J. Lee and S.H. Son, "Performance of Concurrency Control Algorithms for Real-Time Database Systems," Performance of Concurrency Control Mechanisms in Centralized Database Systems, Prentice Hall, 1996.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....data contention. Considerable research has been devoted to designing concurrency control algorithms for RTDBSs and to evaluating their performance Most of these algorithms use serializability as correctness criteria and are based on one of the two basic concurrency control mechanisms: 2PL [4, 6, 12, 13, 16, 21] or optimistic concurrency control (OCC) 9, 7, 3, 2, 13, 10, 11] However, This work is partially funded by Nokia Telecommunications, Solid Information Technology Ltd. and the National Technology Agency Finland. 2PL has some inherent problems such as the possibility of deadlocks as well as ....

.... to designing concurrency control algorithms for RTDBSs and to evaluating their performance Most of these algorithms use serializability as correctness criteria and are based on one of the two basic concurrency control mechanisms: 2PL [4, 6, 12, 13, 16, 21] or optimistic concurrency control (OCC) [9, 7, 3, 2, 13, 10, 11]. However, This work is partially funded by Nokia Telecommunications, Solid Information Technology Ltd. and the National Technology Agency Finland. 2PL has some inherent problems such as the possibility of deadlocks as well as long and unpredictable blocking times. These problems appear to be ....

J. Lee and S. H. Son. Performance of concurrency control algorithms for real-time database systems. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems, pages 429--460. 1996.

....requirements [27] Optimistic concurrency control methods [8, 15] are especially attractive for real time database systems because they are non blocking and deadlock free. Therefore, in recent years, numerous optimistic concurrency control methods have been proposed for real time databases (e.g. [16, 20, 21]) Although optimistic approaches have been shown to be better than locking methods for real time database systems [9, 10] they have the problem of unnecessary restarts and heavy restart overhead. This is due to the late conflict detection that increases the restart overhead since some ....

....The feasibility of the proposed method is evaluated in a real time database system for telecommunications. The method presented in this paper is related to two previously presented optimistic concurrency control methods, namely OCC TI (Optimistic Concurrency Control with Timestamp Intervals) [20] and OCC DA [16, 17] Optimistic Concurrency Control with Dynamic Adjustment) OCC TI is based on the forward validation scheme. The number of transaction restarts is reduced by using dynamic adjustment of the serialization order. OCC DA is based on the forward validation scheme [8] and on the use ....

[Article contains additional citation context not shown here]

J. Lee and S. H. Son. Performance of concurrency control algorithms for real-time database systems. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems, pages 429--460. Prentice-Hall, 1996.

....data contention. Considerable research has been devoted to designing concurrency control algorithms for RTDBSs and to evaluating their performance Most of these algorithms use serializability as correctness criterion and are based on one of the two basic concurrency control mechanisms: 2PL [4, 6, 12, 13, 16, 19] or optimistic concurrency control (OCC) 9, 7, 3, 2, 13, 10, 11] However, 2PL has some inherent problems such as the possibility of deadlocks as well as long and unpredictable blocking times. These problems appear to be serious in real time transaction processing since real time transactions ....

.... to designing concurrency control algorithms for RTDBSs and to evaluating their performance Most of these algorithms use serializability as correctness criterion and are based on one of the two basic concurrency control mechanisms: 2PL [4, 6, 12, 13, 16, 19] or optimistic concurrency control (OCC) [9, 7, 3, 2, 13, 10, 11]. However, 2PL has some inherent problems such as the possibility of deadlocks as well as long and unpredictable blocking times. These problems appear to be serious in real time transaction processing since real time transactions need to meet their This work is partially funded by Nokia ....

J. Lee and S. H. Son. Performance of concurrency control algorithms for real-time database systems. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems, pages 429--460, 1996.

....by exploiting and extending the capabilities of priority insensitive algorithms. The protocol presented in this paper is related to two previously presented optimistic concurrency control protocols, namely OCC TI and OCC DA. OCC TI (Optimistic Concurrency Control with Timestamp Intervals) [23] is based on the forward validation scheme. The number of transaction restarts is reduced by using dynamic adjustment of the serialization order. OCC DA (Optimistic Concurrency Control with Dynamic Adjustment) 20, 21] is also based on the forward validation scheme and on the use of dynamic ....

....[25] algorithm. 3. OCC DATI In this section, we briefly present our earlier optimistic concurrency control protocol named OCCDATI (Optimistic Concurrency Control with Dynamic Adjustment of Serialization Order) 25] OCCDATI uses similar dynamic adjustment of the serialization order as in OCC TI [23]. Unlike the OCCTI protocol, all checking is performed at the validation phase of each transaction. There is no need to check for conflicts while a transaction is still in its read phase. As the conflict resolution between the transactions in OCC DATI is delayed until a transaction is near ....

Lee, J. and Son, S. H. (1996). Performance of concurrency control algorithms for real-time database systems. In Kumar, V., editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems, pages 429--460. Prentice-Hall.

....time or throughput. Scheduling of transactions is driven by priority considerations rather than fairness considerations. Given these significant differences, considerable research has been recently devoted to designing concurrency control algorithms for RTDBSs and to evaluating their performance [AGM88, HCL90b, HSTR89, HSRT91, LLH95a, LLH95b, LSH97, LS96, KLR97, MN82]. Most of these algorithms are based on one of the two basic concurrency control mechanisms: locking [EGLT76] or optimistic concurrency control (OCC) KR81] Some of them use priority information in the resolution of conflicts, that is, conflicts are resolved in favor of the higher priority ....

....conclusion of the paper is presented in 2 Section 4. 2 A New Real Time OCC Protocol OCC DATI is based on forward validation [Har84] The number of transaction restarts is reduced by dynamic adjustment of serialization order which is supported with timestamp intervals. Unlike the OCC TI protocol [LS96, KLR97], all checking is performed at the validation phase of each transaction. There is no need to check for conflicts while a transaction is still in its read phase. In OCC DATI, when a transaction enters the validation phase, it s serialization order relative to its conflicting transactions will be ....

Y. Lee and S. Son. Performance of concurrency control algorithms for real-time database systems. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems, pages 429--460. Prentice-Hall, 1996.

.... In this section we present an optimistic concurrency control protocol named OCC DATI [16] OCC DATI is based on forward validation [4] The number of transaction restarts is reduced by dynamic adjustment of the serialization order which is supported by similar timestamp intervals as in OCC TI [15]. Unlike the OCC TI protocol, all checking is performed at the validation phase of each transaction. There is no need to check for conflicts while a transaction is still in its read phase. As the conflict resolution between the transactions in OCC DATI is delayed until a transaction is near ....

J. Lee and S. H. Son. Performance of concurrency control algorithms for realtime database systems. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems, pages 429--460. Prentice-Hall, 1996.

....to make their deadlines first. If the transaction finally commits after waiting for some time, it causes all its conflicting transactions with lower priority to be restarted. This transaction restart problem becomes worse with the possibility of chained blocking, which may cause cascaded aborts [LS96] The WAIT 50 [HCL90a] algorithm is an extension of the OPT WAIT. It incorporates a wait control mechanism. This mechanism monitors transaction conflict states and dynamically decides when, and for how long, a low priority transaction should be made to wait for its conflicting higher priority ....

Y. Lee and S. Son. Performance of concurrency control algorithms for real-time database systems. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems, pages 429--460. Prentice-Hall, 1996.

....control protocol named OCC PDATI. OCC PDATI is based on forward validation [10] and our earlier optimistic protocol OCC DATI [26] The number of transaction restarts is reduced by dynamic adjustment of the serialization order which is supported by similar timestamp intervals as in OCC TI [25]. Unlike the OCC TI protocol, all checking is performed at the validation phase of each transaction. There is no need to check for conflicts while a transaction is still in its read phase. As the conflict resolution between the transactions in OCC PDATI is delayed until a transaction is near ....

J. Lee and S. H. Son. Performance of concurrency control algorithms for real-time database systems. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems, pages 429--460. Prentice-Hall, 1996.

....foundation for more complex soft deadline systems [4] The most important problem faced in RTDBSs concerns the degradation of system performance due to aborts and restarts of transactions. These restarts are caused by concurrency control protocols trying to resolve conflicts between transactions [5], 6] The objective of this Ph.D. thesis is to present new, more efficient concurrency control algorithms for firm deadline RTDBSs. The analysis of currently used methods allows to propose two new research directions: dynamic serialization adjustment, partial abort. The former direction ....

