I have a table with 250K rows in my test database. (There are a few hundred millions in production, we can observe the same issue there.) The table has an nvarchar2(50) string identifier, not null, ...
Given a table with columns A, B, and C of type CHAR(15) and an unique index If I have a query with a WHERE clause specifying A and C, oracle's optimizer chooses to do an index range scan. But if I ...