Query on Postgres totaly holds down server - postgresql

Question

Now, I'am moving our database from Microsoft SQL Server to PostgreSQL 9.1.
There are a simple query, to calculate some summary of our store:
SELECT DISTINCT p.part_name_id,
(SELECT SUM(p1.quantity)
FROM parts.spareparts p1
WHERE p1.part_name_id = p.part_name_id) AS AllQuantity,
(SELECT SUM(p2.price * p2.quantity)
FROM parts.spareparts p2
WHERE p2.part_name_id = p.part_name_id) AS AllPrice
FROM parts.spareparts p
It working very fast on MSSQL, less than one second, there are about 150 000 records in spareparts table.
In PostgreSQL I waited for 200,000 milliseconds and not wait for the result.
Where I was wrong?
P.S.: table definitions:
-- Table: parts.spareparts
-- DROP TABLE parts.spareparts;
CREATE TABLE parts.spareparts
(
id serial NOT NULL,
big_id bigint NOT NULL,
part_unique integer NOT NULL,
store_address integer,
brand_id integer,
model_id integer,
category_id integer,
part_name_id integer,
price money,
quantity integer,
description character varying(250),
private_info character varying(600),
manager_id integer,
company_id integer,
part_type smallint,
box_number integer,
com_person character varying(200),
com_phone character varying(200),
vendor_id integer,
is_publish boolean DEFAULT true,
is_comission boolean DEFAULT false,
is_new boolean DEFAULT false,
is_warning boolean DEFAULT false,
catalog_no character varying(200),
disc_id integer,
is_set boolean,
w_height numeric(3,2),
w_width numeric(3,2),
w_diam numeric(3,2),
w_type integer,
page_url character varying(150),
last_edit_manager_id integer,
CONSTRAINT spareparts_pk PRIMARY KEY (id)
)
WITH (
OIDS=FALSE
);
ALTER TABLE parts.spareparts
OWNER TO asap;
-- Index: parts.sparepart_part_unique_idx
-- DROP INDEX parts.sparepart_part_unique_idx;
CREATE INDEX sparepart_part_unique_idx
ON parts.spareparts
USING btree
(part_unique, company_id);
-- Index: parts.spareparts_4param_idx
-- DROP INDEX parts.spareparts_4param_idx;
CREATE INDEX spareparts_4param_idx
ON parts.spareparts
USING btree
(brand_id, model_id, category_id, part_name_id);
-- Index: parts.spareparts_bigid_idx
-- DROP INDEX parts.spareparts_bigid_idx;
CREATE INDEX spareparts_bigid_idx
ON parts.spareparts
USING btree
(big_id);
-- Index: parts.spareparts_brand_id_part_id_quantity_idx
-- DROP INDEX parts.spareparts_brand_id_part_id_quantity_idx;
CREATE INDEX spareparts_brand_id_part_id_quantity_idx
ON parts.spareparts
USING btree
(brand_id, part_name_id, quantity);
-- Index: parts.spareparts_brand_id_quantity_idx
-- DROP INDEX parts.spareparts_brand_id_quantity_idx;
CREATE INDEX spareparts_brand_id_quantity_idx
ON parts.spareparts
USING btree
(brand_id, quantity);
-- Index: parts.spareparts_company_id_part_unique_idx
-- DROP INDEX parts.spareparts_company_id_part_unique_idx;
CREATE INDEX spareparts_company_id_part_unique_idx
ON parts.spareparts
USING btree
(company_id, part_unique);
-- Index: parts.spareparts_model_id_company_id
-- DROP INDEX parts.spareparts_model_id_company_id;
CREATE INDEX spareparts_model_id_company_id
ON parts.spareparts
USING btree
(model_id, company_id);
COMMENT ON INDEX parts.spareparts_model_id_company_id
IS 'Для frmFilter';
-- Index: parts.spareparts_url_idx
-- DROP INDEX parts.spareparts_url_idx;
CREATE INDEX spareparts_url_idx
ON parts.spareparts
USING btree
(page_url COLLATE pg_catalog."default");
-- Trigger: spareparts_delete_trigger on parts.spareparts
-- DROP TRIGGER spareparts_delete_trigger ON parts.spareparts;
CREATE TRIGGER spareparts_delete_trigger
AFTER DELETE
ON parts.spareparts
FOR EACH ROW
EXECUTE PROCEDURE parts.spareparts_delete_fn();
-- Trigger: spareparts_update_trigger on parts.spareparts
-- DROP TRIGGER spareparts_update_trigger ON parts.spareparts;
CREATE TRIGGER spareparts_update_trigger
AFTER INSERT OR UPDATE
ON parts.spareparts
FOR EACH ROW
EXECUTE PROCEDURE parts.spareparts_update_fn();

Answer 1

I think you can rewrite the query without the need of the nested selects:
SELECT p.part_name_id,
SUM(p.quantity) AS AllQuantity,
SUM(p.price * p.quantity) AS AllPrice
FROM parts.spareparts p
group by p.part_name_id

Answer 2

I don't think you actually need the subqueries; you can write simply:
SELECT part_name_id,
SUM(quantity) AS AllQuantity,
SUM(price * quantity) AS AllPrice
FROM parts.spare_parts
GROUP
BY part_name_id
;
which should be much more efficient.