where is the performance hit with null values in indexes?

MySQL & MariaDB Other MySQL® Questions
1

Hi

Where is the performance hit with having NULL values in indexes. On the creation of the record index, on retrieval, or both ?

Cheers

Billy.

2

I can’t think of a case where there would be a problem on insert. For retrieval, it depends on the query. Have you read High Performance MySQL Second Edition? We talked about it at length there.