Delete conflicting redirects in background

1 files changed, 66 insertions, 0 deletions

diff --git a/db/post_migrate/20170907170235_delete_conflicting_redirect_routes.rb b/db/post_migrate/20170907170235_delete_conflicting_redirect_routes.rb
new file mode 100644
index 00000000000..4111c884c28
--- /dev/null
+++ b/db/post_migrate/20170907170235_delete_conflicting_redirect_routes.rb
@@ -0,0 +1,66 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class DeleteConflictingRedirectRoutes < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  BATCH_SIZE = 1000 # Number of rows to process per job
+  JOB_BUFFER_SIZE = 1000 # Number of jobs to bulk queue at a time
+  MIGRATION = 'DeleteConflictingRedirectRoutes'.freeze
+
+  disable_ddl_transaction!
+
+  class Route < ActiveRecord::Base
+    include EachBatch
+
+    self.table_name = 'routes'
+  end
+
+  def up
+    jobs = []
+
+    say opening_message
+
+    queue_background_migration_jobs(Route, MIGRATION)
+  end
+
+  def down
+    # nothing
+  end
+
+  def opening_message
+    <<~MSG
+      Clean up redirect routes that conflict with regular routes.
+         See initial bug fix:
+         https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13357
+    MSG
+  end
+
+  def queue_background_migration_jobs(model_class, job_class_name, batch_size = BATCH_SIZE)
+    jobs = []
+
+    model_class.each_batch(of: batch_size) do |relation|
+      start_id, end_id = relation.pluck('MIN(id), MAX(id)').first
+
+      # Note: This conditional will only be true if JOB_BUFFER_SIZE * batch_size < (total number of rows)
+      if jobs.length >= JOB_BUFFER_SIZE
+        # We push multiple jobs at a time to reduce the time spent in
+        # Sidekiq/Redis operations. We're using this buffer based approach so we
+        # don't need to run additional queries for every range.
+        bulk_queue_jobs(jobs)
+        jobs.clear
+      end
+
+      jobs << [job_class_name, [start_id, end_id]]
+    end
+
+    bulk_queue_jobs(jobs) unless jobs.empty?
+  end
+
+  def bulk_queue_jobs(jobs)
+    say "Queuing #{jobs.size} BackgroundMigrationWorker jobs..."
+
+    BackgroundMigrationWorker.perform_bulk(jobs)
+  end
+end