8:23 p.m.
We have over 15,000 rows in the database and we need to apply the rules on
this data. We are thinking of doing the following.
a. Read the data from the database in batches
b. Create beans for the data that we just read
c. Run the rules on the beans (this results in setting some attributes
on the bean)
d. Save the beans back to the database
As you can see, there is some overhead in reading the data from the
database, performing the OR mappings, and writing the data back to the
database. Is there a way to avoid some of these steps? Can you please
suggest some techniques that we can use to improve the performance? Also, I
was wondering whether we can configure Drools to operate directly on the
data in the database.
Thanks
Bhaskar
12:27 p.m.
As far as I know, Drools can only reason over facts in the working memory. It
can not directly "select" from RDBMS. You have to load in all data items
from the database and validate them in memory by Drools.
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12:56 p.m.
You can access Objects from external resources using the "from" keyword (in
fact the use of this with Hibernate named queries is a documented use-case,
IIRC).
The Objects are not however inserted into WorkingMemory using "from" are
should therefore be time-constant as their properties will not be included
in truth maintenance.
If you require the Objects as Facts in WorkingMemory for the inference
engine to reason with, you can write rules using "from" that insert into
WorkingMemory.
On 14 February 2011 11:27, hyjshanghai <hyjshanghai(a)gmail.com> wrote:
As far as I know, Drools can only reason over facts in the working memory.
It
can not directly "select" from RDBMS. You have to load in all data items
from the database and validate them in memory by Drools.
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http://drools-java-rules-engine.46999.n3.nabble.com/Applying-rules-on-the...
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1:05 p.m.
Beware with the use of the FROM Conditional Element, because if you are
using another fact that doesn't come from the DB and you change them, the
FROM CE will be continuously evaluated causing the execution of tons of
queries multiple times.
My two cents.
Greetings
2011/2/14 Michael Anstis <michael.anstis(a)gmail.com>
You can access Objects from external resources using the
"from" keyword (in
fact the use of this with Hibernate named queries is a documented use-case,
IIRC).
The Objects are not however inserted into WorkingMemory using "from" are
should therefore be time-constant as their properties will not be included
in truth maintenance.
If you require the Objects as Facts in WorkingMemory for the inference
engine to reason with, you can write rules using "from" that insert into
WorkingMemory.
On 14 February 2011 11:27, hyjshanghai <hyjshanghai(a)gmail.com> wrote:
>
> As far as I know, Drools can only reason over facts in the working memory.
> It
> can not directly "select" from RDBMS. You have to load in all data items
> from the database and validate them in memory by Drools.
> --
> View this message in context:
>
http://drools-java-rules-engine.46999.n3.nabble.com/Applying-rules-on-the...
> Sent from the Drools - User mailing list archive at Nabble.com.
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
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- Salatino "Salaboy" Mauricio -
1:13 p.m.
Sure, I agree, this would be an example:-
rule "Family smurf"
when
MyFact( smurf == "pupa" )
ExternalObject( ) from placeHolder.namedQuery("Smurfs")
then
//Do something
end
If MyFact is updated in other rules the list will be refreshed "from" the
named query.
So the preference might be to load the Objects into WM first:-
rule "bootstrap"
salience -100
when
$list : List( ) from placeHolder.namedQuery("Smurfs")
then
for(ExternalObject o : $list ) {
insert( o );
}
end
rule "Family smurf"
when
MyFact( smurf == "pupa" )
ExtenalObject( )
then
//Do something
end
You could also have a layer of caching between the rules and RDBMS too; so
your only performing a read from cache with the "from" keyword and not RDBMS
itself.
How you choose is obviously up to you and the volatility of your data read
from RDBMS.
2011/2/14 Mauricio Salatino <salaboy(a)gmail.com>
Beware with the use of the FROM Conditional Element, because if you
are
using another fact that doesn't come from the DB and you change them, the
FROM CE will be continuously evaluated causing the execution of tons of
queries multiple times.
My two cents.
Greetings
2011/2/14 Michael Anstis <michael.anstis(a)gmail.com>
You can access Objects from external resources using the "from" keyword (in
> fact the use of this with Hibernate named queries is a documented use-case,
> IIRC).
>
> The Objects are not however inserted into WorkingMemory using "from" are
> should therefore be time-constant as their properties will not be included
> in truth maintenance.
>
> If you require the Objects as Facts in WorkingMemory for the inference
> engine to reason with, you can write rules using "from" that insert into
> WorkingMemory.
>
>
> On 14 February 2011 11:27, hyjshanghai <hyjshanghai(a)gmail.com> wrote:
>
>>
>> As far as I know, Drools can only reason over facts in the working
>> memory. It
>> can not directly "select" from RDBMS. You have to load in all data
items
>> from the database and validate them in memory by Drools.
>> --
>> View this message in context:
>>
http://drools-java-rules-engine.46999.n3.nabble.com/Applying-rules-on-the...
>> Sent from the Drools - User mailing list archive at Nabble.com.
>> _______________________________________________
>> rules-users mailing list
>> rules-users(a)lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/rules-users
>>
>
>
> _______________________________________________
> rules-users mailing list
> rules-users(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/rules-users
>
>
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- Salatino "Salaboy" Mauricio -
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4 comments
4 participants
participants (4)
-
Gorantla, Bhaskar (GE Capital) -
hyjshanghai -
Mauricio Salatino -
Michael Anstis