[rules-users] [Column(f1=='v1', f2=='v2')] vs [Column(f1=='v1') Column(f2== 'v2')]

[Edson Tirelli]

    Vlad,

    The constructions are semantically different. In 3.0.x as default, 
JBoss Rules will not allow the same fact to match more than one column. 
So if you write:

Column(f1=='v1')

Column(f2=='v2')


    Your rule will only match if there are 2 different objects that each 
match one of the constraints. While, if you write:

Column(f1=='v1', f2=='v2')


   It will require a single object that matches both constraints.

   Also, the optimizations (indexing, hashing, etc) are done on a field 
constraint basis.

   So, if you have one rule with :

 Column(f1=='v1', f2=='ONE_VAL')


   And   another rule with:

 Column(f1=='v1', f2=='ANOTHER_VAL')


   The constraint f1=='v1' will be evaluated only once. Although, to 
help optimization, you must keep the constraints that repeat over 
multiple patterns as the first constraints for each collumn, in the same 
order.

   []s
   Edson


Olenin, Vladimir (MOH) wrote:

>Hi,
>
> 
>
>I wonder what is the difference (performance-wise, etc) between these two
>constructs:
>
> 
>
>Column(f1=='v1', f2=='v2')
>
> 
>
>And
>
> 
>
>Column(f1=='v1')
>
>Column(f2=='v2')
>
> 
>
>?
>
> 
>
>Both of them should select the same 'Column' facts (where Column.f1=='v1' &&
>Column.f2='v2'), correct? Is one construct more preferable then another one?
>Does JBossRules hash only the evaluation result of the 'full column' OR
>individual field constraints as well? From what I understand, only the full
>'Column' is defined as an (alpha?) node while individual constraints within
>the node can not be further optimized, correct? 
>
> 
>
>Meaning, if I have another condition somewhere like this:
>
> 
>
> Column(f1=='v1', f2=='ANOTHER_VAL')
>
> 
>
>[f1=='v1'] constraint would have to be reevaluated again, while if I define
>constraints through two 'separate' columns and the new constraint as
>
> 
>
> Column(f1=='v1)
>
> Column(f2=='ANOTHER_VAL')
>
> 
>
>only the new constraint would have to be reevaluated. Do I understand it
>right?
>
> 
>
>Thanks!
>
> 
>
>Vlad
>
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>  
>


-- 
 Edson Tirelli
 Software Engineer - JBoss Rules Core Developer
 Office: +55 11 3124-6000
 Mobile: +55 11 9218-4151
 JBoss, a division of Red Hat @ www.jboss.com