Fix project records with invalid visibility_level values

changelogs/unreleased/22699-group-permssion-background-migration.yml

+---
+title: Fix project records with invalid visibility_level values
+merge_request: 7391
+author: 

db/post_migrate/20161109150329_fix_project_records_with_invalid_visibility.rb

+class FixProjectRecordsWithInvalidVisibility < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  BATCH_SIZE = 1000
+  DOWNTIME = false
+
+  # This migration is idempotent and there's no sense in throwing away the
+  # partial result if it's interrupted
+  disable_ddl_transaction!
+
+  def up
+    projects = Arel::Table.new(:projects)
+    namespaces = Arel::Table.new(:namespaces)
+
+    finder =
+      projects.
+      join(namespaces, Arel::Nodes::InnerJoin).
+      on(projects[:namespace_id].eq(namespaces[:id])).
+      where(projects[:visibility_level].gt(namespaces[:visibility_level])).
+      project(projects[:id]).
+      take(BATCH_SIZE)
+
+    # MySQL requires a derived table to perform this query
+    nested_finder =
+      projects.
+      from(finder.as("AS projects_inner")).
+      project(projects[:id])
+
+    valuer =
+      namespaces.
+      where(namespaces[:id].eq(projects[:namespace_id])).
+      project(namespaces[:visibility_level])
+
+    # Update matching rows until none remain. The finder contains a limit.
+    loop do
+      updater = Arel::UpdateManager.new(ActiveRecord::Base).
+        table(projects).
+        set(projects[:visibility_level] => Arel::Nodes::SqlLiteral.new("(#{valuer.to_sql})")).
+        where(projects[:id].in(nested_finder))
+
+      num_updated = connection.exec_update(updater.to_sql, self.class.name, [])
+      break if num_updated == 0
+    end
+  end
+
+  def down
+    # no-op
+  end
+end

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: 20161106185620) do
+ActiveRecord::Schema.define(version: 20161109150329) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"