Mutual exclusion (mutex) locks limit concurrency but offer low single-thread latency. Software transactional memory (STM) typically has much higher latency, but scales well. We present transactional mutex locks (TML), which attempt to achieve the best of both worlds for read-dominated workloads. We also propose compiler optimizations that reduce the latency of TML to within a small fraction of ...

An approach to modelling an Oracle database is presented for both single instance and parallel server versions. A modified queueing network is used which is extended to include traditional transaction locks which achieve serialisation and the new PCM locks of Oracle which ensure coherency in the distributed database buffers. The latter are not enqueue locks and so require different techniques. ...

This paper proposes a locking protocol which associates locks with sets of resources. This protocol allows simultaneous locking at various granularities by different transactions. It is based on the introduction of additional lock modes besides the conventional share mode and exclusive mode. The protocol is generalized from simple hierarchies of locks to directed acyclic graphs of locks and to ...

Electronic door locks have recently become popular since they have many benefits compared with traditional mechanical locks. For example, in the case of keyless locks which are the most popular types of electronic door locks, a physical key is not needed anymore. They might also be invulnerable to the existing physical attacks against mechanical door locks[1]. Despite these known benefits of el...

Objectives—One way law enforcement oYcers support firearm safety is by promoting the use of gun locks. This investigation examined law enforcement oYcers’ willingness to use gun locks on their own guns, as well as their opinions regarding gun locks in general. Setting—Law enforcement oYcers from an urban agency in the southern region of the United States. Methods—Free keyed cable gun locks were...

ešects and checking are implemented in the compiler. emore speculative gradual ešect checking remains to be implemented. We have also not yet completely formalized or proven the soundness of the gradual ešect system. 5.5 Unlocking Ešects Using ešects for data race-free parallelism is conceptually very similar to using locks. Annotating a method with an ešect clause ešectively locks the data des...

Multicore machines are quickly shifting to NUMA and CC-NUMA architectures, making scalable NUMA-aware locking algorithms, ones that take into account the machines’ non-uniform memory and caching hierarchy, ever more important. This paper presents lock cohorting, a general new technique for designing NUMA-aware locks that is as simple as it is powerful. Lock cohorting allows one to transform any...

In this paper, we present an empirical analysis of the object-oriented database concurrency control mechanism named OC as specified in Olsen (1995). OC is a lock-based mechanism that is designed specifically to take advantage of the object-oriented database model as specified in Kim (1990). The OC strategy is two-phased and uses eight different kinds of locks. The eight types of locks are Inten...

Activation of a number of class A G protein-coupled receptors (GPCRs) is thought to involve two molecular switches, a rotamer toggle switch within the transmembrane domain and an ionic lock at the cytoplasmic surface of the receptor; however, the mechanism by which agonist binding changes these molecular interactions is not understood. Importantly, 80% of GPCRs including free fatty acid recepto...

When many concurrent transactions like ERP and E-commerce orders want to update the same stock records, long duration locking may reduce the availability of the locked data. Therefore, transactions are often designed without analyzing the consequences of loosing the traditional ACID (Atomicity, Consistency, Isolation and Durability) properties. In this paper, we will analyze how low isolation l...