option leaves the database in inconsistent state,

Analysis: Problem was that atomic writes variable had incorrect
type on same places leading to fact that e.g. OFF option was
not regognized. Furthermore, some error check code was missing
from both InnoDB and XtraDB engines. Finally, when table is
created we have already created the .ibd file and if we can't
set atomic writes it stays there.

Fix: Fix atomic writes variable type to ulint as it should be.
Fix: Add proper error code checking on os errors on both InnoDB
and XtraDB
Fix: Remove the .idb file when atomic writes can't be enabled
to a new table.

Removed: innodb_use_lz4 configuration parameter

Added: innodb_compression_algorithm configuration parameter
0 = no compression, 1 = ZLIB, 2 = LZ4, 3 = LZO

Fixed issue with incorrect trim calculations

asserts can be conditionally compiled out.

see MDEV-5981

another post-fix patch for MDEV-5850: MySQL Bug#21317: SHOW CREATE DATABASE does not obey to lower_case_table_names
(for case-insensitive filesystems)

sql/events.cc:
  for "SHOW EVENTS IN db_name"
sql/sp_head.h:
  for "CREATE EVENT", and everything SP-related
sql/sql_acl.cc:
  privilege check for mysql_change_db()
sql/sql_db.cc:
  for metadata locking of db names
sql/sql_parse.cc:
  any_db is a constant, it is not writable
sql/sql_show.cc:
  for SHOW CREATE TRIGGER and other trigger-related statements

MDEV-5971 Asymmetry between CAST(DATE'2001-00-00') to INT and TO CHAR in prepared statements

Consistently set maybe_null flag, even not-NULL temporal literal may become NULL
in the restrictive sql_mode.

fix uninit variable

Fixed that the we don't change CREATE to CREATE OR REPLACE, except if the slave removed an existing table as part of CREATE.
This will help the following replicaition scenario:
MariaDB 10.0 master (statement replication) -> MariaDB 10.0 slave (row based replication) -> MySQL or MariaDB 5.x slave


mysql-test/r/mysqld--help.result:
  Updated help text
mysql-test/suite/rpl/r/create_or_replace_mix.result:
  Added more tests
mysql-test/suite/rpl/r/create_or_replace_row.result:
  Added more tests
mysql-test/suite/rpl/r/create_or_replace_statement.result:
  Added more tests
mysql-test/suite/rpl/t/create_or_replace.inc:
  Added more tests
sql/handler.h:
  Added org_options so that we can detect what come from the query and what was possible added later.
sql/sql_insert.cc:
  Only write CREATE OR REPLACE if was originally specified or if we delete a conflicting table as part of create
sql/sql_parse.cc:
  Remember orginal create options
sql/sql_table.cc:
  Only write CREATE OR REPLACE if was originally specified or if we delete a conflicting table as part of create
sql/sys_vars.cc:
  Updated help text

            TABLE_SHARE::visit_subgraph

tc_acquire_table() is not ready to update TABLE::in_use without mutex:
thr1: table= free_tables.pop_front(); // table->in_use is 0
thr2: tdc_remove_table();
thr2: find_deadlock(); // assert(table->in_use != 0)
thr1: table->in_use= thd;

Protect update of TABLE::in_use by LOCK_table_share.

mysql.column_stats.

- Fix valgrind failure: don't touch table_list->master_had_triggers 
  when RBR_TRIGGERS is not compiled in.

post-fix patch for MDEV-5850: MySQL Bug#21317: SHOW CREATE DATABASE does not obey to lower_case_table_names

- Show a line with "Engine-independent statistics collected" when ANALYZE command
  caused EITS statistics to be recollected.

  to use named pipe on Windows by specifying the host as '.'
  This addresses MDEV-5952.
modified:
  storage/connect/myconn.cpp

- Clean some unused code
modified:
  storage/connect/connect.cc
  storage/connect/connect.h
  storage/connect/ha_connect.cc
  storage/connect/ha_connect.h

- Dont substract unsigned numbers, use correct calculations.
- (there is no testcase because effort is required to come up with it)

- Move [some] engine-agnostic tests from t/selectivity.test to t/selectivity_no_engine.test
- Move Histogram::point_selectivity to sql_statistics.cc

- Histogram::find_bucket() should not walk off the end of the value range.
- Address review feedback in Histogram::point_selectivity(): different handling
  for zero-width buckets, and explanations.

  (Inadequate background LRU flushing for write workloads with InnoDB compression).
    
    If InnoDB compression is used and the workload has writes, the
    following situation is possible. The LRU flusher issues an LRU flush
    request for an instance.  buf_do_LRU_batch decides to perform
    unzip_LRU eviction and this eviction might fully satisfy the
    request. Then buf_flush_LRU_tail checks the number of flushed pages in
    the last iteration, finds it to be zero, and wrongly decides not to
    flush that instance anymore.
    
    Fixed by maintaining unzip_LRU eviction counter in struct
    flush_counter_t variables, and checking it in buf_flush_LRU_tail when
    deciding whether to stop flushing the current instance.

    Fix provided by: Laurynas Biveinis (Percona)
 
Added test cases for new configuration files to get mysql-test-run suite sys_vars
to pass. Fix some small errors.

(Inadequate background LRU flushing for write workloads with InnoDB compression).
  
  If InnoDB compression is used and the workload has writes, the
  following situation is possible. The LRU flusher issues an LRU flush
  request for an instance.  buf_do_LRU_batch decides to perform
  unzip_LRU eviction and this eviction might fully satisfy the
  request. Then buf_flush_LRU_tail checks the number of flushed pages in
  the last iteration, finds it to be zero, and wrongly decides not to
  flush that instance anymore.
  
  Fixed by maintaining unzip_LRU eviction counter in struct
  flush_counter_t variables, and checking it in buf_flush_LRU_tail when
  deciding whether to stop flushing the current instance.

Added test cases for new configuration files to get mysql-test-run suite sys_vars
to pass. Fix some small errors.

remove dead code

MDEV-5839 TokuDB tables not properly cleaned on DROP DATABASE

TokuDB does not support discover_table_names() and writes no files
in the database directory, so automatic filename-based
discover_table_names() doesn't work either. So, it must force .frm
file to disk in ::create()

Don't abort plugin reads whem mpvio->make_it_fail is set - this can leak information.