Optimize the ES Query for confidentiality check

Previously, we would do separate checks for project membership and
confidentiality checks.

This commit adds an optimization that will limit the confidentiality
check to be within the limited projects, if such a limit exists.

ee/changelogs/unreleased/225998-advanced-search-result-page-is-slow.yml

+---
+title: Optimize the Advanced Search query for Issues and Notes.
+merge_request: 38095
+author:
+type: performance

ee/lib/elastic/latest/application_class_proxy.rb

@@ -171,7 +171,7 @@ module Elastic
           limit =
             { terms: { "#{feature}_access_level" => [::ProjectFeature::ENABLED, ::ProjectFeature::PRIVATE] } }
 
-          { bool: { filter: [condition, limit].compact } }
+          { bool: { filter: [condition, limit] } }
         end
       end
 
@@ -226,11 +226,24 @@ module Elastic
         # When reading cross project is not allowed, only allow searching a
         # a single project, so the `:read_*` ability is only checked once.
         unless Ability.allowed?(current_user, :read_cross_project)
-          project_ids = [] if project_ids.size > 1
+          return [] if project_ids.size > 1
         end
 
         project_ids
       end
+
+      def authorized_project_ids(current_user, options = {})
+        return [] unless current_user
+
+        scoped_project_ids = scoped_project_ids(current_user, options[:project_ids])
+        authorized_project_ids = current_user.authorized_projects(Gitlab::Access::REPORTER).pluck_primary_key.to_set
+
+        # if the current search is limited to a subset of projects, we should do
+        # confidentiality check for these projects.
+        authorized_project_ids &= scoped_project_ids.to_set unless scoped_project_ids == :any
+
+        authorized_project_ids.to_a
+      end
     end
   end
 end

ee/lib/elastic/latest/issue_class_proxy.rb

@@ -13,29 +13,32 @@ module Elastic
 
         options[:features] = 'issues'
         query_hash = project_ids_filter(query_hash, options)
-        query_hash = confidentiality_filter(query_hash, options[:current_user], options[:project_ids])
+        query_hash = confidentiality_filter(query_hash, options)
 
         search(query_hash, options)
       end
 
       private
 
-      def user_has_access_to_confidential_issues?(authorized_project_ids, project_ids)
-        # is_a?(Array) is needed because we might receive project_ids: :any
-        return false unless authorized_project_ids && project_ids.is_a?(Array)
+      def confidentiality_filter(query_hash, options)
+        current_user = options[:current_user]
+        project_ids = options[:project_ids]
 
-        (project_ids - authorized_project_ids).empty?
-      end
-
-      def confidentiality_filter(query_hash, current_user, project_ids)
         return query_hash if current_user&.can_read_all_resources?
 
-        authorized_project_ids = current_user&.authorized_projects(Gitlab::Access::REPORTER)&.pluck_primary_key
-        return query_hash if user_has_access_to_confidential_issues?(authorized_project_ids, project_ids)
+        scoped_project_ids = scoped_project_ids(current_user, project_ids)
+        authorized_project_ids = authorized_project_ids(current_user, options)
+
+        # we can shortcut the filter if the user is authorized to see
+        # all the projects for which this query is scoped on
+        unless scoped_project_ids == :any || scoped_project_ids.empty?
+          return query_hash if authorized_project_ids.to_set == scoped_project_ids.to_set
+        end
+
+        filter = { term: { confidential: false } }
 
-        filter =
         if current_user
-            {
+          filter = {
               bool: {
                 should: [
                   { term: { confidential: false } },
@@ -58,8 +61,6 @@ module Elastic
                 ]
               }
             }
-          else
-            { term: { confidential: false } }
         end
 
         query_hash[:query][:bool][:filter] << filter

ee/lib/elastic/latest/note_class_proxy.rb

@@ -14,7 +14,7 @@ module Elastic
 
         query_hash = basic_query_hash(%w[note], query)
         query_hash = project_ids_filter(query_hash, options)
-        query_hash = confidentiality_filter(query_hash, options[:current_user])
+        query_hash = confidentiality_filter(query_hash, options)
 
         query_hash[:highlight] = highlight_options(options[:in])
 
@@ -23,7 +23,9 @@ module Elastic
 
       private
 
-      def confidentiality_filter(query_hash, current_user)
+      def confidentiality_filter(query_hash, options)
+        current_user = options[:current_user]
+
         return query_hash if current_user&.can_read_all_resources?
 
         filter = {
@@ -43,7 +45,7 @@ module Elastic
                     bool: {
                     should: [
                       { bool: { must_not: [{ exists: { field: :confidential } }] } },
-                      { term: { "confidential" => false } }
+                      { term: { confidential: false } }
                     ]
                     }
                   }
@@ -61,7 +63,7 @@ module Elastic
                   bool: {
                     should: [
                       { term: { "issue.confidential" => true } },
-                      { term: { "confidential" => true } }
+                      { term: { confidential: true } }
                     ]
                   }
                 },
@@ -70,7 +72,7 @@ module Elastic
                     should: [
                       { term: { "issue.author_id" => current_user.id } },
                       { term: { "issue.assignee_id" => current_user.id } },
-                      { terms: { "project_id" => current_user.authorized_projects(Gitlab::Access::REPORTER).pluck_primary_key } }
+                      { terms: { project_id: authorized_project_ids(current_user, options) } }
                     ]
                   }
                 }

spec/spec_helper.rb

@@ -261,6 +261,7 @@ RSpec.configure do |config|
       ./spec/support/protected_tags
       ./spec/support/shared_examples/features
       ./spec/support/shared_examples/requests
+      ./spec/support/shared_examples/lib/gitlab
       ./spec/views
       ./spec/workers
     )

spec/support/shared_examples/lib/gitlab/project_search_results_shared_examples.rb

@@ -10,10 +10,6 @@ RSpec.shared_examples 'access restricted confidential issues' do
   let!(:security_issue_1) { create(:issue, :confidential, project: project, title: 'Security issue 1', author: author) }
   let!(:security_issue_2) { create(:issue, :confidential, title: 'Security issue 2', project: project, assignees: [assignee]) }
 
-  before do
-    stub_feature_flags(user_mode_in_session: false)
-  end
-
   subject(:objects) do
     described_class.new(user, query, project: project).objects('issues')
   end