Subject RE: [Firebird-Architect] Clustered indexes
Author Claudio Valderrama C.
> From: Jim Starkey
> If the space allocation and record distribution is not perfect, the
> performance of non-indexed retrievals is degraded by the amount of
> unused space. The performance effect of non-primary index retrieval is
> more difficult to analyse because it's always bad, but assuming
> secondard indexes are orthogonal to the primary, cluster effectively
> guarantees pessimal performance on secondary indexes.

That may explain why MsSql comes with tuning utilities.