Transaction and Rule Supportfor Workflow Management -A Retrospective on the WIDE

Architecture

Paul GrefenCS Department & CTIT

University of Twente

Workflow on IntelligentDistributed database

Environment

DBMS

WFMS

WFAM

TT

DBMS

DBMS EXT.

WFMS

WFA

MT

TW

IDE

Ap

pro

ach

• Extended transaction support– Loose global transactions (saga)– Strict local transactions (nested)

• Active rule support– Decoupled execution mode– Workflow, data, external, time events

• Data support– Object-oriented client interface– Relational server interface– IDL-SQL/C++ compiler support

DB

MS

Ext

ensi

ons

• Advanced data support versus workflow support– reusability of advanced data support

• Extended transaction support versusactive rule support– orthogonal and flexible semantics– adaptability of transaction/rule support

• WIDE integrated workflow system vs.commercial DBMS– portability of WIDE WFMSO

rth

ogon

al A

rch

itec

ture

DBMS

BAL

WorkflowEngine

TransactionSupport

Active RuleSupport

WorkflowClient

Ove

rall

WID

E A

rch

itec

ture

orthogonalityorth

ogonality

DistributionDistribution

WorkflowEngine

BAL

DBMS

LTM

Local Trans.Interface

GlobalTrans. Man.

GTLT

Tra

nsa

ctio

n S

up

por

t

CORBA

OCI

WorkflowEngine

Interpreter

Scheduler

TimeManager

Ext. EventManager

ExternalApplications

BAL

Oracle TS Events

Act

ive

Ru

le S

up

por

t

• Commercial RDBMS (Oracle 7.2)– Robust basic data support– Flat ACID transactions, basic triggers– Client/Server coupling (OCI)

• CORBA (ILU)– Flexible distribution– Transparent communication

Infr

astr

uct

ure

• Functionality– Does the system do what was intended?

• Performance– Does the system offer reasonable

performance?

• Maintainability– Is the system easy to implement and

modify?

Loo

kin

g B

ack

at

the

Des

ign

• Local transaction functionality– Limited flexibility for atomicity control– Limited transactional multi-DB access– X/Open TPM extension helps

• Rule execution functionality– Decoupled rule execution model– Orthogonal transaction/rule semantics– Limited intra-business transaction rules

Fu

nct

ion

alit

y in

Ret

rosp

ect

• C/S connection to DBMS critical– Large numbers of small transactions– Physical channel creation expensive– Reuse already created channels– Keep channels in channel pool– Modification local to LTI– Further extensions possible:

• channel creation in idle time

• statistical forecasting of channel usage

Per

form

ance

in R

etro

spec

t

• Software development in 3 organizations– Sema (ES), POLI (IT), UT (NL)

• High level of flexibility required

• Orthogonal architecture design

• Standard internal module architectures

• CORBA/IDL interface specification

• Empty Shell integration

• Complexity may lead to semantic problems though ….

Mai

nta

inab

ilit

y in

Ret

rosp

ect

• Transfer of WIDE technology to FORO commercial WFMS(SEMA)

• Use of transaction concepts in cross-organizational contexts(UT, CrossFlow project)

• Unbundling of active rule engine functionality for non-WFM purposes(POLI, SEMA)

• Book on WIDE developments(Kluwer Academic, January ‘99)F

urt

her

Dev

elop

men

ts