From ac702af8229193834baf8d3fd3a1b454b5459289 Mon Sep 17 00:00:00 2001 From: Yorick Peterse Date: Fri, 15 Sep 2017 15:34:41 +0200 Subject: Fix setting share_with_group_lock Prior to this commit running Namespace#force_share_with_group_lock_on_descendants would result in updating _all_ namespaces in the namespaces table, not just the descendants. This is the result of ActiveRecord::Relation#update_all not taking into account the CTE. To work around this we use the CTE query as a sub-query instead of directly calling #update_all. To prevent this from happening the relations returned by Gitlab::GroupHierarchy are now marked as read-only, resulting in an error being raised when methods such as #update_all are used. Fortunately on GitLab.com our statement timeouts appear to have prevented this query from actually doing any damage other than causing a very large amount of dead tuples. Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/37916 --- app/models/namespace.rb | 9 ++++++++- lib/gitlab/database/read_only_relation.rb | 16 ++++++++++++++++ lib/gitlab/group_hierarchy.rb | 15 ++++++++++++--- spec/lib/gitlab/group_hierarchy_spec.rb | 15 +++++++++++++++ 4 files changed, 51 insertions(+), 4 deletions(-) create mode 100644 lib/gitlab/database/read_only_relation.rb diff --git a/app/models/namespace.rb b/app/models/namespace.rb index 4a9a23fea1f..e279d8dd8c5 100644 --- a/app/models/namespace.rb +++ b/app/models/namespace.rb @@ -231,6 +231,13 @@ class Namespace < ActiveRecord::Base end def force_share_with_group_lock_on_descendants - descendants.update_all(share_with_group_lock: true) + return unless Group.supports_nested_groups? + + # We can't use `descendants.update_all` since Rails will throw away the WITH + # RECURSIVE statement. We also can't use WHERE EXISTS since we can't use + # different table aliases, hence we're just using WHERE IN. Since we have a + # maximum of 20 nested groups this should be fine. + Namespace.where(id: descendants.select(:id)) + .update_all(share_with_group_lock: true) end end diff --git a/lib/gitlab/database/read_only_relation.rb b/lib/gitlab/database/read_only_relation.rb new file mode 100644 index 00000000000..4571ad122ce --- /dev/null +++ b/lib/gitlab/database/read_only_relation.rb @@ -0,0 +1,16 @@ +module Gitlab + module Database + # Module that can be injected into a ActiveRecord::Relation to make it + # read-only. + module ReadOnlyRelation + [:delete, :delete_all, :update, :update_all].each do |method| + define_method(method) do |*args| + raise( + ActiveRecord::ReadOnlyRecord, + "This relation is marked as read-only" + ) + end + end + end + end +end diff --git a/lib/gitlab/group_hierarchy.rb b/lib/gitlab/group_hierarchy.rb index 5a31e56cb30..635f52131f9 100644 --- a/lib/gitlab/group_hierarchy.rb +++ b/lib/gitlab/group_hierarchy.rb @@ -22,7 +22,7 @@ module Gitlab def base_and_ancestors return ancestors_base unless Group.supports_nested_groups? - base_and_ancestors_cte.apply_to(model.all) + read_only(base_and_ancestors_cte.apply_to(model.all)) end # Returns a relation that includes the descendants_base set of groups @@ -30,7 +30,7 @@ module Gitlab def base_and_descendants return descendants_base unless Group.supports_nested_groups? - base_and_descendants_cte.apply_to(model.all) + read_only(base_and_descendants_cte.apply_to(model.all)) end # Returns a relation that includes the base groups, their ancestors, @@ -67,11 +67,13 @@ module Gitlab union = SQL::Union.new([model.unscoped.from(ancestors_table), model.unscoped.from(descendants_table)]) - model + relation = model .unscoped .with .recursive(ancestors.to_arel, descendants.to_arel) .from("(#{union.to_sql}) #{model.table_name}") + + read_only(relation) end private @@ -107,5 +109,12 @@ module Gitlab def groups_table model.arel_table end + + def read_only(relation) + # relations using a CTE are not safe to use with update_all as it will + # throw away the CTE, hence we mark them as read-only. + relation.extend(Gitlab::Database::ReadOnlyRelation) + relation + end end end diff --git a/spec/lib/gitlab/group_hierarchy_spec.rb b/spec/lib/gitlab/group_hierarchy_spec.rb index 08010c2d0e2..8dc83a6db7f 100644 --- a/spec/lib/gitlab/group_hierarchy_spec.rb +++ b/spec/lib/gitlab/group_hierarchy_spec.rb @@ -23,6 +23,11 @@ describe Gitlab::GroupHierarchy, :postgresql do expect(relation).to include(parent, child1, child2) end + + it 'does not allow the use of #update_all' do + expect { relation.update_all(share_with_group_lock: false) } + .to raise_error(ActiveRecord::ReadOnlyRecord) + end end describe '#base_and_descendants' do @@ -43,6 +48,11 @@ describe Gitlab::GroupHierarchy, :postgresql do expect(relation).to include(parent, child1, child2) end + + it 'does not allow the use of #update_all' do + expect { relation.update_all(share_with_group_lock: false) } + .to raise_error(ActiveRecord::ReadOnlyRecord) + end end describe '#all_groups' do @@ -73,5 +83,10 @@ describe Gitlab::GroupHierarchy, :postgresql do expect(relation).to include(child2) end + + it 'does not allow the use of #update_all' do + expect { relation.update_all(share_with_group_lock: false) } + .to raise_error(ActiveRecord::ReadOnlyRecord) + end end end -- cgit v1.2.1