A Flexible Failure-Recovery Model for Workflow Management Systems

Abstract

In this paper, we propose a new failure-recovery model for workflow management systems (WfMSs). This model is supported with a new language, called the workflow failure-handling (WfFH) language, which allows the workflow designer to write programs so that he can use data-flow analysis technology to guide the failure recovery in workflow execution. With the WfFH language, the computation of the end compensation point and the compensation set for failure recovery can proceed during the workflow process run-time according to the execution results and status of workflow activities. Also, the failure-recovery definitions programmed with the WfFH language can be independent, thereby dramatically reducing the maintenance overhead of workflow processes. A prototype is built in a Java-based object-oriented workflow management system, called JOO-WfMS. We also report our experiences in constructing this prototype.

A New Concurrency Control Language for Transactional Process in Service-Oriented Architecture

“…Referring to Figure 2, process A involves a transaction that has five critical activities: A 2 , A 3 , A 4 , A 5 , and A 6 . The execution of critical activities may cause failures for which the entire transaction must be cancelled and rolled back by applying compensation to some of the executed critical activities [9]. At the beginning of a transaction, the process executes an entry operation that sends some defeasible logic rules and variable definitions to the concurrency control service (CCS).…”

“…However, the execution of critical activities may cause failure [9], in which case the workflow process has to inform the CCS using a fail-and-exit operation and perform the required compensation. This operation may cause other transactions that are in the "accepted-withblocking-commit" state to stop the execution of critical activities and perform the required compensation.…”

“…Consider the situation where a transaction failure occurs after a process has written a shared resource and assume that some other processes have already read the object and proceeded with their own transactions. A solution to the inconsistency problem is to rely on compensation mechanisms to ensure the atomicity of transactions in the presence of failures [9], [10], [11]. Transaction compensation involves executing a compensation subroutine that attempts to undo the effects of the previous execution of it.…”

Sentence Similarity Measures to Support Workflow Exception Handling

“…However, these processes face the need to handle exceptions that fall outside the normal control flow (Casati et a., 2000). Exceptions occur commonly in workflows (Kumar and Wainer, 2005;Sadiq et al, 2005;Hwang and Lee, 2005). Workflow exception is any deviation from an ideal collaborative process that uses the available resources to achieve the task requirements in an optimal way (Klein and Dellarocas, 2000).…”

“…Therefore, the occurrence of workflow exceptions is unavoidable and there is a need to handle those exceptions efficiently. Rule-based reasoning (RBR), Model-based reasoning (MBR) and case-based reasoning (CBR) are approaches being used to handle exceptions in workflow systems (Luo et al, 2003;Hwang et al, 2005). Workflow exceptions may require human intervention to establish proper handlers.…”