I'd say that suggesting there's a "penalty" at all implies a naive hardware setup[1]. Total system I/O is a finite resource, but this can be hard to reach if i

I'd say that suggesting there's a "penalty" at all implies a naive hardware setup[1]. Total system I/O is a finite resource, but this can be hard to reach if indexes are on separate spindles[2] from the data and each other. This can cost substantially more initially, but disappears at scale. Perhaps, then, as for the OP's original topic, one mistake is not hiring someone who knows these performance strategies. Another is using an RDBMS that doesn't support them. [1] which, granted, is far and away the norm [2] or sets of spindles, or SSDs