Updated --help text to declare --slave-parallel-threads as an alpha feature

mysql-test/r/mysqld--help.result:
  Updated --help text
sql/slave.cc:
  Added missing trans_retries++ that caused rpl_deadlock_innodb.test to fail.
  This is safe as this part is never run in parallel.
sql/sql_base.cc:
  Fixed temporary table handling (part of merge)
sql/sys_vars.cc:
  Updated --help text to declare --slave-parallel-threads as an alpha feature

The merge is still missing a few hunks related to temporary tables and
InnoDB log file size. The associated code did not seem to exist in
10.0, so the merge of that needs more work. Until this is fixed, there
are a number of test failures as a result.

In parallel replication, there are two kinds of events which are
executed in different ways.

Normal events that are part of event groups/transactions are executed
asynchroneously by being queued for a worker thread.

Other events like format description and rotate and such are executed
directly in the driver SQL thread.

If the direct execution of the other events were to update the old-style
position, then the position gets updated too far ahead, before the normal
events that have been queued for a worker thread have been executed. So
this patch adds some special cases to prevent such position updates ahead
of time, and instead queues dummy events for the worker threads, so that
they will at an appropriate time do the position updates instead.

(Also fix a race in a test case that happened to trigger while running
tests for this patch).

which makes it possible to add more world language collations
with very complex collation rules (e.g. Myanmar):
- Weight string for a single character in a user defined collation
  was erroneously limited to 7 weights (instead of 8 weights).
  Added an extra element in the user-defined weight arrays,
  to fit 8 non-zero weights.
- Weight string limit for contractions was made two times longer (16 weights),
  which allows longer contractions without affecting the performance
  of filesort.
- A user-defined collation now refuses to initialize and reports an error
  in case if a weight string gets longer than 8 weights for a single character,
  or longer than 16 weights for a contraction. Previously weight strings
  for such characters (and contractions) were cut, so a collation
  could silently start with wrong rules.
- Fixed a bug in handling rules like "&a << b" in combination with
  shift-after-method="expand". The primary weight for "b" was not
  correctly calculated, which erroneously made "b" primary greater than "a"
  instead of primary equal to "a".

MDEV-4736 - Assertion `! is_set()' fails in Diagnostics_area::set_ok_status on
            UPDATE which violates constraint on a remote table

MDEV-5196: Server hangs or assertion `!thd->wait_for_commit_ptr' fails on MASTER_POS_WAIT with slave-parallel-threads > 0

Fix a couple of issues in MDEV-4506, Parallel replication:

 - Missing mysql_cond_signal(), which could cause hangs.

 - Fix incorrect update of old-style replication position.

 - Change assertion to error handling (can trigger on manipulated/
   corrupt binlog).

  
  There was 2 problems:
  1) coping/moving of the same type (usually casting) as sizeof() (solved in different ways depends on the cause);
  2) using 'const' in SSL_CTX::getVerifyCallback() which return object (not reference) and so copy of the object will be created and 'const' has no sens.

In parallel replication, when the IO thread switches relay log,
the SQL thread re-opens the current relaylog and seeks to the
current position. There was a race that would cause it to
sometimes seek to the wrong position, causing corruption and
crash.

Analysis:
st_select_lex_unit::prepare() computes can_skip_order_by as TRUE.
As a result join->prepare() gets called with order == NULL, and
doesn't do name resolution for the inner ORDER clause. Due to this
the prepare phase doesn't detect that the query references non-exiting
function and field.
  
Later join->optimize() calls update_used_tables() for a non-resolved
Item_field, which understandably has no Field object. This call results
in a crash.

Solution:
Resolve unnecessary ORDER BY clauses to detect if they reference non-exising
objects. Then remove such clauses from the JOIN object.

MDEV-5189: Error handling in parallel replication.

Fix error handling in parallel worker threads when a query fails:

 - Report the error to the error log.

 - Return the error back, and set rli->abort_slave.

 - Stop executing more events after the error.

