task.rb in pgsync-0.6.2

- old
+ new

@@ -273,19 +273,29 @@
       raise Error, "Single column primary key required for this data rule: #{rule}" unless primary_key.size == 1
       "#{quoted_table}.#{quote_ident(primary_key.first)}"
     end
 
     def maybe_disable_triggers
-      if opts[:disable_integrity] || opts[:disable_user_triggers]
+      if opts[:disable_integrity] || opts[:disable_integrity_v2] || opts[:disable_user_triggers]
         destination.transaction do
           triggers = destination.triggers(table)
           triggers.select! { |t| t["enabled"] == "t" }
           internal_triggers, user_triggers = triggers.partition { |t| t["internal"] == "t" }
           integrity_triggers = internal_triggers.select { |t| t["integrity"] == "t" }
           restore_triggers = []
 
-          if opts[:disable_integrity]
+          # both --disable-integrity options require superuser privileges
+          # however, only v2 works on Amazon RDS, which added specific support for it
+          # https://aws.amazon.com/about-aws/whats-new/2014/11/10/amazon-rds-postgresql-read-replicas/
+          #
+          # session_replication_role disables more than foreign keys (like triggers and rules)
+          # this is probably fine, but keep the current default for now
+          if opts[:disable_integrity_v2] || (opts[:disable_integrity] && rds?)
+            # SET LOCAL lasts until the end of the transaction
+            # https://www.postgresql.org/docs/current/sql-set.html
+            destination.execute("SET LOCAL session_replication_role = replica")
+          elsif opts[:disable_integrity]
             integrity_triggers.each do |trigger|
               destination.execute("ALTER TABLE #{quoted_table} DISABLE TRIGGER #{quote_ident(trigger["name"])}")
             end
             restore_triggers.concat(integrity_triggers)
           end
@@ -308,8 +318,12 @@
           result
         end
       else
         yield
       end
+    end
+
+    def rds?
+      destination.execute("SELECT name, setting FROM pg_settings WHERE name LIKE 'rds.%'").any?
     end
   end
 end