Y. Breitbart and A. Silberschatz, "Multidatabase Update Issues," In Proceedings of the ACM SIGMOD International Conference on Management of Data, June 1988.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....should be equal to the number of bookings stored for that agent in the summary database. If it holds initially, this constraint can be assured by executing all the updates to both databases as components of an atomic multidatabase transaction, which is globally serialized with other transactions [3]. This, however, is impossible if the database interfaces do not provide visible two phase commit facilities. And, if they provide a visible precommit state, it would still be inefficient, requiring resources to be locked at remote sites. Instead, we assume that the interdatabase integrity is ....

Y. Breitbart and A. Silberschatz, "Multidatabase Update Issues," In Proceedings of the ACM SIGMOD International Conference on Management of Data, June 1988.

....use it to mean a system managing multiple databases without a global schema. The essential component of such an MDBS is a language used to manage interoperable databases. Local database systems are loosely coupled. Local autonomy is fully supported. Dayal and Hwang [6] Breitbart and Silberschatz [1], Lu et al. 13] and many others use Current address: Microsoft Corporation, One Microsoft Way, Redmond, WA 98052 6399, USA 374 Q. ZHU AND P. A. LARSON the term MDBS to mean a system managing multiple databases with one or more global schemas. The essential component of such an MDBS is a ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of the ACM SIGMOD Conference, pages 135--142, 1988.

....databases. The integration of several database systems will result in a distributed, heterogeneous database system. Many researchers have focused their work on the data model and the query and update language of such a system[LR 82, TBC 87, NS 88, KDN 90] Others focus on transaction management [BS 88, BST 90, DE 89, DEL 89, GS 87, LT 89, Pu 88, WV 90] A global transaction in an integrated database system is executed by the different existing database systems. Hence, the global transaction management has to deal with different existing transaction managers, i.e. different interfaces, ....

....must not start subtransactions in other existing database systems, since this would violate global control. In addition, local transactions which are not under control of the central system are not allowed, as global serializability is very hard to achieve without a common global control [GP 86, BS 88, DE 89, DEL 89] DBMS 1 Transaction Manager Figure 1: System Architecture central system local system network Communication Manager Communication Manager . local system Communication Manager DBMS n DBMS 1 Transaction Manager Transaction Manager Communication Manager Global ....

Breitbart, Y., Silberschatz, A.: Multidatabase Update Issues. Proceedings ACM SIGMOD, 1988.

....M.SPICINESS= strong The following is a script that shows the submission and execution of such a query in our interactive user interface. M Y R I A D Q U E R Y F O R M U L A T O R 11 = 1] STARTSESSION [2] BEGINTRANS [3] EXECQUERY [4] COMMIT [5] ABORTTRANS [6] ENDSESSION [7] SHUTDOWN [8] QUIT option: 3 Please input your SQL query followed by semicolon 1 SELECT R.RNAME, R.PHONE, R.WDAYHRS, R.WENDHRS FROM RES R, MENU M, BUFFET B 2 WHERE R.RNAME=M.RNAME AND R.RNAME=B.RNAME AND R.RATING=5 AND 3 M.SPICINESS= strong ; The ....

....to provide internal control information (i.e. autonomy) and the various transaction management mechanisms adopted by local DBMSs (i.e. heterogeneity) Over the past five years, transaction management has become one of the most active research areas in FDBSs. Many algorithms have been proposed [6, 5, 24, 25, 10, 16, 11, 23, 2, 14]. Not until recently did some researchers start to investigate the relative performance of the various proposed algorithms [13] However, such investigation is still in its early stage, and it is not clear how different algorithms behave in a real system. Therefore, one of our design choices in ....

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Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proc. of ACM SIGMOD Int'l. Conf. on Management of Data, 1988.

....local autonomous transactions to co exist. Local autonomous transactions are executed outside the control of the MDBS whereas global transactions are controlled by the MDBS. Various approaches for the management of at transactions in MDBS have been described in the recent years [BGMS92, ZE93, BS88, GRS91, MRKS92, GRS94] Enforcing global serializability in MDBS is difcult because there may be indirect conicts between global transactions caused by local autonomous transactions at a particular site which the MDBS is not aware of. A LDBS cannot be forced to externalize any information that ....

....enormously. 6 Various approaches for the management of at global transactions in MDBS have been described in the literature. The proposed approaches deal with the global serializability problem in presence of design and execution autonomy of the participating database systems [BGMS92, ZE93, BS88, GRS91, GRS94] We utilize the ticket method which guarantees global serializability by the explicit introduction of local con icts between global transactions [GRS94] Other solutions for nested global transactions are multilevel transaction management [Wei91] which requires the speci cation of ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proc. of the ACM SIGMOD Conference on Management of Data, June 1988.

