D. Shasha, E. Simon and P. Valdiruez, "Simple Rational Guidance for Chopping Up Transactions", Proc. of the 1992 ACM SIGMOD, June 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....results to other transactions so that more concurrency can be achieved by reducing isolation. In addition to that, by committing part of the work, the whole transaction will not be affected by failures. Kaiser et al. s approach to transaction partitioning is generalized by Shasha 149 et al. in [Sha 92] In their approach, a transaction is first divided into parts where each part includes an individual database access. Then, by considering these database accesses, a data dependency graph is constructed between the parts of the transaction to be partitioned and other transactions. By checking ....

....Gy : group set Tn ; Figure 8. 6: Algorithm for Finding the Data Groups of Transactions 161 the function ReviseGroups(T ) and it is O(e m) where e is the number of conflict edges among transaction T s parts and the other transactions, and m is the number of data accesses in transaction T [Sha 92] 8.5 Effects of Transaction Arrivals and Transaction Terminations Say, at one point of time, there are n Gamma 1 transactions running in the system. And a new transaction T n is introduced. Suppose one of n Gamma 1 transactions, T i , has two transaction parts, T i1 and T i2 , and data ....

D. Shasha, E. Simon and P. Valdiruez, "Simple Rational Guidance for Chopping Up Transactions", Proc. of the 1992 ACM SIGMOD, June 1992.

....of ADTs to define correctness, but there is a crucial difference in focus. We are interested in achieving more concurrency by expanding the set of correct execution histories such that some transactions need not be atomic. The second line is a set of papers on breaking transactions into steps [17], and in particular papers on semantic database concurrency control [1, 4, 16, 2, 5, 6, 10] Researchers have introduced the notions of transaction steps, countersteps, allowed vs. prohibited interleavings of steps, and implementations in locking environments. The focus is typically on ....

Dennis Shasha, Eric Simon, and Patrick Valduriez. Simple rational guidance for chopping up transactions. In Proceedings ACM SIGMOD International Conference on Management of Data, pages 298--307, San Diego, CA, June 1992.

....are given by the particular abstract data type. We relax the requirement that transactions in correct executions histories appear atomic. Many researchers have broken transactions into steps and developed semantics based correctness criteria for decompositions [AAS93, BR92, FO89, GM83, JM87] In [SSV92] correctness for chopped up transactions is defined such that any stepwise serial history is equivalent to a serial history. We disallow some stepwise serial histories based on semantic considerations. Some have weakened the notion of serializability. For example, quasi serializability defines ....

Dennis Shasha, Eric Simon, and Patrick Valduriez. Simple rational guidance for chopping up transactions. In Proceedings ACM SIGMOD International Conference on Management of Data, pages 298--307, San Diego, CA, June 1992.

....Rather than purely waiting for activity instances to request state change condition checkings, our dependency component might actively invoking activity instances that are involved in a specification change. There have been several work on transaction restructuring, like chopping transactions [23, 12] and split join transactions [20, 1] But they either are statically done at compile time, or only work on flat structures. In comparison, our work supports dynamic activity restructuring with transactional considerations, and work on structured activities. On one hand, our implementation method ....

D. Shasha, E. Simon, and P. Valduriez. Simple Rational Guidance for Chopping up Transactions. In Proceedings of 1992 SIGMOD International Conference on Management of Data, pages 298--307, May 1992.

....studied. The first direction is to design practical optimization techniques while preserving serializability as the correctness criterion. In this case, optimization is often achieved by using application semantics. A good example is chopping serializable transactions into shorter transactions [78]. This approach is usually referred to as semantics based optimization [32, 46, 74, 37, 49] The second direction to decrease data contention is to relax the restrictions on serializability. A good example is the design of epsilon transactions that operate under the semantics of epsilon ....

....the notion of conflict weights and non serializable conflict sets. The well extended divergence control theorem is proved by the ESR second lemma. 39 Chapter 3 Chopping Up Epsilon Transactions 3. 1 Introduction The first case is to study the relationship between ESR and chopping transactions [78], and search for the opportunities to integrate them for better performance. Epsilon serializability uses divergence control algorithms to allow more concurrency than classic serializability (SR) by permitting limited non serializable interleavings. Chopping up transactions [78] allows more ....

[Article contains additional citation context not shown here]

D. Shasha, E. Simon, and P. Valduriez. Simple rational guidance for chopping up transactions. In Proceedings of 1992 SIGMOD International Conference on Management of Data, pages 298--307, May 1992.

....by some serial schedule. Hence more flexibility, in the form of non serializable schedules, is permitted. In this paper we are interested in decomposing transactions into atomic, interleavable steps. Recent proposals along these lines whose goal is to preserve serializability are [17] 26] [32]. Most proposals, however, do not preserve serializability. A number of such proposals are described in [11] see also [4] An early paper that introduced issues related to decomposition using the spheres of control model is [9] A major issue that arises in systems that permit ....

D. Shasha, E. Simon, and P. Valduriez. Simple rational guidance for chopping up transactions. In Proc of 11th ACM SIGMOD/PODS Conf., June 1992.

....control plus demarcation protocol) using simulation. ffl Design of a general ESR system that includes both divergence control and consistency restoration. ffl Combination of ESR to other optimization techniques such as Escrow Method [12] Demarcation Protocol [3] and Transaction Chopping [24] ....

D. Shasha, E. Simon, and P. Valduriez. Simple rational guidance for chopping up transactions. In Proceedings of 1992 SIGMOD International Conference on Management of Data, pages 298--307, May 1992.

....A relatively serial schedule that is not relatively consistent relatively serializable relatively serial relatively consistent relatively atomic Figure 5: Relationships among the different correctness classes and write sets of transactions to eliminate the two phase locking rule. Shasha et al. SSV92] have proposed a chopping graph to refine user transactions such that only the smaller units of the transactions instead of the entire one need to be executed using strict two phase locking. 5 Discussion In this paper we have developed a theory for relaxing the atomicity of transactions to ....

D. Shasha, E. Simon, and P. Valduriez. Simple Rational Guidance for Chopping Up Transactions. In Proceedings of the 1992 ACM SIGMOD International Conference on Management of Data, pages 298--307, June 1992.

....if a given execution of transactions is correct. The acyclicity of this graph is both a necessary and sufficient condition for correctness. The main contribution of this theory is that unlike previous proposals [F O89] the recognition of correct executions can be done efficiently. Shasha et al. SSV92] recently proposed a mechanism for chopping transaction while still preserving the traditional criterion for correctness. This approach uses limited semantic information of transactions and its main motivation is to improve performance by splitting transactions into smaller units. Kaiser has ....

D. Shasha, E. Simon, and P. Valduriez. Simple Rational Guidance for Chopping Up Transactions. In Proceedings of the 1992 ACM SIGMOD International Conference on Management of Data, pages 298--307, June 1992.

....executions are guaranteed to be 1SR. 2. No validation needs to be done during runtime. The second goal above implies that no read only subtransaction will violate serializability as a result of transformation. To fulfill these goals, we resort to a special graph introduced by Shasha et al. In [SSV92] Shasha et al. propose a technique to statically partition transactions into pieces. Each piece is scheduled by 2PL. A chopping graph is used to guarantee that the resulting executions are serializable if the chopping graph satisfies a special property. Shasha s chopping graph is an undirected ....

Dennis Shasha, Eric Simon, and Patrick Valduriez. Simple rational guidance for chopping up transactions. In Proc. ACM SIGMOD Intl Conf, pages 298--307, June 1992.

.... program data independence) Also, many query optimizers have well known weaknesses, so that rephrasing of queries may be justified (see, e.g. 15] Finally, performance problems due to data contention are often resolved by chopping up a long unit of work into a chain of subsequent transactions [77]. For interactive programs, this may even require some special end user training, since data consistency may not be guaranteed hundred percent [32] 4. Adjustment of Operational Parameters: This stage takes place upon the startup of the database system. The system is configured with a set of ....

D. Shasha, E. Simon and P. Valduriez. Simple Rational Guidance for Chopping Up Transactions. ACM SIGMOD International Conference on Management of Data, San Diego (1992).

....into a read only subtransaction followed by an updating subtransaction, i.e. by delaying the write operations of an updater to a second piece. The read only subtransaction can be scheduled with no blocking like ordinary read only transactions. The chopping graph proposed by Shasha et al. in [SSV92] provides a suitable method for transforming update transactions while still guaranteeing serializability, avoiding the validation phase required by delayed write schemes in optimistic concurrency control. Each transformed updater is represented by two nodes in the chopping graph, connected by an ....

Dennis Shasha, Eric Simon, and Patrick Valduriez. Simple rational guidance for chopping up transactions. In Proc. ACM SIGMOD Intl Conf, pages 298--307, June 1992.

....specification when new transaction types are added. Currently, there is no methodology for maintaining such a specification incrementally (i.e. without repeating the complete analysis of allowable interleavings) Both problems are addressed, to some extent, by the transaction chopping approach of [SSV92], which aims to derive the interleaving specification automatically from the data access patterns of the transaction types (e.g. at the SQL level) This approach would still ensure serializability of the original transactions, but would chop up transactions into multiple independent ....

Shasha, D., Simon, E., Valduriez, P., Simple Rational Guidance for Chopping Up Transactions, ACM SIGMOD Conference, 1992

....Dept. of Computer Sciences Chang Jung University Purdue University May 1995 Key words: Concurrency, databases, real time systems. 1 Introduction Shasha et al. recently described a chopping graph analysis for dividing transactions into smaller pieces, and thus reducing potential blocking [6]. Shasha et al. prove the correctness of this transformation provided transactions are scheduled by two phase locking. 1 We generalize Shasha s result by showing that chopping is safe for all single version serializable schedulers, and not just two phase locking. Further, we show that chopping ....

....that the goal of database concurrency control is to maintain an illusion of exclusive access of transactions while permitting concurrent access at the level of individual operations. This notion is formally captured by serializability theory [4] 1 Although the statement of the abstract of [6] appears somewhat more general, the proof is based on a 2 phase locking protocol. 1 2 SINGLE VERSION SCHEDULES 2 Many concurrency control protocols have been devised to enforce serializability, and serializability theory has been extended from single version to multi version schedules, e.g. ....

[Article contains additional citation context not shown here]

Dennis Shasha, Eric Simon, and Patrick Valduriez. Simple rational guidance for chopping up transactions. In Proc. ACM SIGMOD Intl Conf, pages 298--307, June 1992.

No context found.

D. Shasha, E. Simon, and P. Valduriez. Simple rational guidance for chopping up transactions. Proceedings ACM SIGMOD, pages 298--307, May 1992.

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