field binding performance implications
by Olenin, Vladimir (MOH)
Hi,
We need to generate drl file from a template. Since the format of the rules
parameters doesn't fall very well within decision table concept (the
parameters are not 'homogeneous', so each row in the input excel table can
mean different things), we decided to define the rules by automatically
generating drl files from a set of templates. To cover more cases with a
single template we'd need to bind every field of column by default, even if
the binding would not be used.
For example (Freemarker syntax is used in the template below):
Rule ${ruleId}
When
Record ( $account : account ${operation} ${value}
)
....
Then
.....
End
In the example above, 'operation', 'value' and 'ruleId' are objects in the
data model that we merge with the template. One case of the rule would be
when both 'operation' and 'value' are empty strings. This will result in
this LHS: Record ( $account : account ). Another case might be when
'operation' is '==' string and 'value' is '1': Record ( $account : account
== 1 ).
The above is a simplified template to demonstrate the point. The real
business data model for facts (Record object) would have around 10 fields
and we can have ~ 5 to 10 columns per rule. I wonder what kind of
performance implications does field binding bring? Are there any or this is
being optimized / filtered out by some preprocessor?
In other words, is there significant difference in performance for the
following LHS expressions:
1) Record ( $account : account, $name : name == 'xxx', $balance : balance
> 100, ....)
Vs
2) Record (name == 'xxx', balance > 100, ....)
Providing the functionality of both of these LHS expressions is the same and
field bindings in LHS #1 are never used throughout the rule.
Thanks,
Vlad
