B OpenNebula#3269: onedb purge-done eat too much RAM

    * Divide the function between delete VMs and history records
    * Delete in group of 1000 VMs

src/onedb/onedb_live.rb

@@ -205,6 +205,27 @@ def purge_history(options = {})
         end
     end
 
+    def purge_object(object, id, last_id, pool, start_time, end_time)
+        count = 0
+
+        pool.each do |obj|
+            if count % 1000 == 0 && count > 0
+                sleep(10)
+                count = 0
+            end
+
+            print percentage_line(obj.id, last_id, true)
+
+            time = obj["ETIME"].to_i
+
+            next unless time >= start_time && time < end_time
+
+            delete(object, "#{id} = #{obj.id}", false)
+
+            count += 1
+        end
+    end
+
     def purge_done_vm(options = {})
         vmpool = OpenNebula::VirtualMachinePool.new(client)
         vmpool.info(OpenNebula::Pool::INFO_ALL,
@@ -219,18 +240,15 @@ def purge_done_vm(options = {})
 
         start_time  = ops[:start_time].to_i
         end_time    = ops[:end_time].to_i
+        last_id     = vmpool["/VM_POOL/VM[last()]/ID"]
 
-        last_id = vmpool["/VM_POOL/VM[last()]/ID"]
+        puts "Deleting VMs from VM_POOL"
 
-        vmpool.each do |vm|
-            print percentage_line(vm.id, last_id, true)
+        purge_object('vm_pool', 'oid', last_id, vmpool, start_time, end_time)
 
-            time = vm["ETIME"].to_i
-            next unless time >= start_time && time < end_time
+        puts "Deleting history records"
 
-            delete("vm_pool", "oid = #{vm.id}", false)
-            delete("history", "vid = #{vm.id}", false)
-        end
+        purge_object('history', 'vid', last_id, vmpool, start_time, end_time)
     end
 
     def check_expr(object, expr)