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Code Issues 32 Releases Wiki Activity

Fixed an isnull=False filtering edge-case. Fixes #15316.

Browse Source 
The bulk of this patch is due to some fine analysis from Aleksandra
Sendecka.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16656 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Malcolm Tredinnick
2011-08-23 03:38:42 +00:00
parent c3a0dcf6e9
commit 2e56066a5b
4 changed files with 168 additions and 8 deletions
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19
django/db/models/sql/query.py
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@@ -1105,7 +1105,10 @@ class Query(object):
# Process the join list to see if we can remove any inner joins from
# the far end (fewer tables in a query is better).
col, alias, join_list = self.trim_joins(target, join_list, last, trim)
nonnull_comparison = (lookup_type == 'isnull' and value is False)
col, alias, join_list = self.trim_joins(target, join_list, last, trim,
nonnull_comparison)
if connector == OR:
# Some joins may need to be promoted when adding a new filter to a
# disjunction. We walk the list of new joins and where it diverges
@@ -1442,7 +1445,7 @@ class Query(object):
return field, target, opts, joins, last, extra_filters
def trim_joins(self, target, join_list, last, trim):
def trim_joins(self, target, join_list, last, trim, nonnull_check=False):
"""
Sometimes joins at the end of a multi-table sequence can be trimmed. If
the final join is against the same column as we are comparing against,
@@ -1463,6 +1466,11 @@ class Query(object):
trimmed before anything. See the documentation of add_filter() for
details about this.
The 'nonnull_check' parameter is True when we are using inner joins
between tables explicitly to exclude NULL entries. In that case, the
tables shouldn't be trimmed, because the very action of joining to them
alters the result set.
Returns the final active column and table alias and the new active
join_list.
"""
@@ -1470,7 +1478,7 @@ class Query(object):
penultimate = last.pop()
if penultimate == final:
penultimate = last.pop()
if trim and len(join_list) > 1:
if trim and final > 1:
extra = join_list[penultimate:]
join_list = join_list[:penultimate]
final = penultimate
@@ -1483,12 +1491,13 @@ class Query(object):
alias = join_list[-1]
while final > 1:
join = self.alias_map[alias]
if col != join[RHS_JOIN_COL] or join[JOIN_TYPE] != self.INNER:
if (col != join[RHS_JOIN_COL] or join[JOIN_TYPE] != self.INNER or
nonnull_check):
break
self.unref_alias(alias)
alias = join[LHS_ALIAS]
col = join[LHS_JOIN_COL]
join_list = join_list[:-1]
join_list.pop()
final -= 1
if final == penultimate:
penultimate = last.pop()