F. Bancilhon, W. Kim, H. Korth, A model of CAD transactions, in: Proceedings of the Conference on Very Large Databases (VLDB), 1985, pp. 25--33.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....activities of cooperating users and showed that correct merged histories remain legal. Furthermore, we discussed an algorithm which utilizes the idea of history merging to implement CoAcTs exchange operations (import, delegate, and save) As pointed out in the introduction, checkout models [BKK85, KSUW85] do not ex plicitly address cooperation among co workers although they appear in tandem with versions and configurations. Checked out objects are reserved for exclusive access until a later checkin. Another drawback is that all objects needed to perform a specific task have to be checked out ....

F. Bancilhon, W. Kim, and H. Korth. A model of CAD transactions. In Proc. of the 11th Int. Conference on Very Large Databases, pages 25-33, Stockholm, Sweden, August 1985.

....to hold the lock in X mode in order to make sure that Ci cannot change the resp. Oi. 4. 1 Controlled Downward Inheritance The need for controlling the lock mode in which inferiors can access an offered object becomes more obvious if we consider an example from a cooperative design environment [Bancilhon85, Kim84]. Fig. 5 shows a design task which is structured as a three level transaction hierarchy. Assume, transaction B generates an object O, describing the interface of a work piece. Transactions C and D, which are children of B, design subparts of the work piece and therefore require read access to the ....

Bancilhon, F., Kim, W., Korth, H.F.: A Model of CAD Transactions. Proc. 11th Int. Conf. on VLDB, Stockholm, Aug. 1985, 25-33.

....groupware systems strive to make the actions of each user visible to the others. Thus, the shielding of one user from 102 seeing the intermediate states of another s transaction is in opposition to the goals of interactive groupware systems. There has been some work on opening up transactions [Banc85]; however, the emphasis of this work has been on coordination of nested transactions rather than elimination of the constraints imposed by locking and transactions. Our solution to concurrency control is to lock data before it is modified (it resembles the fences mechanism) For instance, ....

Bancilhon, G., Kim, W., and Korth, H.F. "A Model of CAD Transactions. " Proc. Intl. Conv. on Very Large Data Bases, pp. 25-33, 1985.

....specific consistency constraints. The DBMS can use these specifications rather than serializability as a basis for maintaining consistency. Several researchers have studied the nature of concurrent behavior in advanced applications, and have arrived at new requirements for concurrency control [Bancilhon et al. 85; Yeh et al. 87] 1. Supporting long transactions: Operations on objects in design environments (such as compiling source code or circuit layout) are often long lived. If these 19 operations are embedded in transactions, these transactions, unlike traditional ones, will also be long lived. ....

....concurrent access to shared objects or non serializable interaction. Instead, the concept of database consistency preservation needs to be refined along the lines of the previous section to allow non serializable cooperative interaction. Such a refinement can be based on four observations [Bancilhon et al. 85] 1) design efforts are usually partitioned into separate projects, where each project is developed by a team of designers; 2) available workstations provide multiple windows, in which multiple tasks can be executed concurrently by the same designer; 3) projects are divided into subtasks were ....

[Article contains additional citation context not shown here]

Bancilhon, F., Kim, W., and Korth, H. A Model of CAD Transactions. Proceedings of the 11th International Conference on Very Large Data Bases, Morgan Kaufmann, August, 1985, pp. 25-33.

.... systems [32] Many properties of a transaction (fault tolerance, controlled concurrent access to objects, commitment of a consistent set of changes, explicitly requested commit or abort, and nested activities) are essential for multi user SDEs, as well as other cooperative work such as CAD CAM [3]. An archetypical example would be enclosing within a transaction all activities of a programming team responding to a modification request for a deployed software product. These activities different programmers browsing and editing overlapping sets of source files, compiling and linking, ....

Francois Bancilhon, Won Kim and Henry Korth. A Model of CAD Transactions. In 11th International Conference on Very Large Databases, pages 25-33. Stockholm, August, 1985.

.... that involve long interactive database sessions and cooperation among multiple users [Bernstein 87] Semantics based concurrency control [Salem et al. 87, Garcia Molina and Salem 87, Beeri et al. 88, Kutay and Eastman 83, Korth and Speegle 90, Pu et al. 88] and cooperative transaction models [Bancilhon et al. 85, El Abbadi and Toueg 89, Dowson and Nejmeh 89, Klahold et al. 85, Skarra and Zdonik 89, Kaiser 90] were proposed to overcome some of the limitations of serializable transactions. As with software process models, none of the new transaction models was found appropriate for all applications. ....

....control problem that results from allowing concurrent rule chains in RBDE. We also present a list of requirements that any satisfactory solution to this problem must meet; this list is based on requirements that other researchers have proposed in the literature [Bernstein and Goodman 81, Bancilhon et al. 85, Yeh et al. 89] We describe our solution in four chapters. Chapter 4 describes the nested transaction model and the NGL locking protocol for detecting serializability conflicts between concurrent rule chains. In chapter 5, we extend EMSL with consistency predicates, and 20 introduce the SCCP ....

Bancilhon, F., Kim, W., and Korth, H. A Model of CAD Transactions. In 11th International Conference on Very Large Data Bases, pages 25-33. Morgan Kaufmann, Stockholm, Sweden, August, 1985.

....updated resources are retained for the duration of the transaction. Interaction with other concurrent activities is even more difficult, since resource access from all other transactions must be serialized either before or after the transaction. One representative model of CAD transactions [1], developed by Bancilhon, Kim, and Korth, tries to solve these difficulties with an extended transaction model tailored for CAD activities. In this model, the CAD environment is divided into six hierarchical conceptual levels: project transactions, cooperating transactions, clients subcontractors, ....

....split transactions, we do not intend to settle the debate of whether serializability is too restrictive for open ended activities. Nevertheless, powerful serializable access is useful even in a system that admits non serializable operations. Therefore, like a significant portion of previous work [1, 4], we restrict our discussion to serializable access. Another non goal of this paper is the philosophical discussion of whether in principle an atomic transaction can be split completely. We only remind the gentle reader that in Physics atoms were split years ago. The rest of this paper is ....

[Article contains additional citation context not shown here]

F. Bancilhon, W. Kim, and H.F. Korth. A model of CAD transactions. In Proceedings of the Eleventh International Conference on Very Large Data Bases, pages 25-- 33, Stockholm, August 1985.

....which requires a serial execution, 2) a parallel split by a compatible dependency, and (3) an unnesting split otherwise. Similarly, AJoin operations are specialized into join by group and join by merge. Comparing with the early research on split transactions [18] and Cooperative Transactions [1, 17], these activity restructuring meta operations are novel in at least two aspects. First, a formal notion of the validity of activity restructuring operations is introduced to guarantee the correctness of new activities generated by activity split or activity join operations. Second, the techniques ....

....activities. Moreover, very few activity models or workflow systems proposed so far, to our knowledge, provide the adequate support for dynamic split and join of activities of deeply nested structures, ensuring the correctness of resulting activities. A number of extended transaction models (ETMs) [6, 7, 8, 1, 16, 17, 18, 20] have been proposed, each targeting at a particular subset of the whole spectrum of interactions possible in advanced application environments. Therefore, an ETM alone is not sufficient for organizing complex cooperative activities that may require the whole spectrum of interactions [3] ....

[Article contains additional citation context not shown here]

F. Bancilhon, W. Kim, and H. Korth. A model for cad transactions. In Proceeding of the 11th International Conference on Very Large Databases, pages 25-- 33. Morgan Kauffman, 1985.

....to the notion of nested transactions, or sub transactions [19] This allows for long lived transactions to be decomposed so that consistency both within a sub transaction and that of its context can be maintained separately. Applications of nested transactions include cooperative transactions [1], ones that combine toward a common final goal. All of these works go beyond serializability by using encapsulation, and using the semantics of both the database and the transaction in order to restrict concurrency in order to maintain consistency. The work in this paper serves to be an ....

F. Bancilhon and H. Korth, A model of CAD transactions, Proc. of the 11th Intl. Conf. on Very Large Databases, August 1985, 25--33.

....models (ETMs) and workflow systems [10, 11, 16, 17, 22, 20, 9] have been proposed to support diversified new application requirements. For example, Sagas [11] extend the traditional transaction model by including an automated compensation capability within sagas. Cooperative Transactions [2], Split Transactions [20] and Transaction Groups [17] were proposed for capturing the interactions among transactions required in advanced applications. Many of these ETMs were targeted at a particular domain of applications, offering adequate correctness only for this domain [6] Other ETMs ....

.... targeted at a particular domain of applications, offering adequate correctness only for this domain [6] Other ETMs capture only a subset of the spectrum of interactions found in any complex information systems [15] Cooperation among sibling transactions is supported by Cooperative Transactions [2, 20, 17], although the interactions among siblings are either restricted to leaf node transactions in order to support serializable split transactions or limited to static and one shot design of transaction groups. Therefore, it is usually difficult to introduce added concurrency and improve the ....

F. Bancilhon, W. Kim, and H. Korth. A model for cad transactions. In Proceeding of the 11th International Conference on Very Large Databases, pages 25--33. Morgan Kauffman, 1985.

....in a CAD system could be : Add the design for an ALU to this VLSI chip design. The transaction includes a large chunk of interactive design work, before the transaction can finish, and the design be considered consistent again. Such transactions are called design or long transactions [12, 51, 62, 65, 70]. Traditional locking of the whole design would obviously be too restrictive. There are a number of ways of approaching this problem. The ORION system [64] uses a system of shared and private databases. The shared database can be accessed by any user, whereas each user has exclusive access to ....

....prototypes. In this section, a selection of some of the systems most frequently described in the literature are reviewed. Note that the ZEITGEIST, IRIS and POSTGRES systems would be included in this section, were they not described elsewhere in sections 2.6.2, 2.3.4 and 2.3.5. ORION ORION [12, 13, 15, 44, 62, 63, 64, 65] is a research prototype, a version of which is now being marketed as ITASCA [11] ORION is implemented in Common LISP and supports all the usual object oriented features including composite objects and multivalued attributes. The development of ORION identified a taxonomy of modifications that ....

Bancilhon, F., W. Kim and H. F. Korth, "A Model of CAD Transactions", Proceedings of 11th International Conference on Very Large Databases, Stockholm. pp.25-33. 1985.

....meta operations introduced, users may restructure ongoing activities, in anticipation of uncertain duration or unpredictable development, to allow performance improvement through release of early committed resources or transferring ownership of uncommitted resources. 1 Introduction Since 1985 [2] significant results have been produced in the area of database support for collaborative applications. At the same time, the continual expansion of network bandwidth and increase in computing speed raised both the quantity and complexity of data types. In addition, the growing sophistica ....

F. Bancilhon, W. Kim, and H. Korth. A model for cad transactions. In Proceeding of the 11th International Conference on Very Large Databases, pages 25-- 33. Morgan Kauffman, 1985.

....lacking in functionality and performance when used for applications that involve reactive (endless) open ended (longlived) and collaborative (interactive) activities. Hence, various extensions to the traditional model have been proposed, referred to herein as extended transactions [Mos81, VRS86, BKK85, PKH88, KLS90, GGK 91, BHMC90, FZ89, SZ89, Elm91] Compared to the traditional transaction model, these models associate broader interpretations with the four transaction notions mentioned above to provide enhanced functionality while increasing the potential for improved performance. Upon ....

Bancilhon, F., Kim, W., and Korth, H. A model of CAD Transactions. In Proceedings of the 11th International Conference on VLDB, pages 25--33, 1985. 10.6 Bibliography 47

....to support cooperating transactions. These models are based on the checkin checkout paradigm [FZ89] K 85] Each subtransaction integrates two databases: a private database containing objects accessed by the transaction itself, and a semi public database [K 84) or subcontractor database [BKK85] containing objects that can be checked out by subtransactions. The semi public database or subcontractor database permits exchange of intermediate results (upward downward commit in [K 84] and checkout enable, disable in [BKK85] Checkin and checkout have to be a two phase protocol. After the ....

....itself, and a semi public database [K 84) or subcontractor database [BKK85] containing objects that can be checked out by subtransactions. The semi public database or subcontractor database permits exchange of intermediate results (upward downward commit in [K 84] and checkout enable, disable in [BKK85] Checkin and checkout have to be a two phase protocol. After the first checkin not checkouts are authorized. Upward downward commit (respectively enable and disable) are based on optimistic protocols and augmented lock protocols The main characteristics such cooperation is the collaboration ....

F. Bancilhon, W. Kim, H. Korth. A model of CAD transactions. In Proc. 11 th VLDB. August 1985. Morgan Kaufmann Publishers.

....the synchronous nature of traditional transaction processing systems, becomes an increasingly serious performance bottleneck in some advanced applications, especially the ones involving long duration transactions and hot spot data. Applications like computeraided design and manufacturing (CAD CAM) [7, 9, 8, 76, 44] are often long lived and may consist of multiple steps executed on collections of complex data objects. In these applications, transactions are likely to hold resources for a relatively long time, which exclusively locks out the executions of other transactions that need the resources. As a ....

F. Bancilhon, W. Kim, and H. Korth. A model of CAD transactions. In 11th International Conference on Very Large Databases, pages 25--33, Stockholm, Sweden, August 1985.

....to the resource conflict problem which results from the need to maintain data consistency. Data contention appears as a consequence of overly strict consistency constraints enforced by serializability. In many advanced applications [13, 28] such as computer aided design, manufacturing(CAD CAM) [7], and scientific data man 2 agement [12] traditional concurrency control methods such as the two phase locking protocol [30] have been shown to be inadequate for maintaining data consistency due to severe data contention, which significantly degrades system performance. In distributed systems, ....

