1. Field of the Invention
The present application generally relates to the effective and efficient transitioning of a business model from one phase to the next phase and, more particularly, to a policy-driven approach which specifies how to phase out of an existing business process phase and how to migrate to the newer or next business process phase without loss of critical data or metrics.
2. Background Description
In order to function effectively in today's business environment, organizations must have visibility in their business activities and operation performance at all times. This allows them to stay competitive and profitable. Business Performance Management (BPM) is a new generation of enterprise data management that focuses on monitoring business operations. BPM solutions must be able to efficiently process business events, compute business metrics, detect business situations, and provide the real-time visibility of Key Performance Indicators (KPIs). A BPM solution lifecycle involves five steps, as illustrated in
A naive evolution mechanism is “hot swap”, i.e., when the new solution is deployed, the existing solution is forced to shutdown. Such an approach is easy to implement; however, it is not sufficient for supporting continual BPM lifecycles. First, the hot swap evolution may lead to information lost. The BPM is an event-driven stateful system, wherein business solutions are detected based on occurrences of events and the status of context instances. When a solution is forced to shutdown manually, the business situation detection that may be still in process is interrupted, which may eventually result in missing the situation. Second, the hot swap is not practical in some business scenarios. In some cases, the existing and new BPM solutions need to be running coexisting for a period of time, where the transition from the existing BPM solution to the newer one should be performed. For example, a BPM solution is developed and deployed to monitor a business process. Later on, based on the monitoring results and analysis of the BPM, the action that re-engineers business processes is taken. Therefore, the old process needs to be migrated to the new process. Accordingly, when a new BPM solution that monitors the new process is developed and deployed, the evolution of BPM solutions needs to be synchronized with business process migration. Thus, other than hot swap, transition based evolution is required.
Implementing a dynamic evolution of the BPM solution that enables continual business performance improvement is by no means a trival task. There are three major challenges:
According to the present invention, a policy-driven approach to implement dynamic BPM solution evolutions is used. In general, a policy provides an abstraction of system behaviors that allow users to manage the system without needing to understand extraneous details. The policy-driven approach differs from existing evolutions solutions. In existing approaches, co-existing based solution transitions are not supported. Also, developers need to focus on time-consuming platform dependent implementation. In contrast, the policy-driven approach supports wide spectrums of evolution policies. Further, solution providers can concentrate on business processes and observation models, without worrying about platform specific implementation details. Therefore, BPM solutions can be continually improved by enabling another lifecycle, as the solution evolution is performed systematically through the policy-driven architecture.
Briefly stated, the salient features and contributions of the present invention are as follows:
The foregoing and other objects, aspects and advantages will be better understood from the following detailed description of a preferred embodiment of the invention with reference to the drawings, in which:
The requirements of a BPM solution are captured by an observation model. The specification of observation models is given by the observation meta-model. An example of an observation model is shown in
The information in an observation model is typically constructed top-down. Formally, an observation model, as illustrated in
There are two aspects regarding the operation of an observation model, as illustrated in
item.stockLevel:=minus(item.stockLevel, customer.order.lineItem.amount)
In this expression, minus is a dependency vertex, and item.stockLevel and customer.order.lineItem.amount are metric vertices. The item.stockLevel and customer.order.lineItem.amount are inputslots and item.stockLevel is an outputslot of dependency minus. The metrics in a map expression may belong to different contexts. For example, in the above expression, two metrics are from context item and customer, respectively. The relationship supported by a metric network includes functional, probabilistic, system dynamics and extensible user-defined dependency. We focus here on explicit functional dependency. It should be noted that the execution of an expression can be triggered by an incoming event, value changes of a metric, or occurrence of a situation.
In order to realize the BPM evolution, we extend the observation meta-model with Evolution Policy to describe the process of BPM solution evolution. There are two aspects in the evolution process: (1) How to pase out the existing model transactionally (sunset policy); and (2) how to migrate context instances and associated elements (i.e., metrics and situations) from the existing version to the newer one (context mapping policy).
A collection of sunset policies define the process of phasing out a BPM solution, where a policy is denoted as T[P]|A. T indicates type of contexts or events in the observation model. P is a predicate for selecting either context or event instances. A is the action for managing the selected instances. There are two kinds of policies, according to contexts and events in the observation model for the existing BPM solution.
Context migration policy defines how context instances are migrated to the newer solution, which can be notated as: Cs[P]|Ct(E), where Cs is the source context in the existing BPM solution, P is a predicate for selecting context instances, Ct is the target context type that selected context instances migrated to, and E is a list of expressions that define element mapping relationship between the source and the target context. In general, an expression can be denoted as:
V′C.λ:=χ(V.C1,λ1,V.C2.λ2, . . . , V.Cn.λn,V.γ1,V.γ2, . . . , V.γm,V.ε1,V.ε2, . . . , V.εk) (1)
where χ is the operator and there are three kinds of operands: metrics (λi), events (γi) and external data sources (εi).
