RE: [Obe-developer] Re: obe

[Adrian P. <ad...@bt...>]

Good day Jorge,
 
Your boss's concern about performance is entirely reasonable - it's bound to
be faster to search the ProcessInstance table than to join it with
AttributeInstance as many times as there are attribute references in your
WHERE clause. The reason for the current design is, of course, to provide a
generic, extensible design where the set of process attributes is specified
in XPDL rather than being hard-coded in the database schema and the
persistence POJOs or POJIs.

For any given workflow-enabled application it is likely that there will be a
small set of business keys that are always required in order to look up the
process for a known business context, so clearly it would be advantageous to
introduce a mechanism to support this efficiently.

I suppose it would be possible to subclass the
ProcessInstanceEJB/ProcessInstanceBean to introduce additional attributes,
but there's a couple of places in the code where you'd need to enumerate the
new attributes to ensure that the correct SQL is generated for a given
predicate.

Another approach might be to introduce a user-defined association table or
'request object' containing just the business keys and the
processInstanceId. This approach would only require a single join.

I believe Hibernate may have the ability to create a logical view which
merges physical tables.

However, both the above approaches would require some degree of change in
the OBE runtime. Also, be aware that OBE parses SQL predicates and re-writes
them using parameter markers so that all database activity can be performed
using prepared statements. In order to do this the SQL parser needs to be
aware of which tables various attributes reside in - adding another table
would necessitate changes to this part of the runtime.

On the subject of metrics, I do not have any information myself. All I can
suggest is that you measure it for yourself and decide whether it's fast
enough for your present purposes. Perhaps you could introduce performance
enhancements at a later date if it proves necessary?

Thanks,

Adrian.

Adrian Price
Architect & Lead
The Open Business Engine
mailto:adr...@us...

"tenax propositi, altiora peto"
________________________________

From: obe...@li...
[mailto:obe...@li...] On Behalf Of Jorge
Middleton
Sent: Monday, May 08, 2006 8:48 PM
To: obe...@li...; obe...@li...
Subject: [Obe-developer] Re: obe


Hello,

I write because I need your help. 

The subject is, that my boss's distrust about the performance relative to
search process instance based on attributes's filter.    
We  have 2 attributes that always be in all processes (business attributes)
and he says that this attributes must be in ProcessInstance table so the
search process is faster.  
I think that this is true but also it less flexible and restrictive to
future's enhanced so I need some statistics data about time of search or
something like that.

Somebody could give me an advice?

Thank in advance 
Jorge