....the synchronous nature of traditional transaction processing systems, becomes an increasingly serious performance bottleneck in some advanced applications, especially the ones involving long duration transactions and hot spot data. Applications like computeraided design and manufacturing (CAD CAM) [7, 9, 8, 76, 44] are often long lived and may consist of multiple steps executed on collections of complex data objects. In these applications, transactions are likely to hold resources for a relatively long time, which exclusively locks out the executions of other transactions that need the resources. As a ....

F. Bancilhon, W. Kim, and H. Korth. A model of CAD transactions. In Proceedings of the Eleventh International Conference on Very Large Data Bases, pages 25--33, Stockholm, August 1985. 159

....by allowing schedules that otherwise would have been disallowed to avoid cascading aborts. Other researchers have presented work based on formal notions of program correctness, in which application semantics is encoded in predicates that must be satisfied by transactions. Bancilhon et al. [1] require each transaction to provide an invariant of the database that its execution maintains; Korth and Speegle [18] require each transaction to supply precondition and postcondition predicates. Since satisfaction of arbitrary predicates would be infeasible, the authors provide for an ....

Bancilhon, F., Kim, W., and Korth, H. A model of CAD transactions. In Proceedings of 11th International Conference on Very Large Databases 1985, pp. 25--33.

....by the weaker requirement that only assertions about the state need be preserved. The special requirements of a CAD system encourage the use of transaction semantics to determine when tasks can be executed and how integrity constraints should be maintained. An early paper on this subject is [10] [3] and [18] describe a nested transaction model for a CAD environment that preserves database consistency constraints but does not force executions to be serializable. They do not provide a mechanism for choosing the subtransactions. 4 Concurrency and Transaction Semantics We formally characterize ....

F. Bancilhon, W. Kim, and H. Korth. A model of cad transactions. In Proc. of Eleventh Int'l Conf. on Very Large Databases, 1985.

No context found.

F. Bancilhon, W. Kim, H. Korth, A model of CAD transactions, in: Proceedings of the Conference on Very Large Databases (VLDB), 1985, pp. 25--33.

....literature [Sandhu et al. 1996] to the collaborative design problem. We focus on the relation between actors, their roles and the solid model geometry. This is in contrast to other work on access control in collaborative CAD which has focused mainly on database synchronization transaction issues [Bancilhon et al. 1985]. Representing Actors and Roles We define a hierarchical RBAC framework where: 1. Entities include a set of actors, A = a 1 and a set of roles R = r 1 ; 2. Actor Role Assignment, AR, is a relation (possibly manyto many) of actors to roles: AR AR; 3. Role Hierarchy, RH, ....

Bancilhon, F., Kim, W., and Korth, H. F. 1985. A Model of CAD Transactions. In Pirotte, A. and Vassiliou, Y., editors, VLDB'85, Proceedings of 11th International Conference on Very Large Data Bases, pp. 25--33. Morgan Kaufmann.

....to two phase locking is that it may require locks to be held for a substantial fraction of a transaction s duration, thus restrict ing the amount of parallelism. In a CAD environment, transactions are often of long duration. This property exacerbates the disadvantages of two phase locking. In [BANC85], we proposed a transaction model for CAD transactions in which serializability is not required. Instead, a consistency constraint is stated for the database and an invariant is defined for each transaction. Executions that preserve the requisite invariants are allowed, including some executions ....

....that are collaborating closely on a design. Other types of interaction among transactions may be represented also, such as a client subcontractor interaction, in which a subtransaction may run 2 concurrently with its parent, but is logically equivalent to a procedure call by the parent. In [BANC85], we presented a few simple schemes for concurrency control within the model. In this paper, we present an approach to concurrency control that is designed especially for this CAD transaction model. First, we extend the granularity DAG of IGRA76] to represent versions of CAD objects. We then ....

[Article contains additional citation context not shown here]

Bancilhon, F., W. Kim, and H. F. Korth, "A Model of CAD Transactions," Proc. 11th International Conference on Very Large Data Bases, pp. 25-33 (1985).

No context found.

F. Bancilhon, W. Kim, and H.F. Korth. A Model of CAD Transactions in Proc. of the 1 lth Int. Conf. on Very Large Database, pages 25--33, 1985.

No context found.

F. Bancilhon, W. Kim, H. Korth, "A model for CAD transactions" Proceedings of the 11th international conference on very large databases, pp. 25-33, August 1985.

No context found.

F. Bancilhon, W. Kim, and H. F. Korth. A model of CAD transactions. Proc. of the VLDB conference, 1985, Stockholm, pp. 25-33.

No context found.

Bancilhon, F., Kim, W., and Korth, H. F. (1985). A Model of CAD Transactions. In Proceedings of the Eleventh International Conference on Very Large Data Bases, pages 25--33, Stockholm, Sweden. 140

First 50 documents  Next 50

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC