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Greetings,
It seems that stored procedures that
use SETOF are slower than regular sql
commands. Why does it
happens?
Please check out the following example.
bxs=# \d
cham_chamada
Table "public.cham_chamada"
Column | Type |
Modifiers
-------------------+--------------------------------+-----------
dt_inicial
| timestamp(0) without time zone | not null
cod_bxs | integer | not
null
chave | integer | not null
identificacao | integer | not
null
identidadea | character varying(25)
....
Indexes:
xpkcham_chamada primary key btree (dt_inicial, cod_bxs,
chave,
identificacao),
bxs=# SELECT COUNT(*) FROM
cham_chamada;
count
--------
392858
(1 row)
CREATE TYPE
rec_teste AS (dt_inicial timestamp(0), identidadea
varchar(25));
CREATE OR REPLACE FUNCTION teste() RETURNS SETOF
rec_teste AS'
SELECT dt_inicial, identidadea
FROM cham_chamada
cc;'
LANGUAGE SQL;
bxs=# EXPLAIN ANALYZE SELECT dt_inicial,
identidadea FROM cham_chamada cc;
QUERY
PLAN
----------------------------------------------------------------------------
---------------------------------------------------------
Seq
Scan on cham_chamada cc (cost=100000000.00..100011071.72
rows=358772
width=18) (actual time=0.29..2887.40 rows=392631
loops=1)
Total runtime: 3092.28 msec
(2 rows)
bxs=# EXPLAIN
ANALYZE SELECT * FROM teste();
QUERY
PLAN
----------------------------------------------------------------------------
----------------------------------------
Function
Scan on teste (cost=0.00..12.50 rows=1000 width=37)
(actual
time=17527.53..18326.71 rows=392631 loops=1)
Total runtime:
18595.13 msec
(2 rows)
For the same sql script, execution time
is almost 20sec. Compared with
execution time of regular sql script,
there is a huge difference. I already
tested with other complexity
levels (left joins, indexed and sequencial scan
queries etc) and some
times I got 100 times slower when executing inside
stored procedure.
Could you give me some light?
Thanks in advance.
José
Vilson de Mello de Farias
Analista de Sistemas - APC
DÍGITRO
TECNOLOGIA
E-mail: [EMAIL PROTECTED]
Fone:
(0xx48) 281-7158
Fax: (0xx48) 281-7000
Site: www.digitro.com.br
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