Remove redundant pipeline stages from the database

2 files changed, 27 insertions, 1 deletions

diff --git a/db/post_migrate/20180119121225_remove_redundant_pipeline_stages.rb b/db/post_migrate/20180119121225_remove_redundant_pipeline_stages.rb
new file mode 100644
index 00000000000..3868e0adae1
--- /dev/null
+++ b/db/post_migrate/20180119121225_remove_redundant_pipeline_stages.rb
@@ -0,0 +1,26 @@
+class RemoveRedundantPipelineStages < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def up
+   redundant_stages_ids = <<~SQL
+      SELECT id FROM ci_stages a WHERE (
+        SELECT COUNT(*) FROM ci_stages b
+          WHERE a.pipeline_id = b.pipeline_id AND a.name = b.name
+      ) > 1
+    SQL
+
+    execute <<~SQL
+      UPDATE ci_builds SET stage_id = NULL WHERE ci_builds.stage_id IN (#{redundant_stages_ids})
+    SQL
+
+    execute <<~SQL
+      DELETE FROM ci_stages WHERE ci_stages.id IN (#{redundant_stages_ids})
+    SQL
+  end
+
+  def down
+    # noop
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index a0901833c3d..9becd794553 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180113220114) do
+ActiveRecord::Schema.define(version: 20180119121225) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"