Migration to remove pending delete projects with non-existing namespace

There might be some projects where the namespace was removed, but the
project wasn't. For these the projects still have a `namespace_id`
set. So this adds a post-deploy migration remove all projects that are
pending delete, and have a `namespace_id` that is non-existing.

1 files changed, 54 insertions, 0 deletions

diff --git a/db/post_migrate/20170816102555_cleanup_nonexisting_namespace_pending_delete_projects.rb b/db/post_migrate/20170816102555_cleanup_nonexisting_namespace_pending_delete_projects.rb
new file mode 100644
index 00000000000..fe88f25827f
--- /dev/null
+++ b/db/post_migrate/20170816102555_cleanup_nonexisting_namespace_pending_delete_projects.rb
@@ -0,0 +1,54 @@
+# Follow up of CleanupNamespacelessPendingDeleteProjects and it cleans
+# all projects with `pending_delete = true` and for which the
+# namespace no longer exists.
+class CleanupNonexistingNamespacePendingDeleteProjects < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    @offset = 0
+
+    loop do
+      ids = pending_delete_batch
+
+      break if ids.empty?
+
+      args = ids.map { |id| Array(id) }
+
+      NamespacelessProjectDestroyWorker.bulk_perform_async(args)
+
+      @offset += 1
+    end
+  end
+
+  def down
+    # noop
+  end
+
+  private
+
+  def pending_delete_batch
+    connection.exec_query(find_batch).map { |row| row['id'].to_i }
+  end
+
+  BATCH_SIZE = 5000
+
+  def find_batch
+    projects = Project.arel_table
+    namespaces = Namespace.arel_table
+
+    namespace_query = namespaces.project(1)
+                        .where(namespaces[:id].eq(projects[:namespace_id]))
+                        .exists.not
+
+    projects.project(projects[:id])
+      .where(projects[:pending_delete].eq(true))
+      .where(namespace_query)
+      .skip(@offset * BATCH_SIZE)
+      .take(BATCH_SIZE)
+      .to_sql
+  end
+end