  GRANT ... IDENTIFIED BY [ PASSWORD ] ...
  GRANT ... IDENTIFIED VIA ... [ USING ... ]
  GRANT ... REQUIRE ...
  GRANT ... MAX_xxx ...
  SET PASSWORD FOR ... = ...

modified:
  storage/connect/ha_connect.cc
  storage/connect/odbconn.cpp
  storage/connect/odbconn.h

  Fix option other ignored when parsing URL

modified:
  storage/connect/ha_connect.cc
  storage/connect/mysql-test/connect/t/mysql.test
  storage/connect/mysql-test/connect/t/mysql_grant.test
  storage/connect/tabmysql.cpp
  storage/connect/tabmysql.h

modified:
  storage/connect/ha_connect.cc
  storage/connect/myconn.h
  storage/connect/tabmysql.cpp
  storage/connect/tabmysql.h

  Srcdef definition
  Execute command tables
  uncomplete connect string

modified:
  storage/connect/ha_connect.cc
  storage/connect/odbccat.h
  storage/connect/odbconn.cpp
  storage/connect/odbconn.h
  storage/connect/plgdbsem.h
  storage/connect/plgdbutl.cpp
  storage/connect/tabodbc.cpp

Two problems were fixed:

1. When not in GTID mode (master_use_gtid=no), then we must not apply events
   in different domains in parallel (in non-GTID mode we are not capable of
   restarting at different points in different domains).

2. When transactions B and C group commit together, but after and separate
   from A, we can apply B and C in parallel, but both B and C must not start
   until A has committed. Fix sub_id to be globally increasing (not just
   per-domain increasing) so that this wait (which is based on sub_id) can be
   done correctly.

Merge from MySQL-5.6

(a bug in upstream)

Do not update relay-log.info and master.info on disk after every event
when using GTID mode:

 - relay-log.info and master.info are not crash-safe, and are not used
   when slave restarts in GTID mode (slave connects with GTID position
   instead and immediately rewrites the file with the new, correct
   information found).

 - When using GTID and parallel replication, the position in
   relay-log.info is misleading at best and simply wrong at worst.

 - When using parallel replication, the fact that every single
   transaction needs to do a write() syscall to the same file is
   likely to become a serious bottleneck.

The files are still written at normal slave stop.

In non-GTID mode, the files are written as normal (this is needed to
be able to restart after slave crash, even if such restart is then not
crash-safe, no change).

Fix uninitialised variable.

Implement --slave-parallel-max-queue to limit memory usage
of SQL thread read-ahead in the relay log.

- Backport MySQL's fix: do set ha_partition::m_pkey_is_clustered for ha_partition 
  objects created with handler->clone() call.
- Also, include a testcase.

MDEV-5176 Server crashes in fill_schema_applicable_roles on select from APPLICABLE_ROLES after a suicide

Don't assume that thd->security_ctx->priv_user is an actually existing user account

MDEV-5170 Assertion `(&(&acl_cache->lock)->m_mutex)->count > 0 && pthread_equal(pthread_self(), (&(&acl_cache->lock)->m_mutex)->thread)' fails after restarting server with a pre-created role grants

lock acl_cache->lock mutex for the duration of acl_load

Fix some more parts of old-style position updates.
Now we save in rgi some coordinates for master log and relay log, so
that in do_update_pos() we can use the right set of coordinates with
the right events.

The Rotate_log_event::do_update_pos() is fixed in the parallel case
to not directly update relay-log.info (as Rotate event runs directly
in the driver SQL thread, ahead of actual event execution). Instead,
group_master_log_file is updated as part of do_update_pos() in each
event execution.

In the parallel case, position updates happen in parallel without
any ordering, but taking care that position is not updated backwards.
Since position update happens only after event execution this leads
to the right result.

Also fix an access-after-free introduced in an earlier commit.

test time increased to be working on all timezones.

MDEV-5172 safe_mutex: Trying to lock mutex when the mutex was already locked on using a role and I_S role tables

don't forget to unlock if the current role isn't found