[rules-users] Poor performance from a simple join

[Mark Proctor]

On 19/12/2011 17:03, David Martin wrote:
> No, Mark... You nailed it. My "guards" were reversed and my rules were 
> no longer matching anything.
>
> The change you suggest below seems to do the trick though... Putting 
> the nested accessor first took a 90s process of 10k records down to 12s.
>
> Phew!  I will double and triple check my work now, but thanks a 
> million!  I would never have thought swapping the order could have 
> such a huge impact on performance.
In your case what you have there is not a nested accessor. "device_type" 
is a direct field of BINNING_INPUT. It use to be in earlier versions of 
drools that fields must be to the left of the operator, and this would 
have blown up. However edson has been working on improving things for 
"free form" expressions, to remove artificial barriers to authoring 
constraints.  I suspect though that things that do not fall into the 
legacy layout are written as evals, and thus you miss out on the 
indexing. In short because you put $call to the left of the operator 
Drools was not intelligent enough to know that this was not a variable 
constraint, and it executed as an eval. We'll be improving that 
intelligence over time.

M
>
> Dave
>
> From: Mark Proctor <mproctor at codehaus.org <mailto:mproctor at codehaus.org>>
> Reply-To: Rules Users List <rules-users at lists.jboss.org 
> <mailto:rules-users at lists.jboss.org>>
> Date: Mon, 19 Dec 2011 16:59:25 +0000
> To: <rules-users at lists.jboss.org <mailto:rules-users at lists.jboss.org>>
> Subject: Re: [rules-users] Poor performance from a simple join
>
> On 19/12/2011 16:58, Mark Proctor wrote:
>> sorry I misread that, you've put the binding first, not using a 
>> nested accessor.
>>
>> Currently you have
>> $call              : BINNING_INPUT()
>> $device_typeLookup : LU_DEVICE_TYPE( $call.device_type == device_type )
>>
>> try rewriting it as:
>> $call              : BINNING_INPUT()
>> $device_typeLookup : LU_DEVICE_TYPE( device_type == $call.device_type )
>>
>> I know edson was working on making such that the order no longer 
>> matters, I'm not sure what progress he made on that and he's away at 
>> the moment so can't answer. It may be that he's already done that 
>> work and it's correctly getting executed as an indexed constraint, or 
>> it might be rewritting to an eval. Hopefully edson can answer when he 
>> gets back.
>>
>> Ass Mauricio suggests, maybe you can restrict the number of instances 
>> for BINNING_INPUT and LU_DEVICE_TYPE too.
> ooops
> s/Ass/As/
>>
>> Mark
>>
>>
>>
>>
>> On 19/12/2011 16:51, Mark Proctor wrote:
>>> Nested accessors are not currently indexed, because we cannot assure 
>>> their immutability:
>>> $call.device_type
>>>
>>> If people changed indexed nested accessors, without correctly 
>>> notifying the engine it would result in integrity problems.
>>>
>>> If you have a large number of these, trying flattening the model, 
>>> such as you would do in a database.
>>>
>>> Mark
>>> On 19/12/2011 16:23, David Martin wrote:
>>>> Folks:
>>>>
>>>> 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
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> rules-users mailing list
>>>> rules-users at lists.jboss.orghttps://lists.jboss.org/mailman/listinfo/rules-users
>>>
>>
>
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