Re: Premature view materialization in 8.2? - Mailing list pgsql-performance

From Jonathan Ellis
Subject Re: Premature view materialization in 8.2?
Date
Msg-id e06563880704061103w10e19b96s4223527ebce6b33b@mail.gmail.com
Whole thread Raw
In response to Re: Premature view materialization in 8.2?  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Premature view materialization in 8.2?
List pgsql-performance
On 4/6/07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> "Jonathan Ellis" <jonathan@utahpython.org> writes:
> > I can do that...  you don't think the fact I mentioned, that
> > redefining the view to leave out the expensive function fixes the
> > problem, is relevant?
>
> Hm, I'd not have thought that an expensive function would get evaluated
> partway up the join tree, but maybe that's wrong.  You never did show
> us the actual view definition ...

It was in my original post unless it got clipped:

The problem seems to be that clan_members_v contains a call to an
expensive function:

create or replace view clan_members_v as
select cm.clan_id, cm.user_id, cp.party_id, cm.date_accepted,
  p.name as party_name, p_tp_total(p.id)::int as tp_total
from clan_members cm, clan_participants cp, parties p
where cm.user_id = p.user_id
and p.id = cp.party_id
;

p_tp_total takes around 50ms per row.

If I create clan_members_v without the function call, the original
query's speed goes to the 150ms range on 8.2 as well.

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