Re: avoiding seqscan?

Palle Girgensohn wrote:
> uu=# explain analyze
> uu-# select lower(substr(p.last_name,1,1)) as letter, count(*)
> uu-# FROM course c join group_data gd on (c.active_group_id =
> gd.this_group_id)
> uu-# join person p on (gd.item_text = p.userid)
> uu-# join dyn_field_person dfp on (dfp.extern_item_id = 10 and
> dfp.giver=c.giver)
> uu-# join dyn_field_content_person dfcp on (dfp.id =
> dfcp.dyn_field_id and dfcp.userid=p.userid)
> uu-# left outer join participant pt on (pt.userid = p.userid and
> pt.course_id = 707)
> uu-# WHERE c.id = 707
> uu-# group by 1
> uu-# ;

Why are you using this form of join ? When and if is not necessary use
the implicit form.

Regards
Gaetano Mendola