Re: [HACKERS] indexing words slow

> 
> > On the other hand, if I do a count(*) on '^ric', his takes consequently
> > around 1:30 mins, no matter how often I run it. This returns 7866.
> > 
> > A search on count(*) of '^lling' and '^tones' takes around 2.5 secs after
> > running it several times.
> 
> Since postgres will still read the data row (even for this count(*)) I would guess,
> that this is a data distribution problem. Maybe you could cluster your data ?
> Maybe the '^rol' rows stick pretty much together, whilst the '^ric' rows 
> are evenly distributed on all datapages. Of course there would be room
> for improvement if postgresql would not read the data pages, which are not needed 
> for any query that only selects columns that are part of the index.
> 

Brilliant.  I had forgotten that the data pages are accessed as well as
the index pages.  The CLUSTER command works in 6.3, so perhaps that will
change some times.

-- 
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)