Re: [HACKERS] please help on query

On Mon, 15 Jul 2002 09:45:36 +0200
"Luis Alberto Amigo Navarro" <lamigo(at)atc(dot)unican(dot)es> wrote:

> This is the output:
>
> Aggregate (cost=0.00..647161.10 rows=600122 width=8) (actual
> time=4959.19..347328.83 rows=62 loops=1)
> -> Group (cost=0.00..632158.04 rows=6001225 width=8) (actual
> time=10.79..274259.16 rows=6001225 loops=1)
> -> Index Scan using lineitem_pkey on lineitem
> (cost=0.00..617154.97 rows=6001225 width=8) (actual time=10.77..162439.11
> rows=6001225 loops=1)
> Total runtime: 347330.28 msec
>
> it is returning all rows in lineitem. Why is it using index?

Sorry, I don't know the reason.
I need more info. Can you show me the outputs of EXPLAIN ANALYZE ?

EXPLAIN ANALYZE
SELECT
orders.orderkey
FROM
lineitem LEFT OUTER JOIN
orders USING(orderkey)
WHERE
orders.orderkey IS NOT NULL
GROUP BY
orders.orderkey
HAVING
SUM(lineitem.quantity) > 300;

EXPLAIN ANALYZE
SELECT
t2.*
FROM (SELECT
orders.orderkey
FROM
lineitem LEFT OUTER JOIN
orders USING(orderkey)
WHERE
orders.orderkey IS NOT NULL
GROUP BY
orders.orderkey
HAVING
SUM(lineitem.quantity) > 300
) AS t1 LEFT OUTER JOIN
orders AS t2 USING(orderkey)
ORDER BY t2.custkey

Regards,
Masaru Sugawara