Weak Consistency - A Generalized Theory and Optimistic Implementations for Distributed Transactions.pdf Current commercial databases allow application programmers to trade off consistency for performance. However, existing definitions of weak consistency levels are either imprecise or they disallow efficient implementation techniques such as optimism. Ruling out these techniques is especially unfortunate because commercial databases support optimistic mechanisms. Furthermore, optimism is ...

DB - aurora - Design Considerations for High Throughput Cloud-Native Relational Databases.pdf Amazon Aurora is a relational database service for OLTP workloads offered as part of Amazon Web Services (AWS). In this paper, we describe the architecture of Aurora and the design considerations leading to that architecture. We believe the central constraint in high throughput data processing has moved from compute and storage to the network. Aurora brings a novel architecture to the relational ...

We live in an increasingly interconnected world, with many organizations operating across countries or even continents. To serve their global user base, organizations are replacing their legacy DBMSs with cloud-based systems capable of scaling OLTP workloads to millions of users. CockroachDB is a scalable SQL DBMS that was built from the ground up to support these global OLTP workloads while maintaining high availability and strong consistency. Just like its namesake, CockroachDB is ...

The ongoing and increasing interest in HTAP (Hybrid Transactional and Analytical Processing) systems documents the intense interest from data owners in simultaneously running transactional and analytical workloads over the same data set. Much of the reported work on HTAP has arisen in the context of “greenfield” systems, answering the question “if we could design a system for HTAP from scratch, what would it look like?” While there is great merit in such an approach, and a lot of valuable ...

F1 Query is a stand-alone, federated query processing platform that executes SQL queries against data stored in different filebased formats as well as different storage systems at Google (e.g., Bigtable, Spanner, Google Spreadsheets, etc.). F1 Query eliminates the need to maintain the traditional distinction between different types of data processing workloads by simultaneously supporting: (i) OLTP-style point queries that affect only a few records; (ii) low-latency OLAP querying of large ...

This paper describes our experience implementing PostgreSQL’s new serializable isolation level. It is based on the recently-developed Serializable Snapshot Isolation (SSI) technique. This is the first implementation of SSI in a production database release as well as the first in a database that did not previously have a lock-based serializable isolation level. We reflect on our experience and describe how we overcame some of the resulting challenges, including the implementation of a new lock ...

DB - A Critique of ANSI SQL Isolation Levels.pdf ANSI SQL-92 [MS, ANSI] defines Isolation Levels in terms of phenomena: Dirty Reads, Non-Re-peatable Reads, and Phantoms. This document shows that these phenomena and the ANSI SQL definitions fail to characterize several popular isolation levels, including the standard locking implementations of the levels. Investigating the ambiguities of the phenomena leads to clearer definitions.

DB - Consistency Tradeoffs in Modern Distributed Database System Design The CAP theorem’s impact on modern distributed database system design is more limited than is often perceived. Another tradeoff—between consistency and latency —has had a more direct influence on several well-known DDBSs. A proposed new formulation, PACELC, unifies this tradeoff with CAP.

Database Engines on Multicores, Why Parallelize When You Can Distribute.pdf Multicore computers pose a substantial challenge to infrastructure software such as operating systems or databases. Such software typically evolves slower than the underlying hardware, and with multicore it faces structural limitations that can be solved only with radical architectural changes. In this paper we argue that, as has been suggested for operating systems, databases could treat multicore architectures

Title : Designing Distributed Systems Using Approximate Synchrony in Data Center Networks.pdf Distributed systems are traditionally designed independently from the underlying network, making worst-case assumptions (e.g., complete asynchrony) about its behavior. However, many of today’s distributed applications are deployed in data centers, where the network is more reliable, predictable, and extensible. In these environments, it is possible to co-design distributed systems with their network