v.21.12Improvements

Fix LowCardinality of Int256 Creation Issue

Fix the issue that LowCardinality of Int256 cannot be created. #31832 (alexey-milovidov).
Fixed an issue preventing the creation of LowCardinality type columns based on the Int256 data type.

Why it matters

This fix resolves the problem where users could not create columns of type LowCardinality(Int256). It enables efficient storage and processing for high-precision 256-bit integers with low cardinality optimization, improving performance and reducing memory usage for applicable datasets.

How to use it

Users can now define table columns or cast expressions using LowCardinality(Int256) normally, for example:
CREATE TABLE example (
id Int64,
value LowCardinality(Int256)
) ENGINE = MergeTree() ORDER BY id;