Em Seg, 2004-12-13 às 16:03, Bruno Wolff III escreveu:
> On Mon, Dec 13, 2004 at 15:17:49 -0200,
> Alvaro Nunes Melo <al_nunes@atua.com.br> wrote:
> > db=> SELECT COUNT(*) FROM titulo WHERE cd_pessoa = 1;
> > count
> > -------
> > 220
> > (1 record)
> >
> > Time: 48,762 ms
> > db=> SELECT COUNT(*) FROM movimento WHERE cd_pessoa = 1;
> > count
> > -------
> > 221
> > (1 record)
> >
> > Time: 1158,463 ms
>
> I suspect you have a lot of dead tuples in those tables.
> Have you vacuumed them recently?
> Was there enough FSM space when you did so?
>
> You might try doing VACUUM FULL on each table now and see if that
> fixes the problem.
The table had not too many tuples delete, but I runned a VACUUM FULL
VERBOSE ANALYZE and the query's cost and execution time are stil the
same. The output was:
INFO: vacuuming "public.movimento"
INFO: "movimento": found 13 removable, 347355 nonremovable row versions
in 3251 pages
DETAIL: 0 dead row versions cannot be removed yet.
Nonremovable row versions range from 68 to 74 bytes long.
There were 0 unused item pointers.
Total free space (including removable row versions) is 131440 bytes.
0 pages are or will become empty, including 0 at the end of the table.
90 pages containing 14824 free bytes are potential move destinations.
CPU 0.06s/0.03u sec elapsed 0.81 sec.
INFO: index "idx_movimento_cd_pessoa" now contains 347355 row versions
in 764 pages
DETAIL: 13 index row versions were removed.
0 index pages have been deleted, 0 are currently reusable.
CPU 0.01s/0.02u sec elapsed 0.18 sec.
INFO: index "pk_movimento" now contains 347355 row versions in 764
pages
DETAIL: 13 index row versions were removed.
0 index pages have been deleted, 0 are currently reusable.
CPU 0.02s/0.02u sec elapsed 0.39 sec.
INFO: index "idx_movimento_cd_pessoa_id_tipo" now contains 347355 row
versions in 956 pages
DETAIL: 0 index row versions were removed.
0 index pages have been deleted, 0 are currently reusable.
CPU 0.02s/0.03u sec elapsed 0.27 sec.
INFO: "movimento": moved 9 row versions, truncated 3251 to 3250 pages
DETAIL: CPU 0.00s/0.00u sec elapsed 0.37 sec.
INFO: index "idx_movimento_cd_pessoa" now contains 347355 row versions
in 764 pages
DETAIL: 9 index row versions were removed.
0 index pages have been deleted, 0 are currently reusable.
CPU 0.02s/0.02u sec elapsed 0.08 sec.
INFO: index "pk_movimento" now contains 347355 row versions in 764
pages
DETAIL: 9 index row versions were removed.
0 index pages have been deleted, 0 are currently reusable.
CPU 0.02s/0.02u sec elapsed 0.04 sec.
INFO: index "idx_movimento_cd_pessoa_id_tipo" now contains 347355 row
versions in 956 pages
DETAIL: 9 index row versions were removed.
0 index pages have been deleted, 0 are currently reusable.
CPU 0.02s/0.02u sec elapsed 0.07 sec.
INFO: vacuuming "pg_toast.pg_toast_31462037"
INFO: "pg_toast_31462037": found 0 removable, 0 nonremovable row
versions in 0 pages
DETAIL: 0 dead row versions cannot be removed yet.
Nonremovable row versions range from 0 to 0 bytes long.
There were 0 unused item pointers.
Total free space (including removable row versions) is 0 bytes.
0 pages are or will become empty, including 0 at the end of the table.
0 pages containing 0 free bytes are potential move destinations.
CPU 0.00s/0.00u sec elapsed 0.00 sec.
INFO: index "pg_toast_31462037_index" now contains 0 row versions in 1
pages
DETAIL: 0 index pages have been deleted, 0 are currently reusable.
CPU 0.00s/0.00u sec elapsed 0.01 sec.
INFO: analyzing "public.movimento"
INFO: "movimento": 3250 pages, 3000 rows sampled, 347170 estimated
total rows


--
+---------------------------------------------------+
| Alvaro Nunes Melo Atua Sistemas de Informacao |
| al_nunes@atua.com.br www.atua.com.br |
| UIN - 42722678 (54) 327-1044 |
+---------------------------------------------------+


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TIP 7: don't forget to increase your free space map settings

On Mon, Dec 13, 2004 at 17:32:02 -0200,
Alvaro Nunes Melo <al_nunes@atua.com.br> wrote:
> Em Seg, 2004-12-13 às 16:03, Bruno Wolff III escreveu:
> > On Mon, Dec 13, 2004 at 15:17:49 -0200,
> > Alvaro Nunes Melo <al_nunes@atua.com.br> wrote:
> > > db=> SELECT COUNT(*) FROM titulo WHERE cd_pessoa = 1;
> > > count
> > > -------
> > > 220
> > > (1 record)
> > >
> > > Time: 48,762 ms
> > > db=> SELECT COUNT(*) FROM movimento WHERE cd_pessoa = 1;
> > > count
> > > -------
> > > 221
> > > (1 record)
> > >
> > > Time: 1158,463 ms
> >
> > I suspect you have a lot of dead tuples in those tables.
> > Have you vacuumed them recently?
> > Was there enough FSM space when you did so?
> >
> > You might try doing VACUUM FULL on each table now and see if that
> > fixes the problem.
> The table had not too many tuples delete, but I runned a VACUUM FULL
> VERBOSE ANALYZE and the query's cost and execution time are stil the
> same. The output was:
> INFO: vacuuming "public.movimento"
> INFO: "movimento": found 13 removable, 347355 nonremovable row versions
> in 3251 pages

If the table really has 300K rows, then something else is wrong. One likely
candidate is if cd_pessoa is int8 there is a quirk in postgres (which is
fixed in 8.0) where comparing that column to an int4 constant won't use
an index scan. This can be worked around by either casting the constant
(e.g. 1::int8) or quoting it (e.g. '1') to delay fixing the type so that
it will be taken to be an int8 constant.

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TIP 8: explain analyze is your friend