#16622: django.test.TestCase slow using PostgreSQL 8.4.4
------------------------+-----------------------------------
Reporter: valhallasw | Owner: nobody
Type: Bug | Status: new
Milestone: | Component: Testing framework
Version: 1.3 | Severity: Normal
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Easy pickings: 0
UI/UX: 0 |
------------------------+-----------------------------------
Using very simple tests, such as
{{{#!python
class To_confirm_the_stable_database_contains_the_right_data(TestCase):
def test_adressen_that_should_not_exist_do_not_exist(self):
adressen = [1409, 1410, 1411, 4094]
for adres in adressen:
self.failUnlessEqual(
Adres.objects.using('stable').filter(pk=4095).count(),
0
)
}}}
results in very slow tests:
{{{
$ ./manage.py test
Creating test database for alias 'default'...
.....
----------------------------------------------------------------------
Ran 5 tests in 6.890s
OK
}}}
This is caused by `TRUNCATE` commands, which is clear when logging all
queries using pdb:
{{{
b /lib/python2.6/site-
packages/Django-1.3-py2.6.egg/django/db/backends/postgresql_psycopg2/base.py:43
commands 1
silent
import time
print "QUERY", time.time(), query
continue
continue
}}}
yields
{{{#!sql
QUERY 1313096004.8
SELECT c.relname
FROM pg_catalog.pg_class c
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace
WHERE c.relkind IN ('r', 'v', '')
AND n.nspname NOT IN ('pg_catalog', 'pg_toast')
AND pg_catalog.pg_table_is_visible(c.oid)
QUERY 1313096004.83 TRUNCATE "models_opdracht", "models_dataholder",
(...47 more...)
QUERY 1313096006.59 SELECT
setval(pg_get_serial_sequence('"models_dataholder_audit"','_audit_id'), 1,
false);
(..)
QUERY 1313096006.63 SELECT
setval(pg_get_serial_sequence('"models_groepeninfo"','id'), 1, false);
}}}
I thought I read somewhere that PostgreSQL did not support transactioned
`TRUNCATE` before 9.1, but I am unable to find the source. The
documentation suggests neither 8.4 nor 9.1 fully support transactions.
I can think of two ways to approach this problem -- one: don't use
`TRUNCATE`, use `DELETE` instead, which should work fine inside the
transaction; or two: instead of `TRUNCATE`ing in each transaction,
`TRUNCATE` before the first transaction, and roll back all further
transactions.
I was uncertain whether to file this under 'testing framework' or under
'database layer'. As the most direct effect is on testing, I chose the
former.
--
Ticket URL: <https://code.djangoproject.com/ticket/16622>
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