Publications related to Snapshot isolation

Oligolithic Cross-task Optimizations across Isolated Workloads

Anastasia Ailamaki, Eleni Zapridou, Panagiotis Sioulas

Enterprises collect data in large volumes and leverage them to drive numerous concurrent decisions and business processes. Their teams deploy multiple applications that often operate concurrently on the same data and infrastructure but have widely differen ...

2024

When is it safe to run a transactional workload under Read Committed?

Christoph Koch, Bas Ketsman

The popular isolation level multiversion Read Committed (RC) exchanges some of the strong guarantees of serializability for increased transaction throughput. Nevertheless, transaction workloads can sometimes be executed under RC while still guaranteeing se ...

ASSOC COMPUTING MACHINERY2023

Organocatalytic Enantioselective Pictet–Spengler Reaction of α‐Ketoesters: Development and Application to the Total Synthesis of (+)‐Alstratine A

Qian Wang, Jieping Zhu, Rémi Julien Sylvain Andres, Fenggang Sun

We report herein an asymmetric Pictet– Spengler reaction of α-ketoesters. In the presence of a catalytic amount of simple alanine-derived squaramide and p-nitrobenzoic acid, reaction of tryptamines with methyl 2-oxoalkanoates afforded the corresponding 1- ...

Wiley-VCH Verlag GmbH2023

Concurrency control for database theorists

Christoph Koch, Bas Ketsman

The aim of this paper is to serve as a lightweight introduction to concurrency control for database theorists through a uniform presentation of the work on robustness against Multiversion Read Committed and Snapshot Isolation. ...

ASSOC COMPUTING MACHINERY2022

Deciding Robustness for Lower SQL Isolation Levels

Christoph Koch, Bas Ketsman

While serializability always guarantees application correctness, lower isolation levels can be chosen to improve transaction throughput at the risk of introducing certain anomalies. A set of transactions is robust against a given isolation level if every p ...

ASSOC COMPUTING MACHINERY2022

Robustness against Read Committed for Transaction Templates

Christoph Koch, Bas Ketsman

The isolation level Multiversion Read Committed (RC), offered by many database systems, is known to trade consistency for increased transaction throughput. Sometimes, transaction workloads can be safely executed under RC obtaining the perfect isolation of ...

ASSOC COMPUTING MACHINERY2021

Efficient Protocols for Enforcing Causal Consistency in Geo-Replicated Key-Value Data Stores

Kristina Spirovska

Modern large-scale data platforms manage colossal amount of data, generated by the ever-increasing number of concurrent users. Geo-replicated and sharded key-value data stores play a central role when building such platforms. As the strongest consistency m ...

EPFL2020

Deciding Robustness for Lower SQL Isolation Levels

Christoph Koch, Bas Ketsman

While serializability always guarantees application correctness, lower isolation levels can be chosen to improve transaction throughput at the risk of introducing certain anomalies. A set of transactions is robust against a given isolation level if every p ...

ASSOC COMPUTING MACHINERY2020

Resolving bundle-specific intra-axonal T2 values within a voxel using diffusion-relaxation tract-based estimation

Jean-Philippe Thiran, Erick Jorge Canales Rodriguez, Alessandro Daducci, Muhamed Barakovic, Cristina Granziera

At the typical spatial resolution of MRI in the human brain, approximately 60–90% of voxels contain multiple fiber populations. Quantifying microstructural properties of distinct fiber populations within a voxel is therefore challenging but necessary. Whil ...

2020

The PCL Theorem: Transactions cannot be Parallel, Consistent, and Live

Rachid Guerraoui, Victor Bushkov, Panagiota Fatourou

We establish a theorem called the PCL theorem, which states that it is impossible to design a transactional memory algorithm that ensures (1) parallelism, i.e., transactions do not need to synchronize unless they access the same application objects, (2) ve ...

ASSOC COMPUTING MACHINERY2019

PaRiS: Causally Consistent Transactions with Non-blocking Reads and Partial Replication

Willy Zwaenepoel, Diego Didona, Kristina Spirovska

Geo-replicated data platforms are at the backbone of several large-scale online services. Transactional Causal Consistency (TCC) is an attractive consistency level for building such platforms. TCC avoids many anomalies of eventual consistency, eschews the ...

2019

PaRiS: Causally Consistent Transactions with Non-blocking Reads and Partial Replication

Willy Zwaenepoel, Diego Didona, Kristina Spirovska

Geo-replicated data platforms are the backbone of several large-scale online services. Transactional Causal Consistency (TCC) is an attractive consistency level for building such platforms. TCC avoids many anomalies of eventual consistency, eschews the syn ...

IEEE COMPUTER SOC2019

Plug-and-Play Fault Detection and Isolation for Large-Scale Nonlinear Systems With Stochastic Uncertainties

Giancarlo Ferrari Trecate

This paper proposes a novel scalable model-based fault detection and isolation approach for the monitoring of nonlinear large-scale systems, consisting of a network of interconnected subsystems. The fault diagnosis architecture is designed to automatically ...

2019

Fast General Distributed Transactions with Opacity

Aleksandar Dragojevic, Georgios Chatzopoulos, Stanko Novakovic

Transactions can simplify distributed applications by hiding data distribution, concurrency, and failures from the application developer. Ideally the developer would see the abstraction of a single large machine that runs transactions sequentially and neve ...

ASSOC COMPUTING MACHINERY2019

Locking Timestamps versus Locking Objects

Rachid Guerraoui, Tudor Alexandru David, Junxiong Wang

We present multiversion timestamp locking (MVTL), a new genre of multiversion concurrency control algorithms for serializable transactions. The key idea behind MVTL is simple: lock individual timestamps instead of locking objects. After presenting a generi ...

ASSOC COMPUTING MACHINERY2018

Universally Scalable Concurrent Data Structures

Tudor Alexandru David

The increase in the number of cores in processors has been an important trend over the past decade. In order to be able to efficiently use such architectures, modern software must be scalable: performance should increase proportionally to the number of all ...

EPFL2017

Optimistic Concurrency with OPTIK

Rachid Guerraoui, Vasileios Trigonakis

We introduce OPTIK, a new practical design pattern for designing and implementing fast and scalable concurrent data structures. OPTIK relies on the commonly-used technique of version numbers for detecting conflicting concurrent operations. We show how to i ...

ACM Press2016

The PCL Theorem. Transactions cannot be Parallel, Consistent and Live

Rachid Guerraoui, Victor Bushkov, Panagiota Fatourou

We show that it is impossible to design a transactional memory system which ensures parallelism, i.e. transactions do not need to synchronize unless they access the same application objects, while ensuring very little consistency, i.e. a consistency condit ...

2014

Consistency Models in Distributed Systems with Physical Clocks

Jiaqing Du

Most existing distributed systems use logical clocks to order events in the implementation of various consistency models. Although logical clocks are straightforward to implement and maintain, they may affect the scalability, availability, and latency of t ...

EPFL2014

Clock-SI: Snapshot Isolation for Partitioned Data Stores Using Loosely Synchronized Clocks

Willy Zwaenepoel, Sameh Mohamed Elnikety, Jiaqing Du

Clock-SI is a fully distributed protocol that implements snapshot isolation (SI) for partitioned data stores. It derives snapshot and commit timestamps from loosely synchronized clocks, rather than from a centralized timestamp authority as used in current ...

2013