W. Kim and J. Srivastava. Enhancing real-time DBMS performance with multiversion data and priority based disk scheduling. In Proc. of Real-Time Systems Symposium, pages 222--231, 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

.... algorithm such as the Shortest Seek Time First or SCAN (Elevator) orders the sequence of IO requests to minimize the average disk head seek time [16] On the other hand, the disk scheduler in a RTDBS primarily concerns the timing constraints of transactions in processing data access requests [3, 11, 13, 37]. As discussed in [49] one important issue in scheduling the IO requests of a RTDB transaction is the assignment of individual deadlines to the requests on the basis of the transaction deadline. This issue has not been addressed explicitly by the recent work performed on IO scheduling. We ....

....constraint; i.e. it is assigned the lowest priority. The rationale behind this policy is that giving high priority to a write does not enhance the performance directly since the transaction that issued the write has already committed. An extension to this policy was provided by Kim and Srivastava [37] on the basis of the priority inheritance rule. Assuming that a write lock is held until after the modified data item is copied into the database, if a transaction is waiting for the release of a write lock, the write request inherits the priority of the waiting transaction to activate the ....

[Article contains additional citation context not shown here]

W. Kim, J. Srivastava `Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling', Proceedings of the 12th Real-Time Systems Symposium, 1991, pp.222-231. 27

....Son et al. examined a priority driven locking protocol which decomposes the problem of concurrency control into two subproblems, namely read write synchronization and write write synchronization, and integrates the solutions to two subproblems considering transaction priorities. Kim and Srivastava [26] proposed new multiversion concurrency control algorithms to increase concurrency in RTDBSs. Ozsoyo glu et al. 30] introduced new techniques to process database queries within fixed time quotas. Different degrees of accuracy of the responses to the queries can be achieved by using those ....

W.Kim, J.Srivastava, "Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling", 12th Real-Time Systems Symposium, 1991, pp.222-231.

....2PL s long and unpredictable blocking times damage its appeal for real time environments, where the primary performance criterion is meeting time constraints and not just preserving consistency requirements. Over the last few years, several alternatives to 2PL for RTDBMS have been explored [18, 14, 13, 16, 17, 20, 30]. In a recent study [5] we proposed a categorically different approach to concurrency control for RTDBMS. Our approach relies on the use of redundant computation to start on alternative schedules, once conflicts that threaten the consistency of the database are detected. These alternative ....

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium, December 1991.

....version of this paper appears in the proceedings of the ACM SIGMOD Conference, May 1993. 1. Introduction Database management systems (DBMS) are faced with increasingly demanding performance objectives. These objectives could be time constraint requirements, as in real time database systems [SIGM88, Abbo88, Huan89, Hari90, Kort90, Kim91, RTS92], or administration defined performance goals as in goal oriented database systems [Ferg93, Brow93] Traditional first come first serve or round robin scheduling policies are no longer adequate to meet such objectives; a DBMS has to prioritize transactions that are competing for system resources ....

W. Kim, J. Srivastava, "Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling", Proc. of the 1991 IEEE 12th Real-Time Systems Symposium (RTSS).

....finishes successfully, the result is known. Thus several versions of the computation can be run, with different time bounds, guaranteeing an upper bound on the time to produce some result. Mena [Mena82] has classified concurrency control algorithms into two classes: optimistic algorithms (e.g. [Hari90b, Hari90a, Huan90, Kim91, Lin90, Son92]) and pessimistic algorithms (e.g. Abbo88, Stan88, Huan90, Sha91] Bestavros has proposed (in [Best92] a new approach, Speculative Concurrency Control (SCC) which incorporates redundant computation into concurrency control algorithms. Speculative concurrency control redundantly executes the ....

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium, December 1991.

.... Son et al. examined a priority driven locking protocol which decomposes the problem of concurrency control into two subproblems, namely read write synchronization and write write synchronization, and integrates the solutions to two subproblems considering transaction priorities [Son et al. 1992] In [Kim and Srivastava 1991], new multiversion concurrency control algorithms were proposed to increase concurrency in RTDBSs. In [Ulusoy and Belford 1993] we described several real time concurrency control protocols and reported their relative performance in a single site RTDBS. The remainder of the paper is organized as ....

