xtdb: A Clojure repository from daveliepmann

XTDB is a general purpose database with graph-oriented bitemporal indexes. Datalog, SQL & EQL queries are supported, and Java, HTTP & Clojure APIs are provided.

XTDB follows an unbundled architectural approach, which means that it is assembled from decoupled components through the use of an immutable log and document store at the core of its design. A range of storage options are available for embedded usage and cloud native scaling.

Bitemporal indexing of schemaless documents enables broad possibilities for creating layered extensions on top, such as to add additional transaction, query, and schema capabilities. In addition to SQL, XTDB supplies a Datalog query interface that can be used to express complex joins and recursive graph traversals.

Quick Links

Documentation

Maven releases

<dependency>
  <groupId>com.xtdb</groupId>
  <artifactId>xtdb-core</artifactId>
  <version>1.23.1</version>
</dependency>

[com.xtdb/xtdb-core "1.23.1"]

com.xtdb/xtdb-core {:mvn/version "1.23.1"}

Release notes
Support: Zulip community chat | GitHub Discussions | hello@xtdb.com
Developing XTDB

Unbundled Architecture

XTDB embraces the transaction log as the central point of coordination when running as a distributed system. Use of a separate document store enables simple eviction of active and historical data to assist with technical compliance for information privacy regulations.

What do we have to gain from turning the database inside out? Simpler code, better scalability, better robustness, lower latency, and more flexibility for doing interesting things with data.

— Martin Kleppmann

This design makes it feasible and desirable to embed XTDB nodes directly within your application processes, which reduces deployment complexity and eliminates round-trip overheads when running complex application queries.

Repo Layout

XTDB is split across multiple projects which are maintained within this repository. core contains the main functional components of XTDB along with interfaces for the pluggable storage components (Kafka, LMDB, RocksDB etc.). Implementations of these storage options are located in their own projects.

Project directories are published to Maven independently so that you can maintain granular dependencies on precisely the individual components needed for your application.

Pre-Release Snapshot Builds

Maven snapshot versions are periodically published under dev-SNAPSHOT and are used to facilitate support and debugging activities during the development cycle. To access snapshots versions, the Sonatype snapshot repository must be added to your project definition:

<repository>
  <id>sonatype.snapshots</id>
  <name>Sonatype Snapshot Repository</name>
  <url>https://s01.oss.sonatype.org/content/repositories/snapshots</url>
  <releases>
    <enabled>false</enabled>
  </releases>
  <snapshots>
    <enabled>true</enabled>
  </snapshots>
</repository>

;; project.clj
:repositories [["sonatype snapshots" {:url "https://s01.oss.sonatype.org/content/repositories/snapshots"}]]

;; deps.edn
:mvn/repos {"sonatype snapshots" {:url "https://s01.oss.sonatype.org/content/repositories/snapshots"}}

In contrast to regular releases which are immutable, a dev-SNAPSHOT release can be "updated" - this mutability can often be useful but may also cause unexpected surprises when depending on dev-SNAPSHOT for longer than necessary. Snapshot versions, including full dev-<timestamp> coordinates (which are useful to avoid being caught out by mutation), can be browsed here.

Copyright & License

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Dependencies