This patch improves handling of NULLs in textual fields in ColumnStore.
Previously empty strings were considered NULLs and it could be a problem
if data scheme allows for empty strings. It was also one of major
reasons of behavior difference between ColumnStore and other engines in
MariaDB family.
Also, this patch fixes some other bugs and incorrect behavior, for
example, incorrect comparison for "column <= ''" which evaluates to
constant True for all purposes before this patch.
* MCOL-5092 Ensure column width is correct for datatype
Change MODA return type to STRING
Modify MODA to handle every numeric type
* MCOL-5162 MODA to support char and varchar with collation support
Fixes to the aggregate bit functions
When we fixed the storage sign issue for MCOL-5092, it uncovered a problem in the bit aggregates (bit_and, bit_or and bit_xor). These aggregates should always return UBIGINT, but they relied on the type of the argument column, which gave bad results.
WF::percentile runtime threw an exception b/c of wrong DT deduced from its argument
Replaced literals with constants
Tought WF_sum_avg::checkSumLimit to use refs instead of values
