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[1.11.x] Fixed #28817 -- Made QuerySet.iterator() use server-side cursors after values() and values_list().

Backport of d97f026a7ab5212192426e45121f7a52751a2044 from master
This commit is contained in:
Dražen Odobašić 2017-11-19 10:13:10 -05:00 committed by Tim Graham
parent 90c120c2b7
commit 7f4e174511
4 changed files with 23 additions and 7 deletions

View File

@ -103,7 +103,7 @@ class ValuesIterable(BaseIterable):
# extra(select=...) cols are always at the start of the row.
names = extra_names + field_names + annotation_names
for row in compiler.results_iter():
for row in compiler.results_iter(chunked_fetch=self.chunked_fetch):
yield dict(zip(names, row))
@ -119,7 +119,7 @@ class ValuesListIterable(BaseIterable):
compiler = query.get_compiler(queryset.db)
if not query.extra_select and not query.annotation_select:
for row in compiler.results_iter():
for row in compiler.results_iter(chunked_fetch=self.chunked_fetch):
yield tuple(row)
else:
field_names = list(query.values_select)
@ -135,7 +135,7 @@ class ValuesListIterable(BaseIterable):
else:
fields = names
for row in compiler.results_iter():
for row in compiler.results_iter(chunked_fetch=self.chunked_fetch):
data = dict(zip(names, row))
yield tuple(data[f] for f in fields)
@ -149,7 +149,7 @@ class FlatValuesListIterable(BaseIterable):
def __iter__(self):
queryset = self.queryset
compiler = queryset.query.get_compiler(queryset.db)
for row in compiler.results_iter():
for row in compiler.results_iter(chunked_fetch=self.chunked_fetch):
yield row[0]

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@ -833,12 +833,12 @@ class SQLCompiler(object):
row[pos] = value
return tuple(row)
def results_iter(self, results=None):
def results_iter(self, results=None, chunked_fetch=False):
"""
Returns an iterator over the results from executing this query.
"""
if results is None:
results = self.execute_sql(MULTI)
results = self.execute_sql(MULTI, chunked_fetch=chunked_fetch)
fields = [s[0] for s in self.select[0:self.col_count]]
converters = self.get_converters(fields)
for rows in results:

View File

@ -18,3 +18,6 @@ Bugfixes
* Fixed incorrect index name truncation when using a namespaced ``db_table``
(:ticket:`28792`).
* Made ``QuerySet.iterator()`` use server-side cursors on PostgreSQL after
``values()`` and ``values_list()`` (:ticket:`28817`).

View File

@ -3,7 +3,7 @@ import unittest
from collections import namedtuple
from contextlib import contextmanager
from django.db import connection
from django.db import connection, models
from django.test import TestCase
from .models import Person
@ -53,6 +53,19 @@ class ServerSideCursorsPostgres(TestCase):
def test_server_side_cursor(self):
self.assertUsesCursor(Person.objects.iterator())
def test_values(self):
self.assertUsesCursor(Person.objects.values('first_name').iterator())
def test_values_list(self):
self.assertUsesCursor(Person.objects.values_list('first_name').iterator())
def test_values_list_flat(self):
self.assertUsesCursor(Person.objects.values_list('first_name', flat=True).iterator())
def test_values_list_fields_not_equal_to_names(self):
expr = models.Count('id')
self.assertUsesCursor(Person.objects.annotate(id__count1=expr).values_list(expr, 'id__count1').iterator())
def test_server_side_cursor_many_cursors(self):
persons = Person.objects.iterator()
persons2 = Person.objects.iterator()