Drastically improve project search performance by no longer searching namespace name

app/models/project.rb

@@ -18,6 +18,7 @@ class Project < ActiveRecord::Base
   include SelectForProjectAuthorization
   include Routable
   include GroupDescendant
+  include Gitlab::SQL::Pattern
 
   extend Gitlab::ConfigHelper
   extend Gitlab::CurrentSettings
@@ -424,32 +425,17 @@ class Project < ActiveRecord::Base
     #
     # query - The search query as a String.
     def search(query)
-      ptable  = arel_table
-      ntable  = Namespace.arel_table
-      pattern = "%#{query}%"
-
-      # unscoping unnecessary conditions that'll be applied
-      # when executing `where("projects.id IN (#{union.to_sql})")`
-      projects = unscoped.select(:id).where(
-        ptable[:path].matches(pattern)
-          .or(ptable[:name].matches(pattern))
-          .or(ptable[:description].matches(pattern))
-      )
-
-      namespaces = unscoped.select(:id)
-        .joins(:namespace)
-        .where(ntable[:name].matches(pattern))
-
-      union = Gitlab::SQL::Union.new([projects, namespaces])
+      pattern = to_pattern(query)
 
-      where("projects.id IN (#{union.to_sql})") # rubocop:disable GitlabSecurity/SqlInjection
+      where(
+        arel_table[:path].matches(pattern)
+          .or(arel_table[:name].matches(pattern))
+          .or(arel_table[:description].matches(pattern))
+      )
     end
 
     def search_by_title(query)
-      pattern = "%#{query}%"
-      table   = Project.arel_table
-
-      non_archived.where(table[:name].matches(pattern))
+      non_archived.where(arel_table[:name].matches(to_pattern(query)))
     end
 
     def visibility_levels

changelogs/unreleased/dm-project-search-performance.yml

+---
+title: Drastically improve project search performance by no longer searching namespace
+  name
+merge_request:
+author:
+type: performance

lib/gitlab/search_results.rb

@@ -30,7 +30,7 @@ module Gitlab
     def initialize(current_user, limit_projects, query)
       @current_user = current_user
       @limit_projects = limit_projects || Project.all
-      @query = Shellwords.shellescape(query) if query.present?
+      @query = query
     end
 
     def objects(scope, page = nil)

spec/finders/admin/projects_finder_spec.rb

@@ -136,7 +136,7 @@ describe Admin::ProjectsFinder do
     context 'filter by name' do
       let(:params) { { name: 'C' } }
 
-      it { is_expected.to match_array([shared_project, public_project, private_project]) }
+      it { is_expected.to match_array([public_project]) }
     end
 
     context 'sorting' do

spec/models/project_spec.rb

@@ -1254,24 +1254,6 @@ describe Project do
       expect(described_class.search(project.path.upcase)).to eq([project])
     end
 
-    it 'returns projects with a matching namespace name' do
-      expect(described_class.search(project.namespace.name)).to eq([project])
-    end
-
-    it 'returns projects with a partially matching namespace name' do
-      expect(described_class.search(project.namespace.name[0..2])).to eq([project])
-    end
-
-    it 'returns projects with a matching namespace name regardless of the casing' do
-      expect(described_class.search(project.namespace.name.upcase)).to eq([project])
-    end
-
-    it 'returns projects when eager loading namespaces' do
-      relation = described_class.all.includes(:namespace)
-
-      expect(relation.search(project.namespace.name)).to eq([project])
-    end
-
     describe 'with pending_delete project' do
       let(:pending_delete_project) { create(:project, pending_delete: true) }
 

spec/services/search/global_service_spec.rb

@@ -35,8 +35,8 @@ describe Search::GlobalService do
         expect(results.objects('projects')).to match_array [internal_project, public_project]
       end
 
-      it 'namespace name is searchable' do
-        results = described_class.new(user, search: found_project.namespace.path).execute
+      it 'project name is searchable' do
+        results = described_class.new(user, search: found_project.name).execute
 
         expect(results.objects('projects')).to match_array [found_project]
       end