Update the gitlab:db:reindex rake task

- Fix single-index invocation
- Add console logging

lib/tasks/gitlab/db.rake

@@ -192,12 +192,18 @@ namespace :gitlab do
         exit
       end
 
-      indexes = if args[:index_name]
-                  [Gitlab::Database::PostgresIndex.by_identifier(args[:index_name])]
-                else
-                  Gitlab::Database::Reindexing.candidate_indexes
+      indexes = Gitlab::Database::Reindexing.candidate_indexes
+
+      if identifier = args[:index_name]
+        raise ArgumentError, "Index name is not fully qualified with a schema: #{identifier}" unless identifier =~ /^\w+\.\w+$/
+
+        indexes = indexes.where(identifier: identifier)
+
+        raise "Index not found or not supported: #{args[:index_name]}" if indexes.empty?
       end
 
+      ActiveRecord::Base.logger = Logger.new(STDOUT) if Gitlab::Utils.to_boolean(ENV['LOG_QUERIES_TO_CONSOLE'], default: false)
+
       Gitlab::Database::Reindexing.perform(indexes)
     rescue => e
       Gitlab::AppLogger.error(e)

spec/tasks/gitlab/db_rake_spec.rb

@@ -246,17 +246,25 @@ RSpec.describe 'gitlab:db namespace rake task' do
     context 'with index name given' do
       let(:index) { double('index') }
 
+      before do
+        allow(Gitlab::Database::Reindexing).to receive(:candidate_indexes).and_return(indexes)
+      end
+
       it 'calls the index rebuilder with the proper arguments' do
-        expect(Gitlab::Database::PostgresIndex).to receive(:by_identifier).with('public.foo_idx').and_return(index)
+        allow(indexes).to receive(:where).with(identifier: 'public.foo_idx').and_return([index])
         expect(Gitlab::Database::Reindexing).to receive(:perform).with([index])
 
         run_rake_task('gitlab:db:reindex', '[public.foo_idx]')
       end
 
       it 'raises an error if the index does not exist' do
-        expect(Gitlab::Database::PostgresIndex).to receive(:by_identifier).with('public.absent_index').and_raise(ActiveRecord::RecordNotFound)
+        allow(indexes).to receive(:where).with(identifier: 'public.absent_index').and_return([])
+
+        expect { run_rake_task('gitlab:db:reindex', '[public.absent_index]') }.to raise_error(/Index not found/)
+      end
 
-        expect { run_rake_task('gitlab:db:reindex', '[public.absent_index]') }.to raise_error(ActiveRecord::RecordNotFound)
+      it 'raises an error if the index is not fully qualified with a schema' do
+        expect { run_rake_task('gitlab:db:reindex', '[foo_idx]') }.to raise_error(/Index name is not fully qualified/)
       end
     end
   end