BUG#26447 prefer a clustered key for an index scan, as secondary index is always slower
  ... which was fixed to cause
BUG#35850 queries take 50% longer
  ... and was reverted

and

BUG#39653 prefer a secondary index for an index scan, as clustered key is always slower
  ... which was fixed to cause
BUG#55656 mysqldump takes six days instead of half an hour
  ... and was amended with a special case workaround


sql/opt_range.cc:
  move get_index_only_read_time() into the handler class
sql/sql_select.cc:
  use cost not an index length when choosing a cheaper index

and mistakingly pulled in back for maria-5.1.50.

Fixes for bugs found by running test case for LP#608369 "Page: 1 Found wrong page type 0' on CHECK TABLE EXTENDED"
Fixed overflow when using long --debug=xxxxxx line.
Fixed that "mysqld --disable-debug --debug" works.
Ensure that MariaDB doesn't start if the Aria engine didn't start and we are using Aria for temporary tables.
More DBUG_ASSERT() and more info in debug log.


dbug/dbug.c:
  Fixed crash in mysqld caused by an overflow when using long --debug=xxxxxx line
sql/mysqld.cc:
  Fixed that "mysqld --disable-debug --debug" works.
  Documented myisam-recover=OFF option
storage/maria/ha_maria.cc:
  Ensure that MariaDB doesn't start if the Aria engine didn't start and we are using Aria for temporary tables.
storage/maria/ma_delete.c:
  Added missing write of changed key on node page.
  This could fix LP#608369 "Page: 1 Found wrong page type 0' on CHECK TABLE EXTENDED"
  Changed so that we log page numbers (not positions)
  Added KEY_OP_DEBUG_2 log entry to get more debug information into the log
storage/maria/ma_key_recover.c:
  Changed so that we log page numbers (not positions)
  In case of wrong page information after index_redo, dump pages to debug log
storage/maria/ma_loghandler.h:
  Added KEY_OP_DEBUG_2
storage/maria/ma_search.c:
  Changed so that we log page numbers (not positions)
storage/maria/ma_write.c:
  Changed so that we log page numbers (not positions)

sql/sql_parse.cc:
  Make some not commonly used functions with big local variables to separate functions to make default stack usage smaller.
  Decrease size of db_buff[] (Was bigger than needed)
  Allocate current_global_status_var with malloc().
storage/maria/ha_maria.cc:
  Don't allocate HA_CHECK on stack (it's > 100K)
storage/maria/ma_check.c:
  Removed duplicated code

- _ma_apply_redo_index: Assertion `page_offset != 0 && page_offset + length <= page_length' failed
Fixes one bug and one log assert when inserting rows:
- _ma_log_split: Assertion `org_length <= info->s->max_index_block_size' failed
- write_block_record:  Assertion '(data_length < MAX_TAIL_SIZE(block_size)' failed
Mark in recovery log where _ma_log_add() calls was done (for better debugging).

storage/maria/ma_bitmap.c:
  Don't write a head part on a tail page. (Caused an assert in write_block_record())
storage/maria/ma_delete.c:
  Mark in recovery log where _ma_log_add() calls was done
storage/maria/ma_key_recover.c:
  Mark in recovery log where _ma_log_add() calls was done
  Fixed not handled logging case for overfull index pages.
storage/maria/ma_key_recover.h:
  Mark in recovery log where _ma_log_add() calls was done
storage/maria/ma_loghandler.h:
  Mark in recovery log where _ma_log_add() calls was done
storage/maria/ma_rt_key.c:
  Mark in recovery log where _ma_log_add() calls was done
storage/maria/ma_write.c:
  Mark in recovery log where _ma_log_add() calls was done.
  Fixed wrong call to _ma_split_page() for overfull pages

The reason for this was that some bitmap test functions changed the bitmap, which caused problems when the same bitmap was used by multiple threads.


include/my_bitmap.h:
  Changed order of elements to get better alignment.
mysys/my_bitmap.c:
  Change bitmap test functions to not modify the bitmap.
  Fixed compiler errors in test_bitmap

Updated results for failing test cases (In all cases the estimated number of rows was different)

The condition over the outer tables now are extracted from
the on condition of any outer join. This condition is
saved in a special field of the JOIN_TAB structure for
the first inner table of the outer join. The condition
is checked before the first inner table is accessed. If 
it turns out to be false the table is not accessed at all
and a null complemented row is generated immediately.

the setting of optimizer switch for table elimination.

The implementation of the virtual method not_null_tables for the class
Item_outer_ref must always return 0.

Made sure that rr_quick is used to read the next record whenever
a quick select is used to retrieve the table records.

Fixed crashing bug when doing ALTER TABLE RENAME with transactional tables.

client/mysqltest.cc:
  Added errno to error message for system calls (delete, rename etc)
  Write error message for failures of system calls
mysql-test/include/cleanup_fake_relay_log.inc:
  Disable warnings for remove_file
mysql-test/include/diff_tables.inc:
  Disable warnings for remove_file
mysql-test/include/maria_empty_logs.inc:
  Disable warnings for remove_file
mysql-test/include/maria_make_snapshot.inc:
  Disable warnings for remove_file
mysql-test/include/maria_make_snapshot_for_feeding_recovery.inc:
  Disable warnings for remove_file
mysql-test/include/mysqlhotcopy.inc:
  Disable warnings for remove_file
mysql-test/include/ndb_backup.inc:
  Disable warnings for remove_file
mysql-test/include/ndb_backup_print.inc:
  Disable warnings for remove_file
mysql-test/r/alter_table_trans.result:
  Test of crashing ALTER TABLE RENAME bug
mysql-test/t/alter_table_trans.test:
  Test of crashing ALTER TABLE RENAME bug
mysql-test/t/mysqltest.test:
  Disable warnings for remove_file and move_file
mysys/my_copy.c:
  Fixed wrong error message
sql/sql_table.cc:
  Fixed crashing bug when doing ALTER TABLE RENAME with transactional tables.

libtool does not like it and fails the build.