Lee, J., and Son, S.H., "Performance of Concurrency Control Algorithms for Real-Time Database Systems", Kumar V. (ed.) Performance of Concurrency Control Mechanisms in Centralized Database Systems, Prentice Hall, 1995.

....an easier approach to implement and to get statistically independent sample means compared to the batch means method. In addition, the replication method is known to give a reasonably proper statistical performance and has also been in the area of simulation study for concurrency control mechanism[8,9]. For the purpose of estimating the response time, suppose that we make n independent replications of a terminating simulation, where each replication is terminated by the same event and begins with the same initial conditions. The independence of replications can be accomplished by using ....

J. Lee, and S. Son, "Performance of Concurrency Control Algorithms for Real-Time Database Systems, Performance of Concurrency Control Mechanisms in Centralized Database Systems," Prentice Hall, pp. 429460, 1996.

....databases [18] Other extant surveys include those on temporal data models [97, 187] temporal query languages [38, 144, 189] and temporal access methods [168] In the last eight years, about 150 papers on real time databases have been published. There exist several surveys on this topic [126, 159, 213, 231]. Our emphasis is not on peripheral database research areas that may be useful to temporal and real time databases, such as main memory databases, active databases, or multi dimensional (spatial) databases. Instead, we hope to provide the reader with a general understanding of the major issues ....

....2.4 Time in Real Time Databases Current real time database research does not explicitly distinguish between the various time dimensions and the related time issues that are surveyed in this paper. However, close inspection reveals that real time databases use valid time and transaction time [30, 69, 126, 159, 190, 191, 213]. Valid time is used for data items that have immediate counterparts (external objects) in the real (physical) world. External events corresponding to value changes for these external objects are closely monitored, and write only transactions record them to the database. For example, programmable ....

Lee, J., and Son, S. H., "Performance of Concurrency Control Algorithms for Real-Time Database Systems," a chapter in Performance of Concurrency Control Mechanism in Centralized Database Systems, V. Kumar (ed), Prentice-Hall, 1995 (to appear).

....metric is used to determine how priority maintenance affects the real time performance. 4. Simulation model This section outlines the structure and details of our simulation model used to evaluate the performance of our concurrency control algorithms for real time database systems. Similar to [23], central to our simulation model is a single site main memory database system operating on multiple processors. The database is modeled as a collection of data pages in memory. The simulation consists of three main components: a Transaction Manager (TM) a CPU Manager (CM) and a Log Manager ....

Lee, J. and S.H. Son, "Performance of Concurrency Control Algorithms for Real-Time Database Systems," Performance of Concurrency Control Mechanisms in Centralized Database Systems, V. Kumar (ed.), Prentice Hall, 1996.

No context found.

J. Lee and S.H. Son, "Performance of Concurrency Control Algorithms for Real-Time Database Systems," Performance of Concurrency Control Mechanisms in Centralized Database Systems, Prentice Hall, 1996.

No context found.

J. Lee and S.H. Son, "Performance of Concurrency Control Algorithms for Real-Time Database Systems," Performance of Concurrency Control Mechanisms in Centralized Database Systems, Prentice Hall, 1996.

....size of database, etc. several long test runs are required to obtain acceptable confidence levels. Often, only a limited number of cases is simulated, which leads to incomplete and misleading results (as has been observed in [2] Some of the confusion (see e.g. the account given in [10]) is also caused by conclusions about properties based on mean values. As can be seen from Fig. 1, histograms with the same mean value may have very different profiles. The shape of such histograms becomes more important when we consider composite systems, where the interplay of the various ....

J. Lee and S.H. Son. Performance of Concurrency Control Algorithms for Real-Time Databases. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems. Prentice-Hall, 1996.

No context found.

J. Lee and S. H. Son. Performance of Concurrency Control Algorithms for Real-Time Database Systems. In V. Kumar, editor, Performance of Concurrency Control Mechanisms in Centralized Database Systems. Prentice Hall, 1996.

No context found.

J. Lee and S. H. Son, "Performance of Concurrency Control Algorithms for Real-Time Database Systems", Performance of Concurrency Mechanisms in Centralized Database Systems, V. Kumar (ed.), Prentice-Hall, 1996.

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