Semantic locking in object-oriented database systems

Resende, Rodolfo F.; Agrawal, Divyakant; Abbadi, Amr El

doi:10.1145/191080.191144

Cited by 23 publications

(23 citation statements)

References 12 publications

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“…Thus, methods on different objects may not commute [16]. The RSO (also called non-disjoint complex object) is a fundamental concern of OODB since new objects may be composed of existing objects in modular design as indicated in [17]. Thus, a nested object hierarchy may result in referential sharing.…”

Section: Nested Methods Invocationmentioning

confidence: 99%

“…For nested method invocations, either concurrency is still limited since semantic information is not utilized or too much run-time overhead is incurred since locks are required for each atomic operation. Also, most existing studies do not consider referentially shared objects (non-disjoint complex objects) which is a necessary condition for modular design in an OODB [17].…”

Section: Nested Methods Invocationmentioning

confidence: 99%

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Development of a Concurrency Control Technique for Multiple Inheritance in Object-Oriented Databases

Jun¹,

Hong²

2014

Journal of Korean Society for Internet Information

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Currently many non-traditional application areas such as artificial intelligence and web databases require advanced modeling power than the existing relational data model. In those application areas, object-oriented database (OODB) is better data model since an OODB can providemodeling power as grouping similar objects into class, and organizing all classes into a hierarchy where a subclass inherits all definitions from its superclasses.The purpose of this paper is to develop an OODB concurrency control scheme dealing with multiple inheritance. The proposed scheme, called Multiple Inheritance Implicit Locking (MIIL), is based on so-called implicit locking. In the proposed scheme, we eliminate redundant locks that are necessary in the existing implicit locking scheme. Intention locks are required as the existing implicit locking scheme. In this paper, it is shown that MIIL has less locking overhead than implicit locking does. We use only OODB inheritance hierarchies, single inheritance and multiple inheritance so that no additional overhead is necessary for reducing locking overhead.

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Section: Nested Methods Invocationmentioning

confidence: 99%

Section: Nested Methods Invocationmentioning

confidence: 99%

Development of a Concurrency Control Technique for Multiple Inheritance in Object-Oriented Databases

Jun¹,

Hong²

2014

Journal of Korean Society for Internet Information

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“…Semantic commutativity is frequently used in software conflict detection schemes [20,25,26,34,36,40,51]. Most work in this area focuses on techniques that reason about operations to abstract data types.…”

Section: A Semantic Commutativitymentioning

confidence: 99%

“…Most work in this area focuses on techniques that reason about operations to abstract data types. Not all commutativity-aware conflict detection schemes are equally precise: simple and general techniques, like semantic locking [25,40,51], flag some commutative operations as conflicts, while more sophisticated schemes, like gatekeepers [25], incur fewer conflicts but have higher overheads and are often specific to particular patterns.…”

Section: A Semantic Commutativitymentioning

confidence: 99%

“…In this work we focus on semantic locking [40,51], also known as abstract locking. Semantic locking generalizes readwrite locking schemes (e.g., two-phase locking): transactions can acquire a lock protecting a particular object in one of a number of modes; multiple semantically-commutative methods acquire the lock in a compatible mode and proceed concurrently.…”

Section: A Semantic Commutativitymentioning

confidence: 99%

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Exploiting semantic commutativity in hardware speculation

Zhang¹,

Chiu²,

Sánchez³

2016

2016 49th Annual IEEE/ACM International Symposium on Microarchitecture (MICRO)

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Abstract-Hardware speculative execution schemes such as hardware transactional memory (HTM) enjoy low run-time overheads but suffer from limited concurrency because they rely on reads and writes to detect conflicts. By contrast, software speculation schemes can exploit semantic knowledge of concurrent operations to reduce conflicts. In particular, they often exploit that many operations on shared data, like insertions into sets, are semantically commutative: they produce semantically equivalent results when reordered. However, software techniques often incur unacceptable run-time overheads.To solve this dichotomy, we present COMMTM, an HTM that exploits semantic commutativity. COMMTM extends the coherence protocol and conflict detection scheme to support user-defined commutative operations. Multiple cores can perform commutative operations to the same data concurrently and without conflicts. COMMTM preserves transactional guarantees and can be applied to arbitrary HTMs.COMMTM scales on many operations that serialize in conventional HTMs, like set insertions, reference counting, and top-K insertions, and retains the low overhead of HTMs. As a result, at 128 cores, COMMTM outperforms a conventional eager-lazy HTM by up to 3.4× and reduces or eliminates aborts.

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