Graphflow is an in-memory graph database that supports continuous queries. Graphflow's query language is based on openCypher. Currently Graphflow supports a subset of queries expressible in openCypher. In addition it supports several extensions to openCypher for expressing continuous queries. Throughout the code base and documentation, we refer to this extended version of openCypher as openCypher++.

A key feature of Graphflow is the use of the worst-case optimal Generic Join algorithm to do one-time and continuous match queries.

Graphflow requires Java 8, and uses Gradle as its build tool.

• Do a full clean build: ./gradlew clean build installDist
• Subsequent builds: ./gradlew build installDist
• Build without tests: ./gradlew build installDist -x test

Gradle creates helper scripts for running the server and the client. Once the build is successful, run the scripts in two different terminals.

• Start Graphflow server:
  ./build/install/graphflow/bin/graphflow-server
• Start Graphflow CLI:
  ./build/install/graphflow/bin/graphflow-cli

The CLI can now be used to interact with the server using openCypher++ queries.

The Graphflow server logs to stdout by default. To change the logging mechanism, provide a custom log4j2 config file:

export GRAPHFLOW_SERVER_OPTS="-Dlog4j.configurationFile=file:/path/to/log4j2.properties"  
./build/install/graphflow/bin/graphflow-server

Graphflow is an open source software under the Apache 2.0 license.