1 files changed, 39 insertions, 0 deletions
diff --git a/lib/gitlab/analytics/cycle_analytics/median.rb b/lib/gitlab/analytics/cycle_analytics/median.rb
new file mode 100644
index 00000000000..41883a80338
--- /dev/null
+++ b/lib/gitlab/analytics/cycle_analytics/median.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module Analytics
+    module CycleAnalytics
+      class Median
+        include StageQueryHelpers
+
+        def initialize(stage:, query:)
+          @stage = stage
+          @query = query
+        end
+
+        def seconds
+          @query = @query.select(median_duration_in_seconds.as('median'))
+          result = execute_query(@query).first || {}
+
+          result['median'] ? result['median'].to_i : nil
+        end
+
+        private
+
+        attr_reader :stage
+
+        def percentile_cont
+          percentile_cont_ordering = Arel::Nodes::UnaryOperation.new(Arel::Nodes::SqlLiteral.new('ORDER BY'), duration)
+          Arel::Nodes::NamedFunction.new(
+            'percentile_cont(0.5) WITHIN GROUP',
+            [percentile_cont_ordering]
+          )
+        end
+
+        def median_duration_in_seconds
+          Arel::Nodes::Extract.new(percentile_cont, :epoch)
+        end
+      end
+    end
+  end
+end