Re: How is possible that avg_data_blocks_per_key = 0 even with fresh statistics ?

On Dec 6, 8:13 am, nicola.far..._at_info-line.it wrote:
> But you're right, I forgot important details: the two tables aren't
> empty, they contain 9 and 13 rows respectively.
> Statistics are collected every morning and table contents didn't
> change since then.
> The index involved is, by the way, the primary key.
>
> On the slow site I tried collecting system statistics for a short time
> (20 minutes) and I observe now a gain in performance on the slow
> query
> (25000 consistent gets now instead of more than 150k). The plan is so
> big that is difficult to see the difference (but who cares if the
> query run at speed ?)
> No system stats are in place on the site #2
>
> Still I don't understand how index statistics on site #2 can be
> empty ......????
>
>
>
> > Sorry just not enough caffeine in me yet. Maybe the table at one site
> > was truncated/empty when the stats were gathered?
>
> > That way the stats "can be current" yet still useless and not helpful
> > to the optimizer after data has been placed into the table.- Hide quoted text -
>
> - Show quoted text -

How, exactly, are you generating these statistics? Please post the command you're using.

David Fitzjarrell Received on Thu Dec 06 2007 - 09:32:32 CST