dear ivan,

i will do the test, i m a little surprised that we can not use index on big table ... in this way how to order record in very big table ?

thanks again
stephane

--- In firebird-support@yahoogroups.com, "Ivan Prenosil" <Ivan.Prenosil@...> wrote:
>
> >> > in this table around 50 000 000 records (and 20 fields)
> >> >
> >> > this index are motly here because we need to handle search and order for client in < 100 ms. so we need to index all possible
> >> > case
> >> > of search
> >>
> >> But ordering using index is quite slow on the table of that size, your quieries will usually be slower than 100 ms anyway.
>
> > by ordering using index is slow, you mean in the insert (updating the index) or you mean in the select (using the select) ?
>
> Yes, SELECT. Can you try yourself ? Construct SELECT statement with WHERE clause that will return e.g. 150 rows,
> and execute it on your 50 000 000 records table, once ORDERed by index, once withou index, and compare the times.
> (and use different fields for search condition and for ordering)
> (for easy switching between ordering with/without index, use ASC/DESC in your order clause)
>
> Ivan
> http://www.volny.cz/iprenosil/interbase/
>