Stop eager loading dependencies in dependency parsing workers

The includes(manifests: :dependencies) call loads all dependency rows
into memory but parse_dependencies never reads them. Keep the manifests
eager load since sync_manifest and delete_old_manifests use the loaded
collection, but drop the nested :dependencies to avoid loading
potentially millions of rows.

Author: andrew

app/sidekiq/parse_dependencies_worker.rb

@@ -3,6 +3,6 @@ class ParseDependenciesWorker
   sidekiq_options queue: 'dependencies', lock: :until_executed, lock_expiration: 1.day.to_i
 
   def perform(repository_id)
-    Repository.find_by_id(repository_id).try(:parse_dependencies)
+    Repository.includes(:manifests).find_by_id(repository_id).try(:parse_dependencies)
   end
 end

app/sidekiq/parse_tag_dependencies_worker.rb

@@ -3,6 +3,6 @@ class ParseTagDependenciesWorker
   sidekiq_options queue: 'dependencies', lock: :until_executed, lock_expiration: 1.day.to_i
 
   def perform(tag_id)
-    Tag.find_by_id(tag_id).try(:parse_dependencies)
+    Tag.includes(:manifests).find_by_id(tag_id).try(:parse_dependencies)
   end
 end

test/workers/parse_dependencies_worker_test.rb

@@ -20,7 +20,7 @@ class ParseDependenciesWorkerTest < ActiveSupport::TestCase
       end
     end
 
-    should 'not eager load manifests and dependencies' do
+    should 'eager load manifests but not dependencies' do
       host = create(:host)
       repository = create(:repository, host: host)
       manifest = create(:manifest, repository: repository)
@@ -37,8 +37,10 @@ class ParseDependenciesWorkerTest < ActiveSupport::TestCase
         ParseDependenciesWorker.new.perform(repository.id)
       end
 
-      eager_load_queries = queries.select { |q| q.include?('manifests') || q.include?('dependencies') }
-      assert_empty eager_load_queries, "Should not eager load manifests or dependencies"
+      manifest_queries = queries.select { |q| q.include?('manifests') }
+      dependency_queries = queries.select { |q| q.include?('dependencies') }
+      assert manifest_queries.any?, "Should eager load manifests"
+      assert_empty dependency_queries, "Should not eager load dependencies"
     end
   end
 end

test/workers/parse_tag_dependencies_worker_test.rb

@@ -21,7 +21,7 @@ class ParseTagDependenciesWorkerTest < ActiveSupport::TestCase
       end
     end
 
-    should 'not eager load manifests and dependencies' do
+    should 'eager load manifests but not dependencies' do
       host = create(:host)
       repository = create(:repository, host: host)
       tag = create(:tag, repository: repository)
@@ -38,8 +38,10 @@ class ParseTagDependenciesWorkerTest < ActiveSupport::TestCase
         ParseTagDependenciesWorker.new.perform(tag.id)
       end
 
-      eager_load_queries = queries.select { |q| q.include?('manifests') || q.include?('dependencies') }
-      assert_empty eager_load_queries, "Should not eager load manifests or dependencies"
+      manifest_queries = queries.select { |q| q.include?('manifests') }
+      dependency_queries = queries.select { |q| q.include?('dependencies') }
+      assert manifest_queries.any?, "Should eager load manifests"
+      assert_empty dependency_queries, "Should not eager load dependencies"
     end
   end
 end