ColumnMask is enabled before aggregation, rather than after aggregation.

[jywjyw]

When using ColumnMask, I encounter an issue where ColumnMask is enabled before aggregation, rather than after aggregation.
For example, I have this table about person:

name 
------
Jim
Bob

Then implement columnMask:

public class MySysAcl implements SystemAccessControl {
    public Optional<ViewExpression> getColumnMask(SystemSecurityContext context, CatalogSchemaTableName cst, String columnName, Type type)    {
		return Optional.of(ViewExpression.builder()
				.identity("root")
				.catalog(cst.getCatalogName())   					
				.schema(cst.getSchemaTableName().getSchemaName())	
				.expression("'***'")
				.build());
    	}
    }
}

When execute "SELECT * FROM T", looks fine:

name
-----
***
***

But when execute "SELECT COUNT(DISTINCT NAME) FROM T", I got:

count
-----
1

I believe it should return 2, as ColumnMask should take effect during display rather than during computation.

Somebody has submitted similar issue: #17696.

If I want to perform column masking only when displaying query results, can I do it by implementing connector? Thanks very much!

[findepi]

This is working as designed.
closing in favor of #17696. let's continue discussion there