To do so it is sufficient to issue
`SELECT COUNT(*) FROM t1;` from `node_2` before turning off wsrep.
The `SELECT` will trigger `wsrep_sync_wait` and proceed only after the
`INSERT SELECT` from node_1 is done.

Problem was that key rotation from encrypted to unecrypted was skipped
when encryption is disabled (i.e. set global innodb-encrypt-tables=OFF).

fil_crypt_needs_rotation
        If encryption is disabled (i.e. innodb-encrypt-tables=off)
	and there is tablespaces using default encryption (e.g.
	system tablespace) that are still encrypted state we need
	to rotate them from encrypted state to unencrypted state.

Fix test case galera_toi_ddl_nonconflicting as we need to wait
until both alter tables are finished on that Galera node.