....even if an application updates only part of the interrelated information. 3. Existing applications operating on interrelated information can execute concurrently with new distributed applications that need to share the same data. Most of the prior work on multidatabase transaction management [5, 6, 18, 19, 22, 27, 31] has focussed on ways to integrate the transaction processing algorithms of disparate DBMSs to achieve some correctness criteria such as global serializability [3] or an approximation of it such as quasi serializability [17] Some propose that changes be made to the local database system [19, ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACM-SIGMOD 1988 International Conference on Management of Data, pages 135-- 142, 1988.

....Database consistency is traditionally ensured by requiring that the concurrent execution of transactions be serializable #that is, equivalent to a non concurrent execution##Papadimitriou 1986#. The problem of ensuring global serializabilityin an MDBS environment has been studied extensively #Breitbart and Silberschatz 1988; Breitbart et al. 1990; Georgakopoulos et al. 1991; Batra et al. 1992; Du et al. 1989; Mehrotra et al. 1992; Pu 1988; Raz 1992#. A necessary condition for # 3 maintaining global serializability is that all global transactions that access data at multiple DBMSs are serialized in the same order at ....

....in higher concurrency without violating database consistency. 7. RELATED AND PREVIOUS WORK Research on concurrency control in MDBSs has been done along two complementary directions. Signi#cantwork has gone into developing techniques to ensure global serializability. These techniques include #Breitbart and Silberschatz 1988; Breitbart et al. 1990; Georgakopoulos et al. 1991; Batra et al. 1992; Du et al. 1989; Mehrotra et al. 1992; Pu 1988; Raz 1992; Breitbart et al. 1991; Breitbart and Silberschatz 1992#. As mentioned previously, since the MDBS software is unaware of the local transactions execution, schemes that ....

Breitbart, Y. and Silberschatz, A. 1988. Multidatabaseupdate issues. In Proceedings of ACM-SIGMOD 1988 International Conference on Management of Data, Chicago #1988#, pp. 135#141.

....serialization order at all sites on which they execute. To assure that global serializability is not violated, local histories must be validated by the workflow management system. The problems of determining local serialization order were discussed in the literature on multidatabase transactions [5]. The main difficulty is caused by the possibility of indirect conflicts that may be caused by the local tasks executed outside of global workflows. A possible mechanism for detection of inter workflow conflicts may be based on the ticket concept proposed in [24] Global commitment. We say that a ....

Y. Breitbart and A. Silberschatz. Multidatabase Update Issues. In Proceedings of ACM SIGMOD International Conference on Management of Data, June 1988.

....transaction management is handled at both the global and local levels. As a confederation of pre existing local Current address: MCC, 3500 West Balcones Center dr, Austin, TX 78759. 1 databases, the overriding concern of any HDDBS must be the preservation of local autonomy [Lit86, GMK88, BS88, Pu88, Vei90, VW92] This is accomplished through the superimposition of a global transaction manager (GTM) upon a set of local database systems (LDBSs) Global transactions are submitted to the global transaction manager, where they are parsed into a set of global subtransactions to be ....

....In this section, we will discuss various inconsistent scenarios that may arise when compensation or retrial are allowed. These observations are important input for the establishment of a suitable global concurrency control correctness criterion. 3. 1 Global Serializability Global serializability [BS88, BGMS92] is an accepted correctness criterion for the execution of (non exible) global and local transactions in the HDDBS environment. A global schedule S is globally serializable if the committed projection from S of both global transactions in the HDDBS environment and transactions that run ....

Y. Breitbart and A. Silberschatz. Multidatabase Update Issues. In Proceedings of the ACM SIGMOD Conference on Management of Data, pages 135-142, Chicago, IL, June 1988. 24

....transaction management is handled at both the global and local levels. As a confederation of pre existing local Current address: MCC, 3500 West Balcones Center dr, Austin, TX 78759. 1 databases, the overriding concern of any HDDBS must be the preservation of local autonomy [Lit86, GMK88, BS88, Pu88, Vei90, VW92] This is accomplished through the superimposition of a global transaction manager (GTM) upon a set of local database systems (LDBSs) Global transactions are submitted to the global transaction manager, where they are parsed into a set of global subtransactions to be ....

....In this section, we will discuss various inconsistent scenarios that may arise when compensation or retrial are allowed. These observations are important input for the establishment of a suitable global concurrency control correctness criterion. 3. 1 Global Serializability Global serializability [BS88, BGMS92] is an accepted correctness criterion for the execution of (non flexible) global and local transactions in the HDDBS environment. A global schedule S is globally serializable if the committed projection from S of both global transactions in the HDDBS environment and transactions that run ....

Y. Breitbart and A. Silberschatz. Multidatabase Update Issues. In Proceedings of the ACM SIGMOD Conference on Management of Data, pages 135--142, Chicago, IL, June 1988.

....across the various resources. An assumption made often is that every site that maintains data runs a local transaction manager that has to be coordinated with various other managers involved in the realization of a transaction. Most of the work so far has relied on conventional short transactions [5, 25, 16]. This type of processing introduces several limitations. Multidatabase transactions often result in long lived actions which may lock local database resources for unacceptably long periods of time creating delays. A number of solutions have been suggested in the research work conducted on the ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. Procs. ACM SIGMOD Int'l Conference on Management of Data, June 1988.

.... particular ordering of global transactions at a local DBMS is by controlling the execution of certain operations belonging to global subtransactions (referred to as serialization events [ED90] In such an environment, adopting serializability 1 as the notion of correctness, as is done in [Pu88, BS88, ED90, BST90, BGRS91, PRR91, SKS91, GRS91, MRB 92, Raz92] could result in a low degree of concurrency and adversely affect the performance of the system. Furthermore, in most MDBS environments, due to the autonomous nature of of local DBMSs, integrity constraints between data items belonging ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACMSIGMOD 1988 International Conference on Management of Data, Chicago, pages 135--141, 1988.

....see [8, 17] This sacrifices autonomy, necessitates the costly development of a large amount of system software, and may also require the modification of existing applications. The second approach is to retain local autonomy and make minimal changes, if any, to the existing DBMS 3 software [3, 4, 15]. While this is more cost effective than the first approach in terms of the development of the integrated system, from the designer s viewpoint it is more difficult to accomplish. In fact, this approach often severely restricts the types of transactions that may execute in the system. For example, ....

....cost effective than the first approach in terms of the development of the integrated system, from the designer s viewpoint it is more difficult to accomplish. In fact, this approach often severely restricts the types of transactions that may execute in the system. For example, the restriction in [3] permits any pair of concurrently executing global transactions to have at most one site in common. The work in [15] proposes a new concurrency control mechanism that ensures serializability and freedom from deadlocks. However, the transactions that may execute in the system are of a restricted ....

Breitbart, Y. and Silberschatz, A. 1988. Multidatabase Update Issues. Proc. ACM-SIGMOD International Conference on Management of Data (Jun).

....over its data and its local transactions. Over the past decade, substantial research has been done to identify mechanisms for effectively dealing with the problems that arise due to the heterogeneity and the autonomy of the local systems (e.g. BST90, WV90, MRB 92b, Pu88, ED90, MRB 92a, BS88] This research has resulted in transaction management algorithms that ensure correctness without sacrificing the autonomy of the individual systems. Most of the proposed approaches have, however, considered an MDBS as a single monolithic system which executes on top of the existing local DBMSs ....

....k . Note that if there exists a domain D 2 Delta such that for each DB k , k = 1; 2; m, parent(D; DB k ) then our MDBS architecture reduces to a single monolithic system. In this case, the existing solutions for transaction management developed for such systems in [MRB 92a, ED90, BS88, BST90] can be used by the domain manager for D to control the concurrent execution of the transactions. Similarly, if we were to restrict Delta such that for all domains D i ; D j 2 Delta, if child(D i ; D j ) then for all D k 6= D j , child(D i ; D k ) then our MDBS architecture reduces ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACMSIGMOD 1988 International Conference on Management of Data, Chicago, pages 135-- 141, 1988.

....result in a loss of control by the local DBMS over its data and its local transactions. Over the past decade, signi#cant research has been done to identify mechanisms for e#ectively dealing with the problems that arise due to the heterogeneity and the autonomy of the local systems, e.g. Pu 1988; Breitbart et al. 1988, 1990; Wolski et al. 1990; Mehrotra et al. 1992a, 1992b; Elmagarmid et al. 1990; Batra et al. 1992. This research has resulted in transaction management algorithms that ensure correctness without sacri#cing the autonomy of the individual systems. A large number of these proposed solutions ....

....et al. 1987; Papadimitriou 1986; Gray et al. 1993 motivate the need for serializability using the preservation of data integrity constraints as the theoretical basis of correctness. Another signi#cant body of research exists on mechanisms to ensure serializability in MDBS environments Breitbart et al. 1988, 1990; Wolski et al. 1990; Pu 1988; Mehrotra et al. 1992a; Elmagarmid et al. 1990. One of the #rst signi#cant approaches developed was in Pu 1988 where a notion of o element was introduced. An o element corresponding to a transaction is one of its operations that satis#es the following ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACM-SIGMOD 1988 International Conference on Management of Data, Chicago, pages 135#141, 1988.

