What are two ways in which normalizing your tables helps improve performance In MySQL?
A.
Smaller table sizes and row lengths improve sorting operations.
B.
Separate tables allow indexing more columns.
C.
Fewer nullable column improve index usage.
D.
Normalizing Improves the performance of innodb_file_per _table.
A. and C.
Are you sure about the answer? The website says just D. Is D incorrect?
C looks good.
https://dev.mysql.com/doc/refman/5.5/en/data-size.html
Avoid NULL if possible.
A lot of tables include nullable columns even when the application does not need to store NULL (the absence of a value), merely because it’s the default. It’s usually best to specify columns as NOT NULL unless you intend to store NULL in them.
It’s harder for MySQL to optimize queries that refer to nullable columns, because they make indexes, index statistics, and value comparisons more complicated. A nullable column uses more storage space and requires special processing inside MySQL. When a nullable column is indexed, it requires an extra byte per entry and can even cause a fixed-size index (such as an index on a single integer column) to be converted to a variable-sized one in MyISAM.
The performance improvement from changing NULL columns to NOT NULL is usually small, so don’t make it a priority to find and change them on an existing schema unless you know they are causing problems. However, if you’re planning to index columns, avoid making them nullable if possible.
B C
I agree with B and C
Usually posts some very fascinating stuff like this. If you are new to this site.
A, C