> > Index BigTable_IDX2 (6)
> > Depth: 3, leaf buckets: 2406, nodes: 3264049
> > Average data length: 0.00, total dup: 3264039, max dup: 3166674
> > Fill distribution:
> > 0 - 19% = 0
> > 20 - 39% = 1
> > 40 - 59% = 0
> > 60 - 79% = 0
> > 80 - 99% = 2405
> >
> >Not sure what all that means, or where to find out what that all
> >means...
>
> It means that, of 3264049 nodes (rows where the index value isn't null) you
> have
> 3166674 all of one single value and only about 97,000 of other
> values. That is a single chain of more than 3 million. That screams "drop
> me!! with a compelling shrillness. If it's a FK, drop the constraint.

Since NULLs are indexed they should count as nodes too.
(Just by looking at statistics you can't say whether some nodes
or even all 3166674 max. duplicates are null or not.)

Ivan