W. Kim, J. Srivastava, Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling, 12th Real-Time Systems Symposium, 222231.

....[Gra92] on RTDBS of which the most active is developing transaction scheduling algorithms for soft and firm real time transactions. The scheduler of a RTDBS is responsible for assigning priorities [HJC93, HSRT91, LL73, SZ88] and resolving access conflicts among transactions based on priorities [AGM89, BMH89, HCL90b, KS91, KM92, KM93, LS93, LS90, Sha88]. Among them several approaches [AGM88, HCL90b, HSRT91, LS93, LLH95] are specifically studied for firm RTDBS and several OCC variants have been proposed, and showed the problems of 2PL HP for firm deadline transactions. However, 2PL and 2PL HP yield better performance than OCC or OCC variants for ....

Woosaeng Kim and Jaideep Srivastava. Enhancing real-time DBMS performance with multiversion data and priority based disk scheduling. In Proceedings of Real-Time Systems Symposium, pages 222--231. IEEE, 1991.

....transactions that span multiple database operations. We do not believe that such transactions can be supported in hard real time systems without sacrificing serializability. In the future we may investigate providing limited support for more complex transactions, perhaps using data versioning [39], but we have not yet developed a model of such transactions or tried to implement one within MDARTS. With the current MDARTS transaction model, it is possible to guarantee transaction times while supporting atomicity, consistency, isolation, and serializability. The processing required to perform ....

....concurrency control techniques described in the literature to MDARTS. To implement concurrency control in MDARTS we propose the following principles. Our current implementation reflects all of these ideas except data versioning. Avoid unnecessary locking. When possible, use data versioning [39, 79] or multiple data copies [90] to permit concurrent read and write operations without locking. Match locking granularity with data semantics. This ensures that locking does not unnecessarily restrict concurrency. Sha et al. 66] Badrinath and Ramamritham [6] and Son [79] all propose locking only ....

W. Kim and J. Srivastava, "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling," in Proc. Real-Time Systems Symposium, pp. 222--231, December 1991.

.... transaction priorities [74, 88] ii) forcing the validating transaction into a wait state until the conflicts are resolved [74] or (iii) using dynamic adjustment of the serialization order [124] Other concurrency control techniques for real time databases include using multiple copies of data [119, 213], and hybrid protocols that combine lock based, timestamp ordering based, and optimistic concurrency control techniques [195] Comparative evaluations of most of these techniques are not yet available. The discussion in this section so far has assumed the use of flat transactions. When a ....

....priority as they are related to transactions that have completed their executions. Read requests are then assigned priorities on the basis of their deadlines. Priority inheritance can be added into this scheme for write requests that block other high priority transactions (due to write locks) [119]. SCAN algorithms can also be revised using the knowledge of prioritized groups of disk requests [33] Another approach tries to balance time constraints of disk requests and the overall I O performance in terms of the average seek time [37] 7 Conclusions and Future Work Temporal database ....

Kim, W., and Srivastava, J., "Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling," in Proceedings of the 12th Real-Time Systems Symposium, pp. 222--231, 1991.

....on isochronous multimedia data necessitate deadlines by which the data must be fetched. Careful consideration of these factors is required for consistent and efficient management of disk resources. A class of new disk scheduling algorithms were developed to deal with these additional constraints[18, 25, 19, 7, 3, 14, 6]. A common feature of these new scheduling algorithms is that the additional constraints are satisfied first. Seek optimization is considered secondary and performed whenever possible. While these scheduling algorithms work well in some cases, disk utilization can be very low as seek optimization ....

....superior to either SCAN or SSTF. 2.2 New Disk Scheduling Algorithms The additional requirements introduced by applications, such as digital multimedia and database systems, make traditional disk scheduling algorithms described above inappropriate. Many new scheduling algorithms have been developed[3, 17, 2, 14, 6, 21]. 2.2.1 Multimedia Specific Algorithms EDF The Earliest Deadline First algorithm is an analog of FCFS. Disk requests are ordered according to deadlines and the request with the earliest deadline is serviced first. EDF has similar expected seek time as FCFS, since no positional information is used ....

W. Kim and J. Srivastava. Enhancing real-time DBMS performance with multiversion data and priority based disk scheduling. In Proc. of the 12th Real-Time Systems Symposium, pages 222--231, 1991.

