My co-workers and I have been using Drools to great success, but we ran smack into a performance brick wall recently.

In the example below, both BINNING_INPUT and LU_DEVICE_TYPE have large numbers of associated facts in working memory (BINNING_INPUT has more than 8 million facts in working memory, LU_DEVICE_TYPE about 10k.)

LU_DEVICE_TYPE models a lookup table.

rule "Binning for Attribute: Device_type_desc"
  when
    $call :
      BINNING_INPUT()
    $device_typeLookup :
      LU_DEVICE_TYPE(
        $call.device_type == device_type
      )

  then
    $call.setDevice_type_desc($device_typeLookup.getDevice_type_desc());
end

It's a simple enough rule: join on the device_type field.  Unfortunately, this rule and a few others like it are taking FOREVER to insert.  Even when I cut the number of BINNING_INPUT facts in working memory down from 8M to 10k.

This feels like a basic Drools question.  But I can't seem to find any help from google.

Please advise!

Thanks in advance,

Dave Martin