From 6d5709ce7dc37999a4d12c3ecf2a661afe097b2a Mon Sep 17 00:00:00 2001
From: Keryn Knight <keryn@kerynknight.com>
Date: Mon, 2 Aug 2021 12:05:13 +0100
Subject: [PATCH] Refs #27624 -- Optimized sql.Query creation by moving
immutable/singleton attributes to class attributes.
---
django/db/models/sql/query.py | 121 +++++++++++++++++-----------------
1 file changed, 62 insertions(+), 59 deletions(-)
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index 2b1f6757ba..1faf98d45d 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -155,6 +155,66 @@ class Query(BaseExpression):
base_table_class = BaseTable
join_class = Join
+ default_cols = True
+ default_ordering = True
+ standard_ordering = True
+
+ filter_is_sticky = False
+ subquery = False
+
+ # SQL-related attributes.
+ # Select and related select clauses are expressions to use in the SELECT
+ # clause of the query. The select is used for cases where we want to set up
+ # the select clause to contain other than default fields (values(),
+ # subqueries...). Note that annotations go to annotations dictionary.
+ select = ()
+ # The group_by attribute can have one of the following forms:
+ # - None: no group by at all in the query
+ # - A tuple of expressions: group by (at least) those expressions.
+ # String refs are also allowed for now.
+ # - True: group by all select fields of the model
+ # See compiler.get_group_by() for details.
+ group_by = None
+ order_by = ()
+ low_mark = 0 # Used for offset/limit.
+ high_mark = None # Used for offset/limit.
+ distinct = False
+ distinct_fields = ()
+ select_for_update = False
+ select_for_update_nowait = False
+ select_for_update_skip_locked = False
+ select_for_update_of = ()
+ select_for_no_key_update = False
+ select_related = False
+ # Arbitrary limit for select_related to prevents infinite recursion.
+ max_depth = 5
+ # Holds the selects defined by a call to values() or values_list()
+ # excluding annotation_select and extra_select.
+ values_select = ()
+
+ # SQL annotation-related attributes.
+ annotation_select_mask = None
+ _annotation_select_cache = None
+
+ # Set combination attributes.
+ combinator = None
+ combinator_all = False
+ combined_queries = ()
+
+ # These are for extensions. The contents are more or less appended verbatim
+ # to the appropriate clause.
+ extra_select_mask = None
+ _extra_select_cache = None
+
+ extra_tables = ()
+ extra_order_by = ()
+
+ # A tuple that is a set of model field names and either True, if these are
+ # the fields to defer, or False if these are the only fields to load.
+ deferred_loading = (frozenset(), True)
+
+ explain_info = None
+
def __init__(self, model, alias_cols=True):
self.model = model
self.alias_refcount = {}
@@ -172,74 +232,17 @@ class Query(BaseExpression):
# Map external tables to whether they are aliased.
self.external_aliases = {}
self.table_map = {} # Maps table names to list of aliases.
- self.default_cols = True
- self.default_ordering = True
- self.standard_ordering = True
self.used_aliases = set()
- self.filter_is_sticky = False
- self.subquery = False
- # SQL-related attributes
- # Select and related select clauses are expressions to use in the
- # SELECT clause of the query.
- # The select is used for cases where we want to set up the select
- # clause to contain other than default fields (values(), subqueries...)
- # Note that annotations go to annotations dictionary.
- self.select = ()
self.where = WhereNode()
- # The group_by attribute can have one of the following forms:
- # - None: no group by at all in the query
- # - A tuple of expressions: group by (at least) those expressions.
- # String refs are also allowed for now.
- # - True: group by all select fields of the model
- # See compiler.get_group_by() for details.
- self.group_by = None
- self.order_by = ()
- self.low_mark, self.high_mark = 0, None # Used for offset/limit
- self.distinct = False
- self.distinct_fields = ()
- self.select_for_update = False
- self.select_for_update_nowait = False
- self.select_for_update_skip_locked = False
- self.select_for_update_of = ()
- self.select_for_no_key_update = False
-
- self.select_related = False
- # Arbitrary limit for select_related to prevents infinite recursion.
- self.max_depth = 5
-
- # Holds the selects defined by a call to values() or values_list()
- # excluding annotation_select and extra_select.
- self.values_select = ()
-
- # SQL annotation-related attributes
- self.annotations = {} # Maps alias -> Annotation Expression
- self.annotation_select_mask = None
- self._annotation_select_cache = None
-
- # Set combination attributes
- self.combinator = None
- self.combinator_all = False
- self.combined_queries = ()
-
+ # Maps alias -> Annotation Expression.
+ self.annotations = {}
# These are for extensions. The contents are more or less appended
# verbatim to the appropriate clause.
self.extra = {} # Maps col_alias -> (col_sql, params).
- self.extra_select_mask = None
- self._extra_select_cache = None
-
- self.extra_tables = ()
- self.extra_order_by = ()
-
- # A tuple that is a set of model field names and either True, if these
- # are the fields to defer, or False if these are the only fields to
- # load.
- self.deferred_loading = (frozenset(), True)
self._filtered_relations = {}
- self.explain_info = None
-
@property
def output_field(self):
if len(self.select) == 1: