Showing papers on "Distributed transaction published in 1994"

Continuously available database server having multiple groups of nodes, each group maintaining a database copy with fragments stored on multiple nodes

Abstract: A database server with a "shared nothing" system architecture has multiple nodes, each having its own central processing unit, primary and secondary memory for storing database tables and other data structures, and communication channels for communication with other ones of the nodes. The nodes are divided into first and second groups that share no resources. Each database table in the system is divided into fragments distributed for storage purposes over all the nodes in the system. To ensure continued data availability after a node failure, a "primary replica" and a "standby replica" of each fragment are each stored on nodes in different ones of the first and second groups. Database transactions are performed using the primary fragment replicas, and the standby replicas are updated using transaction log records. Every node of the system includes a data dictionary that stores information indicating where each primary and standby fragment replica is stored. The records of each database table are allocated as evenly as possible among the table fragments. A transaction manager on each node responds to database queries by determining which fragment of a database is being accessed by the query and then forwarding the database query to the node processor on which the primary replica of that fragment is stored. Upon failure of any one of the data processors in the system, each node updates the information in its data dictionary accordingly. In addition, the fragment replicas made unavailable by the node failure are regenerated and stored on the remaining available nodes in the same node group as the failed node.

System and method for creating interactive electronic systems to present information and execute transactions

Abstract: A fully integrated system and method for production and presentation of dynamically linked electronic presentation of information to front end client computers, for providing dynamic access to information from front end client computers, and for formulating, transmitting and processing transactions based upon information presented and accessed is disclosed. The system and method provides for production of a system for presentation of information to front end client computers in the form of customized electronic books linked to databases of the information presented. The electronic books further include forms for entry of transaction requests based upon such information. The forms are coded for execution of the particular transaction requested thereon by a transaction management system connected to one or more transactional databases.

System and method for processing a customized financial transaction card

Abstract: The present invention provides for a system and method of performing financial transactions which include a financial card that stores pre-selected transaction instructions corresponding to one or more financial transactions, such as cash withdrawal, or bill payment, or the like. These cards are used with one or more terminals which read the instructions on the card, interpret those instructions and execute the interpreted instructions to conduct one or more of said financial transactions. Preferably, the terminal--after determining from the instructions on the card what functions, i.e., financial transactions, are available to the card user--displays those options. The user then selects one of the financial transactions; the terminal based on the selection and the instructions corresponding to the selected function, executes the transaction.

Fault-tolerant transaction-oriented data processing

Abstract: In transaction processing systems, it is known for resource-updating operations within a transaction to be backed out at the request of an application program following detection of error conditions during processing of the transaction. If the error condition is very likely to recur, it may be undesirable for the operations request to be presented to the application exactly as before. A transaction-oriented data processing system and a method of transaction-oriented data processing are provided in which operation requests or data packets may be marked to be excluded from the effects of application-requested backouts.

Method and apparatus for using an independent transaction processing application as a service routine

Abstract: A system is disclosed for using an independent transaction processing application as a service routine for a client application where the independent transaction processing application is programmed for independent input and output. The independent transaction processing application does not have be reprogrammed for usage as a service routine. A transaction manager provides transaction control for a service request from the client application. A display processing system manages input and output associated with processing the service request. A database management system that is used by the independent transaction processing application distinguishes whether the transaction manager or the independent transaction processing application is providing transaction control.

Commitment ordering for guaranteeing serializability across distributed transactions

Abstract: Serializability across distributed transactions is guaranteed by selectively committing and aborting or delaying transactions to enforce an order of commitment that is the same as an order of performance of conflicting component operations of the transactions. A first memory access operation in a first transaction, for example, conflicts with a second memory access operation in a second transaction when the two memory access operations reference the same memory location and at least one of the operations is a write operation. The transaction processing system may permit a second transaction to read data written by a write operation of a first transaction before the first transaction is committed. In this case, depending on the respective order in which the two conflicting operations occur, the order of commitment is enforced, possibly by aborting either of the two transactions, to ensure that the order of commitment is the same as the order of the operations. The conflicts, for example, are detected when the addresses are determined during preparation of the transactions. The component operations may be scheduled for most efficient use of the computer system capabilities. In a multiprocessor system in which a global coordinator communicates with a plurality of transaction processors by way of "prepare" and "commit" commands, the commitment order is referenced to delay acknowledging that a transaction has been "prepared" until the transaction's "abort set" has been minimized.

Ensuring relaxed atomicity for flexible transactions in multidatabase systems

Abstract: Global transaction management requires cooperation from local sites to ensure the consistent and reliable execution of global transactions in a distributed database system. In a heterogeneous distributed database (or multidatabase) environment, various local sites make conflicting assertions of autonomy over the execution of global transactions. A flexible transaction model for the specification of global transactions makes it possible to deal robustly with these conflicting requirements. This paper presents an approach that preserves the semi-atomicity (a weaker form of atomicity) of flexible transactions, allowing local sites to autonomously maintain serializability and recoverability. We offer a fundamental characterization of the flexible transaction model and precisely define the semi-atomicity. We investigate the commit dependencies among the subtransactions of a flexible transaction. These dependencies are used to control the commitment order of the subtransactions. We next identify those restrictions that must be placed upon a flexible transaction to ensure the maintenance of its semi-atomicity. As atomicity is a restrictive criterion, semi-atomicity enhances the class of executable global transactions.

Method and apparatus for data verification and position reporting in an automated trade transactions processing system

Abstract: An automated trade processing system including a record keeper for receiving participant mutual fund transaction requests. The record keeper also aggregates the participant mutual fund transaction requests by mutual fund into omnibus plan transaction requests. These requests are then transmitted in at least one file which has a plurality of fields of information about the omnibus plan transaction requests. A host processor, interacting with the record keeper, receives the at least one file, processes the omnibus plan transaction requests, verifies at least one of the plurality of fields of information, and trade-acknowledgment confirms the omnibus plan transaction requests to the record keeper. The host processor then transfers the omnibus plan transaction requests to a transaction executor which executes the omnibus plan transaction requests. The trade-acknowledgment confirmation occurs at a time prior to execution of the omnibus plan transaction requests. The transfer agent executes the omnibus plan trades and trade-execution confirms them to the host processor. The host processor compares the trade-acknowledgement confirmation and the trade-execution confirmation and generates a mismatch file which is then transmitted to the at least one record keeping systems. This cycle occurs in less than a day and enables the record keeping system to perform daily valuation of all participant accounts in its various plans.

ASSET: a system for supporting extended transactions

Abstract: Extended transaction models in databases were motivated by the needs of complex applications such as CAD and software engineering. Transactions in such applications have diverse needs, for example, they may be long lived and they may need to cooperate. We describe ASSET, a system for supporting extended transactions. ASSET consists of a set of transaction primitives that allow users to define custom transaction semantics to match the needs of specific applications. We show how the transaction primitives can be used to specify a variety of transaction models, including nested transactions, split transactions, and sagas. Application-specific transaction models with relaxed correctness criteria, and computations involving workflows, can also be specified using the primitives. We describe the implementation of the ASSET primitives in the context of the Ode database.

Transaction implementation in video dial tone network

Abstract: Disclosed is a system and method of implementing purchasing and other transactions in an integrated multimedia communication system by utilizing an intelligent peripheral of an advanced intelligent telephone network which peripheral includes a voice recognition module for providing control capability based on received voice signals, and a voice verification module which includes a storage database for individualized voice authentication templates. The processor also includes a transaction manager module for controlling interaction with external money management devices such as automated teller machines (ATM's). The service control point of the network maintains a separate database for identifying a specific voice identification template on the basis of recognition and identification of an incoming signal as associated with a specific subscriber for a terminal and/or a telephone station. The peripheral also includes an internal data communications system carrying information between the processor, the voice verification module, the transaction monitor and the signaling communications interface.

Cash alternative transaction system

Abstract: Applicant's invention includes a cash-alternative transaction processing system and associated methods based on the use of smart cards, purchase point smart card reader/writer transaction register systems, and clearing center processors. Also includes are elements relating to use of smart cards in vending machines.

Using tickets to enforce the serializability of multidatabase transactions

Abstract: To enforce global serializability in a multidatabase environment the multidatabase transaction manager must take into account the indirect (transitive) conflicts between multidatabase transactions caused by local transactions. Such conflicts are difficult to resolve because the behavior or even the existence of local transactions is not known to the multidatabase system. To overcome these difficulties, we propose to incorporate additional data manipulation operations in the subtransactions of each multidatabase transaction. We show that if these operations create direct conflicts between subtransactions at each participating local database system, indirect conflicts can be resolved even if the multidatabase system is not aware of their existence. Based on this approach, we introduce optimistic and conservative multidatabase transaction management methods that require the local database systems to ensure only local serializability. The proposed methods do not violate the autonomy of the local database systems and guarantee global serializability by preventing multidatabase transactions from being serialized in different ways at the participating database systems. Refinements of these methods are also proposed for multidatabase environments where the participating database systems allow schedules that are cascadeless or transactions have analogous execution and serialization orders. In particular, we show that forced local conflicts can be eliminated in rigorous local systems, local cascadelessness simplifies the design of a global scheduler, and that local strictness offers no significant advantages over cascadelessness. >

Method for synchronizing transaction processing in a distributed heterogeneous system

Abstract: The invention provides transaction synchronization in the form of COMMIT processing in a distributed, heterogeneous database system wherein some resources are synchronized to a transaction by a single-phase commit procedures while other resources synchronize by multi-phase commit procedures. The invention invests an application requestor at an application site with authority to represent all single-phase commit resources in multi-phase commit processing.

Submission of transactions from mobile workstations in a cooperative multidatabase processing environment

Abstract: In a multidatabase environment with mobile computers involved, the nature of computing is such that the user may not wait for the submitted global transaction to complete before disconnecting from the network. In this paper, a basic architectural framework to support transaction management in multidatabase systems is proposed and discussed. A simple message and queuing facility is suggested which provides a common communication and data exchange protocol to effectively manage global transactions submitted by mobile workstations (MWS). The state of global transactions is modelled through the use of transaction sub-queues. The proposed strategy allows an MWS to submit global transactions and then disconnect itself from the network to perform some other tasks, thereby increasing processing parallelism and independence. >

Processing real-time transactions in a replicated database system

Abstract: A database system supporting a real-time application has to provide real-time information to the executing transactions. Each real-time transaction is associated with a timing constraint, typically in the form of a deadline. It is difficult to satisfy all timing constraints due to the consistency requirements of the underlying database. In scheduling the transactions it is aimed to process as many transactions as possible within their deadlines. Replicated database systems possess desirable features for real-time applications, such as a high level of data availability, and potentially improved response time for queries. On the other hand, multiple copy updates lead to a considerable overhead due to the communication required among the data sites holding the copies. In this paper, we investigate the impact of storing multiple copies of data on satisfying the timing constraints of real-time transactions. A detailed performance model of a distributed database system is employed in evaluating the effects of various workload parameters and design alternatives on the system performance. The performance is expressed in terms of the fraction of satisfied transaction deadlines. A comparison of several real-time concurrency control protocols, which are based on different approaches in involving timing constraints of transactions in scheduling, is also provided in performance experiments.

Bounded ignorance: a technique for increasing concurrency in a replicated system

Abstract: Databases are replicated to improve performance and availability. The notion of correctness that has commonly been adopted for concurrent access by transactions to shared, possibly replicated, data is serializability. However, serializability may be impractical in high-performance applications since it imposes too stringent a restriction on concurrency. When serializability is relaxed, the integrity constraints describing the data may be violated. By allowing bounded violations of the integrity constraints, however, we are able to increase the concurrency of transactions that execute in a replicated environment. In this article, we introduce the notion of an N-ignorant transaction, which is a transaction that may be ignorant of the results of at most N prior transactions, which is a transaction that may be ignorant of the results of at most N prior transactions. A system in which all transactions are N-ignorant can have an N + 1-fold increase in concurrency over serializable systems, at the expense of bounded violations of its integrity constraints. We present algorithms for implementing replicated databases in N-ignorant systems. We then provide constructive methods for calculating the reachable states in such systems, given the value of N, so that one may assess the maximum liability that is incurred in allowing constraint violation. Finally, we generalize the notion of N-ignorance to a matrix of ignorance for the purpose of higher concurrency.

Transparent transaction coordination between distributed networks having different communication protocols

Abstract: A mechanism is provided which allows transparent transaction processing to occur between distributed networks using the AIX or SNA protocols. The present invention will convert between the AIX standard of Two Phase Commit/Presumed Abort (2PC/PA) and the SNA standard of Two Phase Commit/Presume Nothing (2PC/PN). The Presumed Abort Protocol will optimize operations by reducing the number of messages between sites participating in the transaction, and the amount of transaction state information maintained at a site. Thus, any messages needed will be generated and transaction status information will be maintained in order to satisfy a Standard 2PC/PN protocol, when sites within a SNA network are participating in an AIX transaction. Further, the present invention will discard, or ignore any extraneous messages which are received while sites within an AIX network are participating in a SNA transaction.

Revising transaction concepts for mobile computing

Abstract: It is expected that in the near future millions of users will have access to on-line distributed databases through mobile computers. The restrictions imposed by the nature of the wireless medium and the resulting mobility of data consumers and data producers make traditional transaction models inadequate. In this paper, we investigate means for providing transaction support appropriate for mobile environments. Specifically, we define a model that ensures a weaker notion of consistency, accounts for mobility, and provides for recovery.

Transaction processing system and method

Abstract: A transaction processing system, adapted for use in a computer system having a host computer running applications and user terminals connected to the host computer, determines the transaction attributes for each transaction received by the host computer and dynamically associates a transaction protocol to be used in processing that particular transaction. The transaction protocol specifies such attributes as synchronization paradigm and flow control. The synchronization paradigm and flow control are used only for as long as the transaction remains in the system and are used only for that transaction.

Routing transactions in the presence of failing servers

Abstract: Failures are detected in servers of a transaction processing system, and transactions are routed to less failure prone servers in the system. Servers in the transaction processing system which are faulty for some transaction classes but good for others are detected, and such servers are used in a judicious manner to maximize the throughput and minimize the response time of the system. Error prone servers are occasionally probed to determine if they have improved in terms of their error characteristics. The mechanism implemented consists of three elements. The first is the selection of a routing algorithm based on the state of the transaction processing system. Second, transactions are used to probe systems considered too faulty for use in order to determine if they have improved in terms of their failure characteristics. Finally, soft ABENDs are detected. The algorithm for transaction routing to detect and control the problem of failing servers in a transaction processing system consists of two parts: The first part routes transactions to servers based on the length of the server queues, the response time of the transactions (i.e., queuing delay plus processing delay), and the perceived failure rate. The second part of the algorithm ensures that error prone servers are not completely ignored. Occasional transactions are used to probe servers in order to determine if they have improved in terms of their error characteristics.

Specification and management of extended transactions in a programmable transaction environment

Abstract: A Transaction Specification and Management Environment (TSME) is a transaction processing system toolkit that supports the definition and construction of application-specific extended transaction models (ETMs). The TSME provides a transaction specification language that allows a transaction model designer to create implementation-independent specifications of extended transactions. In addition, the TSME provides a programmable transaction management mechanism that assembles and configures a run-time environment to support specified ETMs. The authors discuss the TSME in the context of a distributed object management system (DOMS), and describe specifications of extended transactions and corresponding configurations of transaction management mechanisms. >

Method for forwarding a call to a temporarily utilized portable telephone

Abstract: A distributed service management system for providing communication services comprises a plurality of individual service management systems operated by a plurality of different service providers. Each service management system includes its own local database and an Interactive Distributed Transaction Monitor (IDTM) that allows locally running applications to access the local database as well as remote databases belonging to remotely located service management systems. The interfaces serve to integrate multiple individual service management systems into a single multidatabase transaction management system. The distributed service management system can be used to provide special personal communication services involving multiple service providers, such as call forwarding to a temporarily rented mobile telephone.

Common cryptographic key verification in a transaction network

Abstract: A stored value transaction system has a plurality of value storing transfer devices, including at least one local device, collection device, consolidation device and settlement device. First and second transfer devices are provided for performing a value information transfer transaction between each other. First and second cryptographic verifiers within the first and second transfer devices, respectively, provide individual first and second secure transaction determinations and permit the value information transfer transaction in accordance with the first and second individual secure transaction determinations. The first and second cryptographic verifiers include respective first and second pluralities of encryption keys. The first and second pluralities of encryption keys have at least one common encryption key whereby both the first secure transaction determination and the second secure transaction determination are made in accordance with the common encryption key. The common encryption key may be a network authority key.

Deadlock detecting device

Abstract: Start, commit and abort of transactions in a computer system are managed by a task manager. When a certain transaction locks a certain resource, this information is registered in a lock manager. Accordingly, when a transaction requests for gaining a resource, the lock manager can determine that the resource is already locked, if any, by another transaction. In such a case, the transaction should wait for the termination of the other transaction, so that this information is registered in a wait-for-graph table. A deadlock detector determines whether the deadlock is caused according to the registered information in the wait-for-graph table.

