ensure anon_map is passed for most annotated traversals

We can cache the annotated cache key for Table, but
for selectables it's not safe, as it fails to pass the
anon_map along and creates many redudant structures in
observed test scenario.  It is likely safe for a
Column that's mapped to a Table also, however this is
not implemented here.   Will have to see if that part
needs adjusting.

Fixed critical memory issue identified in cache key generation, where for
very large and complex ORM statements that make use of lots of ORM aliases
with subqueries, cache key generation could produce excessively large keys
that were orders of magnitude bigger than the statement itself. Much thanks
to Rollo Konig Brock for their very patient, long term help in finally
identifying this issue.

Also within TypeEngine objects, when we generate elements
for instance variables, skip the None elements at least.
this also saves on tuple complexity.

Fixes: #8790
Change-Id: I448ddbfb45ae0a648815be8dad4faad7d1977427
(cherry picked from commit 88c240d907a9ae3b5caf766009edd196a30cece3)

1 files changed, 10 insertions, 6 deletions

diff --git a/lib/sqlalchemy/sql/traversals.py b/lib/sqlalchemy/sql/traversals.py
index 9da61ab28..21aa17a0a 100644
--- a/lib/sqlalchemy/sql/traversals.py
+++ b/lib/sqlalchemy/sql/traversals.py
@@ -246,12 +246,16 @@ class HasCacheKey(object):
                             else None,
                         )
                     elif meth is InternalTraversal.dp_annotations_key:
-                        # obj is here is the _annotations dict.   however, we
-                        # want to use the memoized cache key version of it. for
-                        # Columns, this should be long lived.   For select()
-                        # statements, not so much, but they usually won't have
-                        # annotations.
-                        result += self._annotations_cache_key
+                        # obj is here is the _annotations dict.  Table uses
+                        # a memoized version of it.  however in other cases,
+                        # we generate it given anon_map as we may be from a
+                        # Join, Aliased, etc.
+                        # see #8790
+
+                        if self._gen_static_annotations_cache_key:  # type: ignore  # noqa: E501
+                            result += self._annotations_cache_key  # type: ignore  # noqa: E501
+                        else:
+                            result += self._gen_annotations_cache_key(anon_map)  # type: ignore  # noqa: E501
                     elif (
                         meth is InternalTraversal.dp_clauseelement_list
                         or meth is InternalTraversal.dp_clauseelement_tuple