Multi-Version Concurrency Control (MVCC) is a widely employed concurrency control mechanism, as it allows for execution modes where readers never block writers. However, most systems implement only Snapshot Isolation (SI) instead of full serializability. Adding serializability guarantees to existing SI implementations tends to be prohibitively expensive. The authors present a novel MVCC implementation for main-memory ...

Existing database systems employ an eager transaction processing scheme – that is, upon receiving a transaction request, the system executes all the operations entailed in running the transaction before reporting to the client that the transaction has completed. The authors introduce a lazy transaction execution engine, in which a transaction may be considered durably completed ...

The linked data initiative brought new opportunities for building the next generation of Web applications. However, the full potential of linked data depends on how easy it is to transform data stored in relational databases into RDF (Resource Description Framework) triples. Recently, the W3C RDB2RDF working group proposed a mapping language, called R2RML, to specify ...

Open-source local file systems, such as Linux Ext4, XFS, and Btrfs, remain a critical component in the world of modern storage. For example, many recent distributed file systems, such as Google GFS and Hadoop DFS, replicate data objects (and associated metadata) across local file systems. The authors conduct a comprehensive study of file-system code evolution. ...

Commercial analytical database systems suffer from a high “Time-to-first-analysis”: before data can be processed, it must be modeled and schematized, transferred into the database’s storage layer, and optionally clustered and indexed. For many types of structured data, this upfront effort is unjustifiable, so the data are processed directly over the file system using the Hadoop ...

In spite of the omnipresence of parallel (multi-core) systems, the predominant strategy to evaluate window-based stream joins is still strictly sequential, mostly just straightforward along the definition of the operation semantics. In this paper, the author’s present handshake join, a way of describing and executing window-based stream joins that is highly amenable to parallelized execution. ...

Modern computer systems have been built around the assumption that persistent storage is accessed via a slow, block-based interface. However, new byte-addressable, persistent memory technologies such as Phase Change Memory (PCM) offer fast, fine-grained access to persistent storage. In this paper, the authors present a file system and a hardware architecture that are designed around ...

There has been a significant amount of excitement and recent work on column-oriented database systems (“Column-stores”). These database systems have been shown to perform more than an order of magnitude better than traditional row-oriented database systems (“Row-stores”) on analytical workloads such as those found in data warehouses, decision support, and business intelligence applications. The elevator ...

There has been a great deal of hype about Amazon’s Simple Storage Service (S3). S3 provides infinite scalability and high availability at low cost. Currently, S3 is used mostly to store multi-media documents (videos, photos, audio) which are shared by a community of people and rarely updated. The purpose of this paper is to demonstrate ...