Re: Performance question
In article <6d4d1d$i97$1@news.EUnet.pt>,
Rui Domingos <rui.domingos@psidoc.pt> wrote:
>
>This is true because Informix doesn't use indexes in the presence of an or
>operation.
>So if table1 is big and you have an index on col the UNION example will work
>much faster, because now you have 3 selects but no ORs.
>
>Rui Domingos
>rui.domingos@psidoc.pt
You know, I wonder if this is really true. Everyone says it, and yet my
query
select rev_ref_num
from asap_rev_extract
where ( ext_id = 3840000 or ext_id = 383000 )
comes back instantly. 3.5M rows, index on ext_id...
I'm using OnLine 7.3
Paul (not a spokesman)