- The valgrind warning came from JOIN::optimize() (sql_select.cc:1123)

- Allocate only enough memory that we need for key status
  - Saves ~100K temp usage on maria_open

The background is that one user had a lot of views and using some complex
queries on information schema temporary memory of more than 2G was used.

- Added new element 'total_alloc' to MEM_ROOT for easier debugging.
- Added MAX_MEMORY_USED to information_schema.processlist.
- Added new status variable "Memory_used_initial" that shows how much MariaDB
  uses at startup. This gives the base value for "Memory_used".
- Reuse memory continuously for information schema queries instead of
  only freeing memory at query end.

Other things
- Removed some not needed set_notnull() calls for not null columns.

- Expand paths also for jemalloc
- Test also if tcmalloc or jemalloc is in /usr/lib64
- Take into account that .so has a version
- Remove automatic adding of flavors ( _minial, _debug). Better to
  have user specify these directly
- Changed documentation link to MariaDB
- Don't give extra error if mysqld_safe_helper doesn't exist

Also don't abort if global_status_var.global_memory_used != 0 on not
normal exit as then it's likely that not all memory is released.

MDEV-13568: Purge is not blocked by LOCK TABLES. Should it?

MDEV-13893/MDEV-12699: Crash recovery of corrupted or non-decryptable
pages is broken.

Signed-off-by: Daniel Black <daniel@linux.vnet.ibm.com>

When MariaDB 10.1.0 introduced table options for encryption and
compression, it unnecessarily changed
ha_innobase::check_if_supported_inplace_alter() so that ALGORITHM=COPY
is forced when these parameters differ.

A better solution is to move the check to innobase_need_rebuild().
In that way, the ALGORITHM=INPLACE interface (yes, the syntax is
very misleading) can be used for rebuilding the table much more
efficiently, with merge sort, with no undo logging, and allowing
concurrent DML operations.

If InnoDB or XtraDB recovered committed transactions at server
startup, but the processing of recovered transactions was
prevented by innodb_read_only or by innodb_force_recovery,
an assertion would fail at shutdown.

This bug was originally reproduced when Mariabackup executed
InnoDB shutdown after preparing (applying redo log into) a backup.

trx_free_prepared(): Allow TRX_STATE_COMMITTED_IN_MEMORY.

trx_undo_free_prepared(): Allow any undo log state. For transactions
that were resurrected in TRX_STATE_COMMITTED_IN_MEMORY
the undo log state would have been reset by trx_undo_set_state_at_finish().

MDEV-13997 Change Item_bool_rowready_func2 to cache const items at fix time rather than evaluation time

Side effect: the second debug Note in cache_temporal_4265.result disappeared.

Before this change:
- During JOIN::cache_const_exprs(),
  Item::get_cache() for Item_date_add_interval() was called.
  The data type for date_add('2001-01-01',interval 5 day) is VARCHAR,
  because the first argument is VARCHAR (not temporal).
  Item_get_cache() created Item_cache_str('2001-01-06').
- During evaluate_join_record(), get_datetime_value() was called,
  which called Item::get_date() for Item_cache_str('2001-01-06').
  This gave the second Note. Then, get_datetime_value() created
  a new cache, now Item_cache_temporal for '2001-01-06', so not
  further str_to_datetime() happened.

After this change:
- During tem_bool_rowready_func2::fix_length_and_dec(),
  Arg_comparator::set_cmp_func_datetime() is called,
  which immediately creates an instance of Item_cache_date for
  the result of date_add('2001-01-01',interval 5 day).
  So later no str_to_datetime happens any more,
  neither during JOIN::cache_const_exprs(),
  nor during evaluate_join_record().

Forgot to put the updated rocksdb.result in

Downscale rocksdb.add_index_inplace_sstfilewriter to be 10x smaller

Fix a race condition in the testcase.

ReadFile/WriteFile operations.

Innodb opens files with FILE_FLAG_OVERLAPPED. lpNumberOfBytesRead/Written
are documented to be potentially inaccurate in this case,
(possibly even if async operations complete synchronously?)

The fix is to always pass NULL for the correspondng parameters,
as recommended by  MSDN. Read the actual counts with
GetQueuedCompletionStatus() or GetOverlappedResult().

os_file_get_size(): Use fstat() instead of calling lseek() 3 times.
In this way, concurrent calls to this function should not interfere
with each other.

Suggested by Vladislav Vaintroub.

The predicate page_is_root() would not hold if btr_create() fails
before the root page is fully initialized. Move the debug assertion
from btr_free_root_invalidate() to its other caller,
btr_free_if_exists(). In that caller, we actually already checked
for page_is_root().

os_file_set_size(): Sometimes the file already is large enough.
Avoid calling posix_fallocate() with a non-positive argument.
Also, add a missing space to an error message.

Adjust and enable rocksdb.2pc_group_commit test

With this patch, parameters passed to posix_fallocate() will be
the same as they were prior to refactoring in  commit b731a5bc

In particular, 'offset' parameter for posix_fallocate is again current_file_size
and 'length' is new_file_size - current_file_size.

This seems to fix crashes on ancient Linux (kernel 2.6).

The assertion failure was relaxed in
commit 02ba15a9
but it was not enough, because another assertion would fail.

trx_undo_free_prepared(): Allow any undo log state. For transactions
that were resurrected in TRX_STATE_COMMITTED_IN_MEMORY
the undo log state would have been reset by trx_undo_set_state_at_finish().

The redo log record MLOG_UNDO_HDR_DISCARD is never written, and
the function trx_undo_discard_latest_update_undo() is never called
outside crash recovery.

Starting with MariaDB 10.2.2, crash recovery from an older InnoDB
version is refused. Therefore, we can safely remove the code for
parsing this long-unused redo log record type.

The use of MLOG_UNDO_HDR_DISCARD was removed by Heikki Tuuri,
the original designer and author of InnoDB, more than 13 years ago:

  commit 3caab0f3
  Author: unknown <heikki@hundin.mysql.fi>
  Date:   Thu Mar 18 14:57:22 2004 +0200

    trx0undo.h, trx0undo.c, trx0trx.c:
      Update an obsolete comment about trx commit: we can no longer call
      trx_undo_update_cleanup_by_discard(), and actually, the idea to
      call it was erroneous, it cannot work