Percentile class implemented, most of the functions have the same functionalite as the percentile cont class

all the null values while calculating the number of rows in the partition

Setting handler to have the return type as that of the element by which we are ordering the partition

Check for single element in the order_list is added

Finalised the synatax and have started implementing the class for the PERCENTILE_DISC

#cmakedefine in template file might not create a #define in configured
header file.

Status variables added: Table_open_cache_hits, Table_open_cache_misses,
Table_open_cache_overflows, Table_open_cache_active_instances.

This is a 10.3 specific part of MDEV-13049.
It disables automatic sorting for
"SELECT .. FROM INFORMATION_SCHEMA.{SCHEMATA|TABLES}"
and adjusts the affected tests accordingly.

TODO: enable MDEV-13049 optimization for 10.3

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().

        bind_address variable added.

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().