An example of migration policy can be V. Customer:: customer[customer.totalReturnAmount>0]|V′.Customer (V′.Customer.customerID:=V.Customer.customerID; V′.Customer.totalReturnAmount:=V.Customer.totalReturnAmount), which means for monitor context instance customer (the context type is Customer), if its metric totalReturnAmount's value is greater than zero, then migrate this context instance customer to version V2's monitor context Customer. Actually, from the new solution perspective, migrating context instance from the existing solution can be considered as creating a new context instance4. Therefore, each key metric much have one element mapping policy to set the value. Other than key metrics, non-key metric mapping policies may also be required for BPM solution evolution. It should be noted that if V′C.λ is a key metric in the new solution, then all the operands must be static (i.e., the values are not updated after the value is assigned).
There are some constraints when migrating the context instance from the existing BPM solution to the new one. First, if the context instances are direct descendants of the root context in the existing BPM solution, then the context that migrated to the new BPM solution should also be the direct descendent of the root context. Second, if both context instances and the context that migrated to the new BPM solution are not direct descendents of the root context, then the context instances' parent context should be also migrated. Further assume that context V.C1 maps to context V′.C′1, if context V.C1's parent context of V.C2 maps to V′.C′2, then V′.C′1's parent context is V′.C′2 in the new BPM solution V′.
In our earlier work, we adopted a compiling and interpreting hybrid approach to realize the execution of observation models. We distinguished three kinds of application logic in a BPM solution: common logic, information logic and model specific logic. The common logic is defined in meta-model level, which is applied to any observation model. One example of common logic is the routine for processing events. The information logic includes information organization in the observation model. Model specific logic (e.g., map expression) is unique to each individual model. Our solution consists of three components, namely model transformer, model compiler and model interpreter, as illustrated in
If evolution policies are considered as a declarative program, like the observation model, there are also two approaches to executing a program; namely, interpreting and compiling. The advantage of interpreting policies is that it is easy to realize the evolution policy execution because the policy interpreter can be easily integrated with the BPM runtime engine as the runtime engine maintains all the model information. However, the logic of selection context instances and mapping expression can be very complicated. Therefore, developing an interpreter that can execute map expressions optimally becomes difficult, given that the operators in constructing map expression can be rational, set, vector, scalar, etc. Further, the elements referenced in mapping expressions are not limited to the same context. To locate the operands in mapping expressions, the interpreter needs to navigate through the hierarchy of contexts at runtime, which may also incur performance penalties. Such performance penalties may greatly impact the on-going situation detections.
Adopting a compiling approach can improve evolution execution performance by generating customized code for individual expressions; however, generated code is a stand alone component, which is impractical to integrated with the BPM runtime engine. Such an approach can support hot swapped-based evolution; however, it fails to support transition-based evolution. For example, in a transition-based evolution, some context instances need to phase out transactionally. Without integrating with the observation runtime engine, context instances may be terminated when the situation detection is still in progress.
In order to take advantage of the hybrid framework of
One of the key steps in the policy-driven approach according to the present invention is to transform policies. Further, in order to facilitate compilation, the policy transformer pre-processes mapping expressions. As discussed earlier, the design of the evolution policy language aims to facilitate the creation of policies. However, the organization of the data is not suitable for efficient runtime access. We designed the policy transformer that reorganizes the policies information according to the schema shown in
Other than re-organizing information in evolution policies, the policy transformer also pre-processes policies. In particular, it collects mapping expressions that should be executed during the context evolutions and the result is stored in the field of expressions in table ContextEvolution. Further, the policy transformer also pre-processes mapping expressions by determination of the navigation paths for each operand.
In the framework of the present invention, context migration consists of two basic steps: (1) migrating the context instances and their key values; and (2) migrating the non-key metrics. Accordingly, there are two aspects of runtime state validation: (1) a context instance duplication test; and (2) validating freshness of operands in non-key metric mapping policies.
As discussed earlier, mapping a context instance from one BPM solution to a new one can be considered as creating a new context instance in the new solution. Therefore, a context instance duplication test is required. In the present invention, customized code is generated to facilitate the efficient runtime state validation. Before getting into the details about code generation, we first briefly describe the design of runtime data store schema which the generated code runs on. The unified data schema is shown in
Given the above unified datastore, we present how to generate queries to perform a duplication test. Assuming the target context instance's type is μ. The goal is try to search for the context instance that has same key metric values as created from the key-metric mapping expression. The first step is generating queries to retrieve the context instances that belong to the migrating context type.
