User: lichtenberger

  • Created: 1622 days ago
  • Karma: 1280
  • I'm working on an evolutionary, accumulate-only database system called SirixDB written in Java (and a module in Kotlin) in my spare time and in my day to day job I'm also working as a software engineer (besides I'm dancing a lot -- swing dances, mainly Lindy Hop and travel to festivals in Europe often times in my holidays) :-)

    Furthermore, I'm working on Brackit (, a query engine for JSON and XML using a JSONiq like query language. It can be used as ad-hoc in-memory query processor as the query processor of a data store. We envision, that it encapsulates common proven optimizations whereas the individual data stores can add further stages to rewrite the queries for index matching and physical optimizations.

    SirixDB ( or is all about efficient versioning of your data. That is on the one hand it reduces the storage cost of storing a new revision during each transaction-commit while balancing read- and write-performance through a novel sliding snapshot algorithm and dynamic page compression. On the other hand Sirix supports easy query capabilities for instance to open a specific revision by a timestamp or several revisions by a given timespan, to navigate to future or past versions of nodes in the tree-structure and so on. It basically never overwrites data and is heavily inspired by ZFS and Git and borrows some ideas and puts these to test on the sub-file level.

    In stark contrast to other approaches SirixDB combines copy-on-write semantics with node-level versioning and does not require a write-ahead-log for consistency.

    It all started around 2006 as a university / Ph.D. project of Marc Kramis and I worked on the project since 2007 and already did my Bachelor's Thesis, Master's Thesis as well as several HiWi-Jobs on topics regarding the project and I'm still more eager than ever to put forth the idea of a versioned, analytics plattform to perform analytical tasks based on current as well as the history of the data.

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