Steffen Friedrich

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There are numerous approaches towards quantifying the performance of NoSQL datastores with respect to dimensions that are notoriously hard to capture such as staleness or consistency in general. Many of these approaches, though, are built on assumptions regarding the underlying infrastructure or the test scenario and may lead to invalid results, if those(More)
1 " InformatischeBildung " –oderwas man darunterversteht DieBildungsmisere in Deutschland istinzwischenein Themageworden, mitdem es sich ganz gut in derÖ ffentlichkeit punkten lässt.E ss cheint fast akzeptiert, dass deutsche Schülerinnenu nd Schüler in internationalenVergleichenn ur im Mittelfeldl anden, dass dieWirtschaftinsbesondere im Bereichder(More)
The expiration-based caching model of the web is generally considered irreconcilable with the dynamic workloads of cloud database services, where expiration dates are not known in advance. In this paper, we present the Cache Sketch data structure which makes expiration-based caching of database records feasible with rich tun-able consistency guarantees. The(More)
In the last years, many database-as-a-service (DBaaS) systems have started to offer their functionalities through REST APIs. Examples are record stores like DynamoDB and Azure Tables, object stores such as Amazon S3 as well as many NoSQL database systems, for instance Riak, CouchDB and ElasticSearch. Yet today, there has been no systematic effort on(More)