My guess is that indexed values are compressed based on the prior index
value, therefore you have to traverse them in a forward direction, otherwise
they would be inefficient e.g.

Index of
AAAAAA
AAAAAB
AAAAAC
ABDFGH
looks like
AAAAAA
Same 4 + B
Same 4 + C
Same 1 +BDFGH

JAC


"Szak�ly Bal�zs" <szakalyb@...> wrote in message
news:000101c1ffef$e2de4a50$0c00a8c0@SZAKALYB...

> Why cannot use FB any index on select with desc order?
>
> Select * from TTT order by FFF desc
>
> There is an index to fff but not desc order. Why cannot use in this
> case?=20
> So, i need to create 2 indexes to all table, where i need desc order
> with high response time.
>
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