Revamp finding projects by namespaces

By using a JOIN we can remove the need for using 2 separate queries to
find a project by its namespace. Combined with an index (only needed for
PostgreSQL) this reduces the query time from ~245 ms (~520 ms for the
first call) down to roughly 10 ms (~15 ms for the first call).

1 files changed, 20 insertions, 0 deletions

diff --git a/spec/benchmarks/models/project_spec.rb b/spec/benchmarks/models/project_spec.rb
new file mode 100644
index 00000000000..0c6b533ac2b
--- /dev/null
+++ b/spec/benchmarks/models/project_spec.rb
@@ -0,0 +1,20 @@
+require 'spec_helper'
+
+describe Project, benchmark: true do
+  describe '.find_with_namespace' do
+    let(:group)   { create(:group, name: 'sisinmaru') }
+    let(:project) { create(:project, name: 'maru', namespace: group) }
+
+    describe 'using a capitalized namespace' do
+      benchmark_subject { described_class.find_with_namespace('sisinmaru/MARU') }
+
+      it { is_expected.to iterate_per_second(600) }
+    end
+
+    describe 'using a lowercased namespace' do
+      benchmark_subject { described_class.find_with_namespace('sisinmaru/maru') }
+
+      it { is_expected.to iterate_per_second(600) }
+    end
+  end
+end