Merged https://github.com/facebook/mysql-5.6/commit/615dd07d900ce08948340b6c11e37fd1d2a91065 from https://github.com/facebook/mysql-5.6/
authored by rongrong. Removed C++11 requirement by using
std::map instead of std::unordered_set.

Add analysis to leaf pages to estimate how fragmented an index is
and how much benefit we can get out of defragmentation.

Conflicts:
	sql/log.cc
	sql/rpl_rli.cc
	sql/sql_repl.cc

MDEV-6403: Temporary tables lost at STOP SLAVE in GTID mode if master has not rotated binlog since restart

The binlog contains specially marked format description events to mark
when a master restart happened (which could have caused temporary
tables to be silently dropped). Such events also cause slave to close
temporary tables.

However, there was a bug that if after this, slave re-connects to the
master in GTID mode, the master can send an old format description
event again. If temporary tables are closed when such event is seen
for the second time, it might drop temporary tables created after that
event, and cause replication failure.

With this patch, the restart flag of the format description event is
cleared by the master when it is sent to the slave in a subsequent
connection, to avoid the errorneous temp table close.

MDEV-6589: Incorrect relay log start position when restarting SQL thread after error in parallel replication

The problem occurs in parallel replication in GTID mode, when we are using
multiple replication domains. In this case, if the SQL thread stops, the
slave GTID position may refer to a different point in the relay log for each
domain.

The bug was that when the SQL thread was stopped and restarted (but the IO
thread was kept running), the SQL thread would resume applying the relay log
from the point of the most advanced replication domain, silently skipping all
earlier events within other domains. This caused replication corruption.

This patch solves the problem by storing, when the SQL thread stops with
multiple parallel replication domains active, the current GTID
position. Additionally, the current position in the relay logs is moved back
to a point known to be earlier than the current position of any replication
domain. Then when the SQL thread restarts from the earlier position, GTIDs
encountered are compared against the stored GTID position. Any GTID that was
already applied before the stop is skipped to avoid duplicate apply.

This patch should have no effect if multi-domain GTID parallel replication is
not used. Similarly, if both SQL and IO thread are stopped and restarted, the
patch has no effect, as in this case the existing relay logs are removed and
re-fetched from the master at the current global @@gtid_slave_pos.

Replaced hash with lock-free hash.

Extended lf-hash implementation to accept user defined hash function.

Added initializer callback to lf-hash. Needed to initialize properly non-POD
types.

Simplified MDL_object_lock and MDL_scoped_lock dichotomy so that they can be
stored in LF_HASH. This was done by moving out their differences to a
MDL_lock_strategy structure which is referenced from the MDL_lock object by
pointer.

Replaced m_ref_usage, m_ref_release, m_is_destroyed and m_version with single
m_state, which is updated atomically. Needed to get rid of MDL_map::m_mutex.

Removed MDL map partitions. Won't be needed when this MDEV is implemented.

Removed MDL objects cache. Won't be needed when this MDEV is implemented.

Based on the patch by Sriram Patil, made under terms of GSoC 2014.

of very similar copies of my_well_formed_len_xxx(), implemented
for big5, cp932, euckr, eucjpms, gb2312m gbk, sjis, ujis.

adjust suppression rules after warning message format change

Adding a new virtual function MY_CHARSET_HANDLER::copy_abort().
Moving character set specific code into the correspoding implementations
(for simple, multi-byte and mbmaxlen>1 character sets).

error messages.

* remove useless suppressions from the test file, when a plugin doesn't
  load, the file isn't executed anyway
* add the suppression to mysql-test-run.pl instead

Take into account that PIE binaries are loaded at some offset, so
addresses cannot be directly resolved with addr2line. Find this
offset and subtract it before resolving an address.

MDEV-7000 Assertion `0' failed in Protocol::end_statement() on executing DDL under innodb_fake_changes=1

correct the if() condition to match the behavior of the old code
that this if() was supposed to replace

There were two issues:

* set_var_default_role::user was overwritten with a new value,
  allocated in the thd->mem_root, which is reset between executions.
  That was causing the crash. Solved by introducing set_var_default_role::real_user

* when privilege tables were opened on EXECUTE, the reprepare_observer
  would abort the statement (as privilege tables are opened using
  the local TABLE_LIST that doesn't preserve metadata from PREPARE, so
  reprepare_observer thought they're changed). This issue also applied
  to SET PASSWORD. Solved by disabling reprepare_observer.

Added logic to sort gtid list based on domain_id before
populating them in string. Added a test case.

Removed 'galera-sst-mode' option from mysqldump and added logic
in wsrep_sst_mysqldump script to retrieve gtid_binlog_state from
donor node and send it to the joiner node.

Added an include file to check galera library version.

* Changed loopback detection to be done via ifa->ifa_flags
* Removed unused function wsrep_guess_address()

by adding a new class String_copier.

This is a pre-requisite patch for MDEV-6566 and MDEV-6572,
to avoid adding more similar code.

Create_tmp_table was called incorrectly called in
select_materialized_with_stats::create_result_table, having keep_row_order
passed for the do_not_open parameter and keep_row_order always set to false.

file_key_management_plugin is used

Fixed error handling and added disabling InnoDB redo log encryption
if encryption key management plugin is not there.

- Remove the compiler warning, add assert statements.
- make select_describe() not call mysql_explain_union() for
  views that were "merged for INSERT".

file_key_management_plugin is used

Fixed error handling and added disabling InnoDB redo log encryption
if encryption key management plugin is not there.

of encryption/compression pages and that will happen if and only
if dirty pages are written to the disk.