Alpha — not production-ready. APIs will change without notice.

Pure-Java reader/writer for the Vortex columnar file format. 100% Java, no JNI, no sun.misc.Unsafe. Uses the FFM API (MemorySegment/Arena, Java 25+) for zero-copy memory-mapped reads.

• JVM analytics engines and OLAP systems
• Anyone who wants mmap-backed, zero-copy columnar reads without native-library management

<dependency>
  <groupId>io.github.dfa1.vortex</groupId>
  <artifactId>reader</artifactId>
  <version>0.2.0</version>
</dependency>

try (VortexReader vf = VortexReader.open(Path.of("data/example.vortex"));
     var iter = vf.scan(ScanOptions.all())) {
    while (iter.hasNext()) {
        var chunk = iter.next();
        LongArray ts = chunk.column("timestamp");
        for (long i = 0; i < ts.length(); i++) {
            System.out.println(ts.getLong(i));
        }
    }
}

Note: iter.hasNext() closes the previous chunk's arena. Access all column data before calling hasNext() again. See docs/explanation.md#memory-model.

For more examples — writing, projection, filtering, custom encodings, and the CLI — see the documentation below.

Docs follow the Diátaxis framework.

Requirements: Java 25+

Generated sources (fbs/proto → Java) are committed. Normal builds need no external tools.

./mvnw verify          # build + tests
./mvnw verify -DskipTests

# run integration tests
./mvnw verify -pl integration -am

# benchmarks (always pass ClassName.methodName filter)
./bench RustVsJavaReadBenchmark.javaReadVolume

To regenerate schemas after editing .fbs/.proto:

brew install flatbuffers protobuf
./mvnw generate-sources -pl core -P regenerate-sources

Forks and contributions welcome. Include tests and update documentation where applicable (see CLAUDE.md for guidelines).

This project uses Claude Code for implementation work. Architecture, API design, and all decisions are human-driven.