How to Install QLever

How do I get QLever?

Prerequisites

Before installing QLever, ensure that your system meets the following requirements:

Operating System: Ubuntu (18.04 or later recommended), macOS, or Windows Subsystem for Linux (WSL).
Python: Version 2.7 or higher.
Hardware:
- Minimum: 4 GB RAM, 4 CPU cores
- Optional: Docker (for containerized deployment)

Note: QLever generally requires CMake 3.10 or higher.

Installation Methods

Option 1: Using Python and Pip (Recommended for local installations)

Install QLever

Run the following command in your terminal to install QLever using pip:

pip install qlever

Verify the Installation:

Check that QLever was installed successfully:

qlever --version

(This runs QLever on port 7001.)

Option 2: Using Docker (Recommended for Production or Large-Scale Setups)

Pull the QLever Docker Image:

docker pull qlever/qlever

Run QLever in a Container:

docker run -d -p 7001:7001 qlever/qlever

Configuration Setup

Once installed, you need to configure QLever to work with your dataset. QLever uses configuration files (Qleverfile) to define dataset locations and settings.

Create a Qleverfile

Use the command below to create a configuration file for a sample dataset (e.g., Wikidata):

qlever setup-config wikidata

Edit the Configuration:

Open the configuration file and modify it to point to your dataset location and adjust the memory limits as needed:

nano qlever_config.json

Running QLever

To start the QLever engine after configuration:

Index the dataset

Indexing is required for QLever to query the dataset efficiently.

qlever index --config qlever_config.json

Start the QLever Server:

qlever start --config qlever_config.json

Verifying the Installation:

To verify that QLever is running correctly:

Open your browser and navigate to:

http://localhost:7001

Execute a test query (e.g., SELECT * WHERE {?s ?p ?o} LIMIT 10) to verify that the server responds.