From 5d0325a78b2a5f7a9109290fb23d46a841042da6 Mon Sep 17 00:00:00 2001 From: Stephen Finucane Date: Fri, 8 Apr 2022 11:38:54 +0100 Subject: [PATCH] db: Resolve additional SAWarning warnings Resolving the following SAWarning warnings: Coercing Subquery object into a select() for use in IN(); please pass a select() construct explicitly SELECT statement has a cartesian product between FROM element(s) "foo" and FROM element "bar". Apply join condition(s) between each element to resolve. While the first of these was a trivial fix, the second one is a little more involved. It was caused by attempting to build a query across tables that had no relationship as part of our archive logic. For example, consider the following queries, generated early in '_get_fk_stmts': SELECT instances.uuid FROM instances, security_group_instance_association WHERE security_group_instance_association.instance_uuid = instances.uuid AND instances.id IN (__[POSTCOMPILE_id_1]) SELECT security_groups.id FROM security_groups, security_group_instance_association, instances WHERE security_group_instance_association.security_group_id = security_groups.id AND instances.id IN (__[POSTCOMPILE_id_1]) While the first of these is fine, the second is clearly wrong: why are we filtering on a field that is of no relevance to our join? These were generated because we were attempting to archive one or more instances (in this case, the instance with id=1) and needed to find related tables to archive at the same time. A related table is any table that references our "source" table - 'instances' here - by way of a foreign key. For each of *these* tables, we then lookup each foreign key and join back to the source table, filtering by matching entries in the source table. The issue here is that we're looking up every foreign key. What we actually want to do is lookup only the foreign keys that point back to our source table. This flaw is why we were generating the second SELECT above: the 'security_group_instance_association' has two foreign keys, one pointing to our 'instances' table but also another pointing to the 'security_groups' table. We want the first but not the second. Resolve this by checking if the table that each foreign key points to is actually the source table and simply skip if not. With this issue resolved, we can enable errors on SAWarning warnings in general without any filters. Conflicts: nova/objects/cell_mapping.py nova/tests/fixtures/nova.py NOTE(melwitt): The conflicts are because * Change Ia5304c552ce552ae3c5223a2bfb3a9cd543ec57c (db: Post reshuffle cleanup) is not in Wallaby * The WarningsFixture is in nova/tests/fixtures.py in Wallaby and change I07be8e16381592fc177eeecd4f0d7f2db93eb09d (tests: Enable SADeprecationWarning warnings) is also not in Wallaby Change-Id: I63208c7bd5f9f4c3d5e4a40bd0f6253d0f042a37 Signed-off-by: Stephen Finucane (cherry picked from commit 8142b9dc47b7096ab9d8180f0b5b1e52d513e2dc) (cherry picked from commit ce2cc54bfe236554badb9f6bf53a958417e5525d) (cherry picked from commit 5b1d487d7fc49580a606b68e1271cae5f2f2df87) --- nova/db/sqlalchemy/api.py | 7 +++++++ nova/objects/cell_mapping.py | 12 ++++++++---- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py index db21e92eac1f..0e5efa9ca55a 100644 --- a/nova/db/sqlalchemy/api.py +++ b/nova/db/sqlalchemy/api.py @@ -4133,6 +4133,12 @@ def _get_fk_stmts(metadata, conn, table, column, records): fk_column = fk_table.c.id for fk in fk_table.foreign_keys: + if table != fk.column.table: + # if the foreign key doesn't actually point to the table we're + # archiving entries from then it's not relevant; trying to + # resolve this would result in a cartesian product + continue + # We need to find the records in the referring (child) table that # correspond to the records in our (parent) table so we can archive # them. @@ -4179,6 +4185,7 @@ def _get_fk_stmts(metadata, conn, table, column, records): # deque. fk_delete = fk_table.delete().where(fk_column.in_(fk_records)) deletes.appendleft(fk_delete) + # Repeat for any possible nested child tables. i, d = _get_fk_stmts(metadata, conn, fk_table, fk_column, fk_records) inserts.extendleft(i) diff --git a/nova/objects/cell_mapping.py b/nova/objects/cell_mapping.py index 63e3648d5fbf..f7fb27d1d1bb 100644 --- a/nova/objects/cell_mapping.py +++ b/nova/objects/cell_mapping.py @@ -279,11 +279,15 @@ class CellMappingList(base.ObjectListBase, base.NovaObject): # SELECT DISTINCT cell_id FROM instance_mappings \ # WHERE project_id = $project_id; cell_ids = context.session.query( - api_models.InstanceMapping.cell_id).filter_by( - project_id=project_id).distinct().subquery() + api_models.InstanceMapping.cell_id + ).filter_by( + project_id=project_id + ).distinct() # SELECT cell_mappings WHERE cell_id IN ($cell_ids); - return context.session.query(api_models.CellMapping).filter( - api_models.CellMapping.id.in_(cell_ids)).all() + return context.session.query( + api_models.CellMapping).filter( + api_models.CellMapping.id.in_(cell_ids) + ).all() @classmethod def get_by_project_id(cls, context, project_id):