Merge branch 'backup_restore_drop_sequences' into 'master'

Drop all Postgres sequences during backup restore

See merge request !1226

CHANGELOG

@@ -3,6 +3,7 @@ v 7.5.0
   - Add time zone configuration on gitlab.yml (Sullivan Senechal)
   - Fix LDAP authentication for Git HTTP access
   - Fix LDAP config lookup for provider 'ldap'
+  - Drop all sequences during Postgres database restore
   - Project title links to project homepage (Ben Bodenmiller)
   - Add Atlassian Bamboo CI service (Drew Blessing)
   - Mentioned @user will receive email even if he is not participating in issue or commit

lib/backup/database.rb

@@ -34,6 +34,7 @@ module Backup
         # Drop all tables because PostgreSQL DB dumps do not contain DROP TABLE
         # statements like MySQL.
         Rake::Task["gitlab:db:drop_all_tables"].invoke
+        Rake::Task["gitlab:db:drop_all_postgres_sequences"].invoke
         pg_env
         system('psql', config['database'], '-f', db_file_name)
       end

lib/tasks/gitlab/db/drop_all_postgres_sequences.rake

+namespace :gitlab do
+  namespace :db do
+    task drop_all_postgres_sequences: :environment do
+      connection = ActiveRecord::Base.connection
+      connection.execute("SELECT c.relname FROM pg_class c WHERE c.relkind = 'S';").each do |sequence|
+        connection.execute("DROP SEQUENCE #{sequence['relname']}")
+      end
+    end
+  end
+end