the system variable @@in_subquery_conversion_threshold

Adding missing commands into sql_yacc_ora.yy:

%token  VALUES_IN_SYM
%token  VALUES_LESS_SYM

and their parser hacks with Select->parsing_place.

Note: the grammar for table_value_constructor will be merged later separately.

Ideally, we would move some code from
ha_innobase::prepare_inplace_alter_table() to
ha_innobase::check_if_supported_inplace_alter(),
but the API does not really allow us to return errors; it can
only inform which forms of ALGORITHM and LOCK are allowed.

So, we have to duplicate some logic between the "check" and "prepare"
phases. We do the duplication by calling common functions.

instant_alter_column_possible(): Check if instant column operation
is possible. Invoked from both
ha_innobase::check_if_supported_inplace_alter() and
prepare_inplace_alter_table_dict().

ha_innobase::check_if_supported_inplace_alter(): Before refusing
certain operations if FULLTEXT INDEX exist, check if instant ALTER TABLE
is possible and return early if it is the case.

prepare_inplace_alter_table_dict(): Before checking the limitations
on FULLTEXT INDEX, check if instant ALTER TABLE is possible, and suppress
the checks if it is the case. If instant ADD COLUMN is used when the
table already contains FULLTEXT INDEX, do account for a
hidden FTS_DOC_ID_INDEX in a debug assertion.

finish_resize_simple_key_cache removed argument acquire for acquiring
locks.

resize_simple_key_cache enforces assertion that the cache is inited.

read_block was really two functions, primary and secondary so separated
as such. Make the callers of read_block explictly use the required function.
Signed-off-by: Daniel Black <daniel@linux.vnet.ibm.com>

- Also added missing copyright notices

As a result of this merge the code for the following tasks appears in 10.3:
- MDEV-12172 Implement tables specified by table value constructors
- MDEV-12176 Transform [NOT] IN predicate with long list of values INTO
             [NOT] IN subquery.

Added the median function to the parser , it should behave as a percentile_cont function with its argument fixed to 0.5

Added fix_fields for percentile function to check the type of argument and to ensure that only numeric arguments are allowed

Additionally, allow a query with window functions to be killed by the user during
its execution.

Fixed indentation in the syntax rules for the sql_yacc.yy , also added the rules of the percentile functions to
the sql_yacc_ora.yy

made changes according to the review, mostly removing unused code and fixing code to follow the  coding conventions

  1)ER_ARGUMENT_OUT_OF_RANGE: This error is thrown if the argument of the percentile function is not in the range [0,1]
  2)ER_ARGUMENT_NOT_CONSTANT: This error is thrown if the argument of the percnetile function is not constant in the
    entire partition of the window function

Added the error ER_WRONG_TYPE_FOR_PERCENTILE_CONT, which ensures that the result type for percentile_cont is always numerical

Added the error ER_NOT_SINGLE_ELEMENT_ORDER_LIST for th percentile functions, these ensure that for the percentile
function we have the order list with exactly one element

Added the function setting_handler_for_percentile_function() for the percentile_disc function that would
set the type of the result field for percentile_disc. Percentile_cont would habe double precision result type

if we get any error during the add function call. This is currently used only for the
percentile functions

  -ER_NOT_SINGLE_ELEMENT_ORDER_LIST
  -ER_WRONG_TYPE_FOR_PERCENTILE_CONT
  -ER_ARGUMENT_NOT_CONSTANT
  -ER_ARGUMENT_OUT_OF_RANGE

Val_str function added for the percentile_disc function, as it can have result type as STRING_RESULT

Ensured that the the element in the order by clause should have a numerical time, if not throw an error

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