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Cleaned up join promotion in query.combine() with OR 

Refs #19849
This commit is contained in:
Anssi Kääriäinen 2013-02-19 12:46:11 +02:00
parent edf93127bf
commit 10f9ba046f
1 changed files with 7 additions and 23 deletions
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30
django/db/models/sql/query.py
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@ -524,31 +524,15 @@ class Query(object):
# the join type for the unused alias.
self.unref_alias(new_alias)
# So that we don't exclude valid results in an "or" query combination,
# So that we don't exclude valid results in an OR query combination,
# all joins exclusive to either the lhs or the rhs must be converted
# to an outer join.
# to an outer join. RHS joins were already set to outer joins above,
# so check which joins were used only in the lhs query.
if not conjunction:
l_tables = set(self.tables)
r_tables = set(rhs.tables)
# Update r_tables aliases.
for alias in change_map:
if alias in r_tables:
# r_tables may contain entries that have a refcount of 0
# if the query has references to a table that can be
# trimmed because only the foreign key is used.
# We only need to fix the aliases for the tables that
# actually have aliases.
if rhs.alias_refcount[alias]:
r_tables.remove(alias)
r_tables.add(change_map[alias])
# Find aliases that are exclusive to rhs or lhs.
# These are promoted to outer joins.
outer_tables = (l_tables | r_tables) - (l_tables & r_tables)
for alias in outer_tables:
# Again, some of the tables won't have aliases due to
# the trimming of unnecessary tables.
if self.alias_refcount.get(alias) or rhs.alias_refcount.get(alias):
self.promote_joins([alias], True)
rhs_used_joins = set(change_map.values())
to_promote = [alias for alias in self.tables
if alias not in rhs_used_joins]
self.promote_joins(to_promote, True)
# Now relabel a copy of the rhs where-clause and add it to the current
# one.