Electronic market transaction system for detecting orders reaching a prescribed frequency of failure to increase chance of establishing transactions

Abstract: The present invention proves an electronic dealing system, which electronically performs matching processing between information on transaction orders placed by order side customers and information on transaction orders placed by hit side customers so as to establish transactions the electronic dealing system detects orders for which hit requests have been made, but for which transactions have failed to be established for a long period of time and eliminates those orders from the electronic dealing market Further, when transactions fail to be established due to factors other than the transaction price and the transaction amounts, other customers which would help establish the transactions between order side and hit side customers are found so as to increase the number of transactions which are established

Priority assignment in real-time active databases

Abstract: Active databases and real-time databases have been important areas of research in the recent past. It has been recognized that many benefits can be gained by integrating active and real-time database technologies. However, there has not been much work done in the area of transaction processing in active real-time databases. This paper deals with an important aspect of transaction processing in active real-time databases, namely the problem of assigning priorities to transactions. In these systems, time-constrained transactions trigger other transactions during their execution. We present various policies for assigning priorities to parent, immediate and deferred transactions executing on a multiprocessor system and then evaluate the policies using simulation. The simulator has been validated by comparing to three sets of published results. Our new results demonstrate that dynamically changing the priorities of transactions depending on their behavior (triggering rules), yields a substantial improvement in the number of triggering transactions that meet their deadline. >

System and method for creating an object oriented transaction service that interoperates with procedural transaction coordinators

Abstract: A system and method for efficiently employing procedural transaction managers from an object oriented transaction processing system. Implementation classes are introduced to bridge selected functions from an object oriented transaction processing system into a procedural system. Bridging allows both the reuse of existing procedural transaction managers and interoperation between procedural and object transactions systems which eases migration to new object oriented systems. Implementation classes include methods necessary to manage information necessary to use a procedural transaction API and to manage information returned by the procedural API.

Semantics-based multilevel transaction management in federated systems

Abstract: A federated database management system (FDBMS) is a special type of distributed database system that enables existing local databases, in a heterogeneous environment, to maintain a high degree of autonomy. One of the key problems in this setting is the coexistence of local transactions and global transactions, where the latter access and manipulate data of multiple local databases. In modeling FDBMS transaction executions the authors propose a more realistic model than the traditional read/write model; in their model a local database exports high-level operations which are the only operations distributed global transactions can execute to access data in the shared local databases. Such restrictions are not unusual in practice as, for example, no airline or bank would ever permit foreign users to execute ad hoc queries against their databases for fear of compromising autonomy. The proposed architecture can be elegantly modeled using the multilevel nested transaction model for which a sound theoretical foundation exists to prove concurrent executions correct. A multilevel scheduler that is able to exploit the semantics of exported operations can significantly increase concurrency by ignoring pseudo conflicts. A practical scheduling mechanism for FDBMSs is described that offers the potential for greater performance and more flexibility than previous approaches based on the read/write model. >

Relative Serializability: An Approach for Relaxing the Atomicity of Transactions

Abstract: In the presence of semantic information, serializability is too strong a correctness criterion and unnecessarily restricts concurrency. We use the semantic information of a transaction to provide different atomicity views of the transaction to other transactions. The proposed approach improves concurrency and allows interleavings among transactions which are non-serializable, but which nonetheless preserve the consistency of the database and are acceptable to the users. We develop a graph-based tool whose acyclicity is both a necessary and suffcient condition for the correctness of an execution. Our theory encompasses earlier proposals that incorporate semantic information of transactions. Furthermore it is the first approach that provides an effcient graph based tool for recognizing correct schedules without imposing any restrictions on the application domain. Our approach is widely applicable to many advanced database applications such as systems with long-lived transactions and collaborative environments.

A framework for enforceable specification of extended transaction models and transactional workflows

Abstract: A variety of extensions to the traditional (ACID) transaction model have resulted in a plethora of extended transaction models (ETMs). Many of these ETMs are application-specific, i.e. they are designed to provide correctness guarantees adequate for a particular application, but not others. Similarly, an application-specific ETM may impose restrictions that are unacceptable in one application, yet required in another. To define new ETMs, to determine whether an ETM is appropriate for an application, and to integrate ETMs to produce new ETMs, we need a framework for ETM specification and reasoning. In this paper, we describe such a framework. Our framework supports implementation-independent specification of ETMs described in terms of dependencies between transactions. Dependencies are specified using dependency descriptors. Unlike other transaction specification frameworks, dependency descriptors use a common set of primitives, and are enforceable, i.e. can be evaluated at any time during transaction execution to determine whether issued operations violate ETM specifications. We discuss specifications of (i) structure dependencies between transaction states, and (ii) correctness dependencies for serializability, various cooperative and temporal correctness criteria, and recoverability. We give ETM specification examples for a telecommunications application illustrating the definition of a new application-specific ETM using our framework.