....in a loss of control by the local DBMS over its data and its local transactions. Over the past decade, significant research has been done to identify mechanisms for effectively dealing with the problems that arise due to the heterogeneity and the autonomy of the local systems, e.g. Pu 1988; Breitbart et al. 1988, 1990; Wolski et al. 1990; Mehrotra et al. 1992a, 1992b; Elmagarmid et al. 1990; Batra et al. 1992. This research has resulted in transaction management algorithms that ensure correctness without sacrificing the autonomy of the individual systems. A large number of these proposed ....

....et al. 1987; Papadimitriou 1986; Gray et al. 1993 motivate the need for serializability using the preservation of data integrity constraints as the theoretical basis of correctness. Another significant body of research exists on mechanisms to ensure serializability in MDBS environments Breitbart et al. 1988, 1990; Wolski et al. 1990; Pu 1988; Mehrotra et al. 1992a; Elmagarmid et al. 1990. One of the first significant approaches developed was in Pu 1988 where a notion of o element was introduced. An o element corresponding to a transaction is one of its operations that satisfies the following ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACM-SIGMOD 1988 International Conference on Management of Data, Chicago, pages 135--141, 1988.

No context found.

Y. Breitbart and A. Silberschatz, "Multidatabase Update Issues," Proceedings of ACM SIGMOD Conference, 1988.

....we study the tradeoffs between the complexities of the various schemes and the degree of concurrency provided by each of them. 1 Introduction The problem of transaction management in a multidatabase system (MDBS) has received considerable attention from the database community in recent years [BS88, Pu88, BST90, ED90, GRS91, MRKS91, SKS91] The basic problem is to design an effective and efficient transaction management scheme that allows users to access and update data items managed by pre existing This material is based in part upon work supported by NSF grants IRI 8805215 and IRI 9003341 ....

....local applications make calls to the local DBMS interfaces, and thus the GTM, which is built on top of the local DBMSs, is not involved in the execution of the local transactions. Various schemes to ensure global serializability in an MDBS environment have been previously proposed (e.g. BS88, Pu88, ED90, GRS91] These proposed schemes have been ad hoc in nature, and no analysis of their performance, the degree of concurrency provided by them, or their complexity has been made. In this paper, we provide a unifying framework for the study and development of concurrency control schemes ....

[Article contains additional citation context not shown here]

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACM-SIGMOD 1988 International Conference on Management of Data, Chicago, pages 135--141, 1988.

....failures such that atomicity of the global transactions is ensured. Problems in Ensuring Serializability: The problem of ensuring global serializability consists of ensuring serializability of the global schedule under the assumption that local schedules at each local DBMS are serializable. In [Breitbart and Silberschatz 1988], it is claimed that global serializability is ensured if there exists a total order defined over global transactions that is consistent with the serialization order of global transactions at each of the local DBMSs. Indeed, it can be shown that the above condition is both necessary and sufficient ....

....The timeout approach is even more attractive for MDBSs since unlike traditional distributed DBMSs, local DBMSs may not possess the capability of exchange information about their wait for graphs. Theoretically, this problem can be overcome and techniques for detecting deadlocks are discussed in [Breitbart and Silberschatz 1988]. These techniques are quite pessimistic and assume that if two transactions are concurrently active at the same local DBMS, then one of them is waiting for the other. As a result, a large number of false deadlocks are detected. Even timeout based mechanisms may not be simple to implement in MDBS ....

[Article contains additional citation context not shown here]

Breitbart, Y. and Silberschatz, A. 1988. Multidatabase update issues. In Proceedings of ACM-SIGMOD 1988 International Conference on Management of Data, Chicago (1988), pp. 135--141.

....environment is difficult. This is due to the fact that the local transactions execute outside the control of the GTM, and the local DBMSs may follow different concurrency control schemes. Schemes for ensuring global serializability in a failure free MDBS environment have been proposed in [BS88, ED90, BGRS91, GRS91, MRB 92a] In an MDBS environment in which failures may occur, ensuring global serializability is further complicated due to the execution autonomy of the underlying local DBMSs. The problem of developing fault tolerant schemes for MDBS environments has been addressed in ....

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACMSIGMOD 1988 International Conference on Management of Data, Chicago, pages 135-- 141, 1988.

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Y. Breitbart and A. Silberschatz, `Multidatabase update issues', in Proc. ACM SIGMOD Int. Conf. on Management of Data, 1988.

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Y. Breitbart and A. Silberschatz, "Multidatabase Update Issues," Proceedings of ACM

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Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACM-SIGMOD 1988 International Conference on Management of Data, Chicago, pages 135--141, 1988.

No context found.

Y. Breitbart and A. Silberschatz. Multidatabase update issues. In Proceedings of ACMSIGMOD 1988 International Conference on Management of Data, Chicago, pages 135-- 141, 1988.

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Y. Breitbart and A. Silberschatz, "Multidatabase Update Issues," Proc. of 1988 SIGMOD Conf., Chicago, IL, June 1988, pp. 135-142.

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