Stefanie Scherzinger

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We introduce an extension of the XQuery language, FluX, that supports event-based query processing and the conscious handling of main memory buffers. Purely event-based queries of this language can be executed on streaming XML data in a very direct way. We then develop an algorithm that allows to efficiently rewrite XQueries into the event-based FluX(More)
We introduce the notion of XML Stream Attribute Grammars (XSAGs). XSAGs are the first scalable query language for XML streams (running strictly in linear time with bounded memory consumption independent of the size of the stream) that allows for actual data transformations rather than just document filtering. XSAGs are also relatively easy to use for(More)
Effective buffer management is crucial for efficient in-memory and streaming XQuery processing. We propose a buffer management scheme which combines static and dynamic analysis to keep main memory consumption low. Our approach relies on a technique that we call active garbage collection and which actively purges buffers at runtime based on the current(More)
XML has established itself as the ubiquitous format for data exchange on the Internet. An imminent development is that of streams of XML data being exchanged and queried. Data management scenarios where XQuery [11] is evaluated on XML streams are becoming increasingly important and realistic, e.g. in e-commerce settings. Naturally, query engines employed(More)
NoSQL data stores are becoming increasingly popular in application development. These systems are attractive for developers due to their ability to handle large volumes of data, as well as data with a high degree of structural variety. Typically, NoSQL data stores are accessed programmatically. Due to the imminent lack of standardized query languages,(More)
We propose a new technique for the efficient search and navigation in XML documents and streams. This technique takes string matching algorithms designed for efficient keyword search in flat strings into the second dimension, to navigate in tree structured data. We consider the important XML data management task of prefiltering XML documents (also called(More)
In this demonstration, we present the main-memory based streaming XQuery engine GCX which implements novel buffer management strategies that combine static and dynamic analysis to keep main memory consumption low. Depending on the progress made in query evaluation, memory buffers are dynamically purged and minimized. In this demo, we show the various stages(More)
Although most NoSQL Data Stores are schema-less, information on the structural properties of the persisted data is nevertheless essential during application development. Otherwise, accessing the data becomes simply impractical. In this paper, we introduce an algorithm for schema extraction that is operating outside of the NoSQL data store. Our method is(More)