Retry migration removing stages in case of duplicates

1 files changed, 17 insertions, 4 deletions

diff --git a/db/post_migrate/20180119121225_remove_redundant_pipeline_stages.rb b/db/post_migrate/20180119121225_remove_redundant_pipeline_stages.rb
index be5a80261c0..9644cfabb60 100644
--- a/db/post_migrate/20180119121225_remove_redundant_pipeline_stages.rb
+++ b/db/post_migrate/20180119121225_remove_redundant_pipeline_stages.rb
@@ -3,12 +3,15 @@ class RemoveRedundantPipelineStages < ActiveRecord::Migration
 
   DOWNTIME = false
 
-  def up
-    remove_concurrent_index :ci_stages, [:pipeline_id, :name]
+  disable_ddl_transaction!
 
+  def up(attempts: 100)
+    remove_outdated_index!
     remove_redundant_pipeline_stages!
-
-    add_concurrent_index :ci_stages, [:pipeline_id, :name], unique: true
+    add_unique_index!
+  rescue ActiveRecord::RecordNotUnique
+    retry if (attempts -= 1) > 0
+    raise
   end
 
   def down
@@ -18,6 +21,16 @@ class RemoveRedundantPipelineStages < ActiveRecord::Migration
 
   private
 
+  def remove_outdated_index!
+    return unless index_exists?(:ci_stages, [:pipeline_id, :name])
+
+    remove_concurrent_index :ci_stages, [:pipeline_id, :name]
+  end
+
+  def add_unique_index!
+    add_concurrent_index :ci_stages, [:pipeline_id, :name], unique: true
+  end
+
   def remove_redundant_pipeline_stages!
     redundant_stages_ids = <<~SQL
       SELECT id FROM ci_stages WHERE (pipeline_id, name) IN (