Top 3 Java Xquery Projects

sirix

44 1,079 9.2 Java

SirixDB is an an embeddable, bitemporal, append-only database system and event store, storing immutable lightweight snapshots. It keeps the full history of each resource. Every commit stores a space-efficient snapshot through structural sharing. It is log-structured and never overwrites data. SirixDB uses a novel page-level versioning approach.

Project mention: Show HN: Integer Map Data Structure | news.ycombinator.com | 2024-01-24

We're using a similar trie structure as the main document (node) index in SirixDB[1]. Lately, I got some inspiration for different page-sizes based on the ART and HAMT basically for the rightmost inner pages (as the node-IDs are generated by a simple sequence generator and thus also all inner pages (we call them IndirectPage) except for the rightmost are fully occupied (the tree height is adapted dynamically depending on the size of the stored data. Currently, always 1024 references are stored to indirect child pages, but I'll experiment with smaller sized, as the inner nodes are simply copied for each new revision, whereas the leaf pages storing the actual data are versioned themselfes with a novel sliding snapshot algorithm.
You can simply compute from a unique nodeId each data is assigned (64bit) the page and reference to traverse on each level in the trie through some bit shifting.
[1] https://github.com/sirixdb/sirix

eXist

0 408 9.7 Java

eXist Native XML Database and Application Platform
InfluxDB

www.influxdata.com sponsored

Power Real-Time Data Analytics at Scale. Get real-time insights from all types of time series data with InfluxDB. Ingest, query, and analyze billions of data points in real-time with unbounded cardinality.
brackit

21 46 6.9 Java

Query processor with proven optimizations, ready to use for your JSON store to query semi-structured data with JSONiq. Can also be used as an ad-hoc in-memory query processor.

Project mention: Show HN: Bitemporal, Binary JSON Based DBS and Event Store | news.ycombinator.com | 2023-11-13

NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020).