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Code Issues 25 Releases Wiki Activity

Fixed #30494 -- Disabled __year lookup optimization for indirect values.

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The previous heuristics were naively enabling the BETWEEN optimization on
successful cast of the first rhs SQL params to an integer while it was
not appropriate for a lot of database resolved expressions.

Thanks Alexey Chernov for the report.
This commit is contained in:
Simon Charette 2019-05-20 18:53:13 -04:00 committed by Mariusz Felisiak
parent 1d0bab0bfd
commit 4d1420947e
2 changed files with 20 additions and 16 deletions
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25
django/db/models/lookups.py
View File

@ -508,21 +508,16 @@ class YearExact(YearLookup, Exact):
lookup_name = 'exact'
def as_sql(self, compiler, connection):
# We will need to skip the extract part and instead go
# directly with the originating field, that is self.lhs.lhs.
lhs_sql, params = self.process_lhs(compiler, connection, self.lhs.lhs)
rhs_sql, rhs_params = self.process_rhs(compiler, connection)
try:
# Check that rhs_params[0] exists (IndexError),
# it isn't None (TypeError), and is a number (ValueError)
int(rhs_params[0])
except (IndexError, TypeError, ValueError):
# Can't determine the bounds before executing the query, so skip
# optimizations by falling back to a standard exact comparison.
return super().as_sql(compiler, connection)
bounds = self.year_lookup_bounds(connection, rhs_params[0])
params.extend(bounds)
return '%s BETWEEN %%s AND %%s' % lhs_sql, params
# Avoid the extract operation if the rhs is a direct value to allow
# indexes to be used.
if self.rhs_is_direct_value():
# Skip the extract part by directly using the originating field,
# that is self.lhs.lhs.
lhs_sql, params = self.process_lhs(compiler, connection, self.lhs.lhs)
bounds = self.year_lookup_bounds(connection, self.rhs)
params.extend(bounds)
return '%s BETWEEN %%s AND %%s' % lhs_sql, params
return super().as_sql(compiler, connection)
class YearGt(YearComparisonLookup):

11
tests/db_functions/datetime/test_extract_trunc.py
View File

@ -4,7 +4,8 @@ import pytz
from django.conf import settings
from django.db.models import (
DateField, DateTimeField, IntegerField, Max, OuterRef, Subquery, TimeField,
DateField, DateTimeField, F, IntegerField, Max, OuterRef, Subquery,
TimeField,
)
from django.db.models.functions import (
Extract, ExtractDay, ExtractHour, ExtractIsoYear, ExtractMinute,
@ -108,6 +109,14 @@ class DateFunctionTests(TestCase):
query_string = str(qs.query).lower()
self.assertEqual(query_string.count(' between '), 1)
self.assertEqual(query_string.count('extract'), 0)
# an expression rhs cannot use the between optimization.
qs = DTModel.objects.annotate(
start_year=ExtractYear('start_datetime'),
).filter(end_datetime__year=F('start_year') + 1)
self.assertEqual(qs.count(), 1)
query_string = str(qs.query).lower()
self.assertEqual(query_string.count(' between '), 0)
self.assertEqual(query_string.count('extract'), 3)
def test_extract_year_greaterthan_lookup(self):
start_datetime = datetime(2015, 6, 15, 14, 10)