ρ(p,πinstanceID(CcontextID=μ)) (2)
In the next step, we illustrate how to retrieve its key metric value, assuming there is a list of key metrics (λ1, λ2, . . . , λk) for the monitor context and each metric has a list of attributes (α1, α2, . . . , αn). If the αj's data type is string, then the query generated for retrieving λi's αj is:
ρ(υi,j,πstringValue,positionID(σV.itemName=λ
This query joins the table Values with context instances that have the same context type as the migrated instance. Also assuming attribute αj has l dimensions and the size of each dimension is dk(1<k<1), the extra queries about the dimension [x1, x2, . . . , xl] (0<xk<dk) is generated as:
ρ(di,j,k,(σD.dimensionOrder=k^D.sequenceID=x
For example, if αj's dimension number is 2 and the dimension that needs to be retrieved is [3,5], then two queries are generated as it is a two dimensional expression:
ρ(di,j,1,(σD.dimensionOrder=1^D.sequenceID=3D))
and
ρ(di,j,2,(σD.dimensionOrder=2^D.sequenceID=5D))
It should be noted that each above query is according to a dimension of the attribute of key metric, which selects the tuple in table dimensions. Using the above example, by equijoining di,j,1 and di,j,2, we can have
ρ(di,j[χ1, χ2, . . . , χl]positionID{di,j,k,kε[1 . . . l]}) (5)
In the next step, by equijoining vij with dij using dimenionsID to search the fields, we have a query:
ρ(υi,j′[χ1,χ2, . . . ,χl],(υi,jpositionIDdi,j[χ1,χ2, . . . ,χl])) (6)
where v′i,j[x1, x2, . . . , xl] represents the value of a key metric's attribute value in position [x1, x2, . . . , xl]. Assuming the key-metric value in position [x1, x2, . . . , xl] that computed from mapping expression is λ[x1, x2, . . . , xl]. The query for testing whether these two values are equal is:
ρ(ci,j[χ1, χ2, . . . , χl],πinstanceID(υi,j′[χ1, χ2, . . . ,χl]stringValue=λ[χ
Therefore, by equijoining the instanceID for every position of every attribute in every key metric, we have the following query to test whether the context instance exists in the target solution.
ρ(c,πinstanceID(instanceID{ci,j[χ1,χ2, . . . ,χl]}),
iε[1 . . . m], jε[1 . . . n], χkε[0 . . . dk), kε[1 . . . l] (8)
In the runtime, generated queries are executed when the execution of all the key metric mapping policies are completed, in order to check whether a new context instance needs to be created on the target BPM solution.
In the second step of migrating context instance, non-key metric mapping policies are executed. The operands may be updated in the on going process (i.e., the existing BPM solution); that is, in parallel with the migration process. If that is the case, then the metric value that was computed based on the mapping expression in the migrated context instance is out of date. In such a situation, the execution of executing the non-key metrics mapping policies need to wait until the event processing is completed.
In order to efficiently determine the freshness of operand values in mapping policies, we analyze the observation model of the existing BPM solution to determine the metrics or situations that may be updated during the processing of the event (See Algorithm 1). The basic idea of the algorithm is to use the event as a trigger to initiate the expression computation (line 8) and then recursively use the output of expression to trigger other expressions (line 23). It should be noted that triggering a map computation can be either an event (line 10) or value change of a metric (line 14) or occurrence of a situation (line 18). By accumulating the output of the triggering expression (line 21), the list of elements that maybe updated during the processing of the event is obtained.
At runtime, each context instance keeps a list of events (i.e., Event [ ] currentProcessingEvents) that are being processed. When executing the non-key metric mapping policy, if an operand's hosting context instance's currentProcessingEvents is not empty and the operand is in updateMetrics ( ) of any event in currentProcessingEvents, then the execution of the policy needs to be paused until the event processing is completed. At the same time, the runtime engine also queues events that may update the metric value until the execution of mapping policy is completed (in both existing and new BPM solutions). Therefore, we can not only guarantee the freshness of the metric value, but also the completeness of the event processing.
According to the invention, in order to transactionally shutdown the existing BPM solution, executing sunset policies and event processing are integrated into the model interpreter. The model interpreter loads and executes the runtime classes that are generated from context instance selection predicates in the sunset policy. The selected context instances are terminated according to the time stamp given by the policy. Execution of event handling policies is integrated with the event correlation process. When a new event is received, the model interpreter loads and executes the runtime classes that were generated from context instance selection predicates to determine whether to ignore or correlate to the existing context instance or create a new context instance.
In the execution of context migration policy, the model interpreter loads and executes the runtime classes that are generated from context instance selection predicates in the migration policies. For the selected context instance, the model interpreter executes the key-metric mapping expression to compute the key metric value. Then it executes the generated code for the duplication test. If a duplicated instance is found, the found context instance is then the target instance for non-key metric migration. If the migrated instance is not a duplication, a new context instance is created in the target solution using the key metric values, and then non-key metric migration is performed.
While the invention has been described in terms of a single preferred embodiment, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims.
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