Premature view materialization in 8.2?

From: "Jonathan Ellis" <jonathan(at)utahpython(dot)org>
To: pgsql-performance(at)postgresql(dot)org
Subject: Premature view materialization in 8.2?
Date: 2007-04-05 18:46:08
Message-ID: e06563880704051146r357cb15by7e498c6d796b093a@mail.gmail.com
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I have a query hitting a view that takes 0.15s on 8.1 but 6s on 8.2.3:

select party_id from clan_members_v cm, clans c
where cm.clan_id = c.id
and c.type = 'standard'

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.

Is this a regression, or a "feature" of 8.2?

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