95 lines
3.1 KiB
Ruby
95 lines
3.1 KiB
Ruby
# frozen_string_literal: true
|
|
#
|
|
# Query a recursively defined namespace hierarchy using linear methods through
|
|
# the traversal_ids attribute.
|
|
#
|
|
# Namespace is a nested hierarchy of one parent to many children. A search
|
|
# using only the parent-child relationships is a slow operation. This process
|
|
# was previously optimized using Postgresql recursive common table expressions
|
|
# (CTE) with acceptable performance. However, it lead to slower than possible
|
|
# performance, and resulted in complicated queries that were difficult to make
|
|
# performant.
|
|
#
|
|
# Instead of searching the hierarchy recursively, we store a `traversal_ids`
|
|
# attribute on each node. The `traversal_ids` is an ordered array of Namespace
|
|
# IDs that define the traversal path from the root Namespace to the current
|
|
# Namespace.
|
|
#
|
|
# For example, suppose we have the following Namespaces:
|
|
#
|
|
# GitLab (id: 1) > Engineering (id: 2) > Manage (id: 3) > Access (id: 4)
|
|
#
|
|
# Then `traversal_ids` for group "Access" is [1, 2, 3, 4]
|
|
#
|
|
# And we can match against other Namespace `traversal_ids` such that:
|
|
#
|
|
# - Ancestors are [1], [1, 2], [1, 2, 3]
|
|
# - Descendants are [1, 2, 3, 4, *]
|
|
# - Root is [1]
|
|
# - Hierarchy is [1, *]
|
|
#
|
|
# Note that this search method works so long as the IDs are unique and the
|
|
# traversal path is ordered from root to leaf nodes.
|
|
#
|
|
# We implement this in the database using Postgresql arrays, indexed by a
|
|
# generalized inverted index (gin).
|
|
module Namespaces
|
|
module Traversal
|
|
module Linear
|
|
extend ActiveSupport::Concern
|
|
|
|
UnboundedSearch = Class.new(StandardError)
|
|
|
|
included do
|
|
after_create :sync_traversal_ids, if: -> { sync_traversal_ids? }
|
|
after_update :sync_traversal_ids, if: -> { sync_traversal_ids? && saved_change_to_parent_id? }
|
|
|
|
scope :traversal_ids_contains, ->(ids) { where("traversal_ids @> (?)", ids) }
|
|
end
|
|
|
|
def sync_traversal_ids?
|
|
Feature.enabled?(:sync_traversal_ids, root_ancestor, default_enabled: :yaml)
|
|
end
|
|
|
|
def use_traversal_ids?
|
|
return false unless Feature.enabled?(:use_traversal_ids, root_ancestor, default_enabled: :yaml)
|
|
|
|
traversal_ids.present?
|
|
end
|
|
|
|
def self_and_descendants
|
|
if use_traversal_ids?
|
|
lineage(self)
|
|
else
|
|
super
|
|
end
|
|
end
|
|
|
|
private
|
|
|
|
# Update the traversal_ids for the full hierarchy.
|
|
#
|
|
# NOTE: self.traversal_ids will be stale. Reload for a fresh record.
|
|
def sync_traversal_ids
|
|
# Clear any previously memoized root_ancestor as our ancestors have changed.
|
|
clear_memoization(:root_ancestor)
|
|
|
|
Namespace::TraversalHierarchy.for_namespace(root_ancestor).sync_traversal_ids!
|
|
end
|
|
|
|
# Make sure we drop the STI `type = 'Group'` condition for better performance.
|
|
# Logically equivalent so long as hierarchies remain homogeneous.
|
|
def without_sti_condition
|
|
self.class.unscope(where: :type)
|
|
end
|
|
|
|
# Search this namespace's lineage. Bound inclusively by top node.
|
|
def lineage(top)
|
|
raise UnboundedSearch.new('Must bound search by a top') unless top
|
|
|
|
without_sti_condition
|
|
.traversal_ids_contains("{#{top.id}}")
|
|
end
|
|
end
|
|
end
|
|
end
|