....2 Previous Work In addition to the approaches taken for real time systems, there is a large body of work on RTDBS that can be summarized as follows: ffl Priority scheduling and concurrency control 1. 2PL HP, 2PL WP, 2PL CR [AGM89] 2. Optimistic concurrency control (OCC) HCL90b] 3. Multiversion [KS91] 4. Mixed Integrated concurrency control [LS90] 5. Semantics and correctness [KM92] ffl Buffer management [CJL89, RMM90] ffl IO scheduling [AGM89, KS91] In this paper, we focus on priority assignment of concurrent transactions. Concurrency control based real time database (time critical ....

....Priority scheduling and concurrency control 1. 2PL HP, 2PL WP, 2PL CR [AGM89] 2. Optimistic concurrency control (OCC) HCL90b] 3. Multiversion [KS91] 4. Mixed Integrated concurrency control [LS90] 5. Semantics and correctness [KM92] ffl Buffer management [CJL89, RMM90] ffl IO scheduling [AGM89, KS91] In this paper, we focus on priority assignment of concurrent transactions. Concurrency control based real time database (time critical database) scheduling algorithms combine various properties of time critical schedulers with properties of concurrency control algorithms [AGM92, BMH89, CBB ....

[Article contains additional citation context not shown here]

Woosaeng Kim and Jaideep Srivastava. Enhancing real-time dbms performance with multiversion data and priority based disk scheduling. In Proceedings of Real-Time Systems Symposium, pages 222--231. IEEE, 1991.

....order, the conflicts are resolved based on their priorities. In addition, several combinations of locking based, optimistic and timestampbased protocols have been proposed but require quantitative evaluation [34] Exploiting multiple versions of data for enhanced performance has been addressed in [29]. Multiple versions can reduce conflicts over data. However, if data must have temporal validity, old versions which are outdated must be discarded. Also, when choosing versions of related data, their relative consistency requirements must be taken into account: consider a transaction that uses ....

W. Kim and J. Srivastava, "Enhancing Real-Time DBMS Performance with Multiversion Data and Priority-Based Disk Scheduling", Proceedings of the Real-Time Systems Symposium, Dec 1991, pp. 222-231.

....blocking times that damage its appeal for real time environments, where the primary performance criterion is meeting time constraints and not just preserving consistency requirements. Over the last few years, several alternatives to 2PL for RTDBMS have been explored, proposed, and investigated [Kort90, Hari90b, Hari90a, Huan91, Kim91, Lin90, Son92]. In a recent study [Best92b] Bestavros proposed a categorically different approach to concurrency control for RTDBMS. His approach relies on the use of redundant computation to start on alternative schedules, once conflicts that threaten the consistency of the database are detected. These ....

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium, December 1991.

....and unpredictable blocking times that damage its appeal for real time environments, where the primary performance criterion is meeting time constraints and not just preserving consistency requirements. Over the last few years, several alternatives to 2PL for RTDBMS have been proposed and explored [Kort90, Hari90a, Huan91, Kim91, Lin90, Son92]. Among these alternatives, the Optimistic Concurrency Control algorithm with Broadcast Commit (OCC BC) Mena82, Robi82] has been singled out as an attractive protocol for RTDBMS [Hari90b] In this paper, OCC BC is used as a representative of OCC based algorithms. In a recent study [Best92a] ....

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium, December 1991.

....(such as the possibility of deadlocks and or long, unpredictable blocking times) which damage its appeal for RTDBMS, where in addition to preserving database consistency, strict timing constraints must be honored. Recently, some alternatives to 2PL for real time systems have been proposed [Hari90b, Hari90a, Huan91, Kim91, Lin90, Son92]. A class of these concurrency control protocols is based on OCC, which due to its potential for a high degree of concurrency was expected to perform better than 2PL when integrated with priority driven CPU scheduling in real time database systems. In addition, the non blocking and deadlock free ....

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium, December 1991.

....(such as the possibility of deadlocks and or long, unpredictable blocking times) which damage its appeal for RTDBMS, where in addition to preserving database consistency, strict timing constraints must be honored. Recently, some alternatives to 2PL for real time systems have been proposed [Hari90b, Hari90a, Huan91, Kim91, Lin90, Son92]. A class of these concurrency control protocols is based on OCC, which due to its potential for a high degree of concurrency was expected to perform better than 2PL when integrated with priority driven CPU scheduling in real time database systems. In addition, the non blocking and deadlock free ....

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium, December 1991.

.... Lin 1990] David et al. 1994] DiPippo Wolfe 1993] Goyal et al. 1995] Haritsa et al. 1990a] Haritsa et al. 1990b] Haritsa et al. 1992] Haritsa et al. 1993] Hong et al. 1993] Huang et al. 1989] Huang et al. 1991a] Huang et al. 1991b] Huang et al. 1992] Kim et al. 1990] [Kim Srivastava 1991], Kuo Mok 1992] Lam et al. 1995] Lee Son 1993] Lee Son 1994] Lee Son 1995] Lin Son 1990] Sha et al. 1988] Sha et al. 1990] Sha et al. 1991] Son 1989] Son Chang 1990] Son Lee 1990] Son 1990] Son et al. 1992a] Son et al. 1992b] Son et al. 1992d] Son et ....

....scheduler in a real time database system primarily concerns the timing constraints of transactions in processing their data access requests. Disk scheduling algorithms developed for real time database systems are presented in: Abbott Garcia Molina 1990] Carey et al. 1989] Chen et al. 1991] [Kim Srivastava 1991]. 2.5 Memory Management A number of algorithms regarding the allocation management of memory buffers have also been proposed to be used in real time database systems. The basic consideration in those algorithms is again the priorities of processed transactions. In the following papers, new ....

W. Kim, J. Srivastava `Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling', Proceedings of the 12th Real-Time Systems Symposium, 1991, pp.222-231.

....lower priority transactions, while the lower priority transaction may not have to be aborted even in case of conflicting with the higher priority transactions. Multiversion concurrency control algorithms have been tailored to real time concurrency control by using priorities of transactions. In [9] they developed real time multiversion 2PL algorithms that do not require a prior knowledge of running transactions. The benefit of allowing multiple versions on data is that since the write operation produces a new data version, there is no conflict among the write operations. As a result, the ....

....However, there are several problems in introducing MV2PL into real time database processing. Since a MV2PL scheduler resolves data conflicts by blocking a transaction which requests a conflicting operation, it suffers from priority inversion problem by which transactions may miss their deadlines[9]. In what follows, we introduce the basic concept of MV2PL and discuss its problems as real time concurrency control. There are three kinds of locks in MV2PL : read locks, write locks and certify locks. Since a write operation on a data object x produces a new data version on x, concurrent write ....

W. S. Kim and J. Srivastava. Enhancing real-time dbms performance with multiversion data and priority based disk scheduling. In Prooceedings of the 12th Real-Time Systems Symposium, pages 222--231, December 1991.

....requester should wait for V lock holder to release V lock. On the other hand, lock conflicts during the validation phase are resolved by one of several mechanisms such as commit, priority abort and priority wait. There has been a work that adopts multiversion to real time concurrency control. In [7] they proposed real time multiversion 2PL that does not require a prior knowledge of running transactions. While the multiversion 2PL scheduler can have more freedom than the single version scheduler due to no conflict among the write operations, this algorithm tends to delay aborts of the ....

W. S. Kim and J. Srivastava. Enhancing real-time dbms performance with multiversion data and priority based disk scheduling. In Prooceedings of the 12th Real-Time Systems Symposium, pages 222--231, December 1991.

No context found.

W. Kim and J. Srivastava. Enhancing real-time DBMS performance with multiversion data and priority based disk scheduling. In Proc. of Real-Time Systems Symposium, pages 222--231, 1991.

No context found.

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium, December 1991.

No context found.

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium,December 1991.

No context found.

Woosaeng Kim and Jaideep Srivastava. "Enhancing real-time dbms performance with multiversion data and priority based disk scheduling." In Prooceedings of the 12th Real-Time Systems Symposium,December 1991.

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W. Kim and J. Srivastava, "Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling", Proceedings of Real-Time Systems Symposium, pp. 222-231, 1991. 68

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W. Kim, J. Srivastava, "Enhancing Real-Time DBMS Performance with Multiversion Data and Priority Based Disk Scheduling", Proc. of the 1991 IEEE 12th Real-Time Systems Symposium (RTSS).

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