datafusion-postgres

A PostgreSQL-compatible server frontend for Apache DataFusion. Available as both a library and CLI tool.

Built on pgwire to provide PostgreSQL wire protocol compatibility for analytical workloads. It was originally an example of the pgwire project.

Scope of the Project

• datafusion-postgres: Postgres frontend for datafusion, as a library.
  • Serving Datafusion SessionContext with pgwire library
  • Customizible/Optional authentication and Permission control
• datafusion-pg-catalog: A Postgres compatible pg_catalog schema and functions for datafusion backend.
• arrow-pg: A data type mapping, encoding/decoding library for arrow and postgres(pgwire) data types.
• datafusion-postgres-cli: A cli tool starts a postgres compatible server for datafusion supported file formats, just like python's SimpleHTTPServer.

Supported Database Clients

• Database Clients
  • psql
  • DBeaver
  • pgcli
  • VSCode SQLTools
  • Intellij Datagrip
• BI
  • Metabase
  • PowerBI

Quick Start

The Library datafusion-postgres

The high-level entrypoint of datafusion-postgres library is the serve function which takes a datafusion SessionContext and some server configuration options.

use std::sync::Arc;
use datafusion::prelude::SessionContext;
use datafusion_postgres::{serve, ServerOptions};
use datafusion_pg_catalog::setup_pg_catalog;

// Create datafusion SessionContext
let session_context = Arc::new(SessionContext::new());
// Configure your `session_context`
// ...

// Optional: setup pg_catalog schema
setup_pg_catalog(session_context, "datafusion")?;

// Start the Postgres compatible server with SSL/TLS
let server_options = ServerOptions::new()
    .with_host("127.0.0.1".to_string())
    .with_port(5432)
    // Optional: setup tls
    .with_tls_cert_path(Some("server.crt".to_string()))
    .with_tls_key_path(Some("server.key".to_string()));

serve(session_context, &server_options).await

Security Features

The server automatically includes:

• User authentication (default postgres superuser)
• Role-based access control with predefined roles:
  • readonly: SELECT permissions
  • readwrite: SELECT, INSERT, UPDATE, DELETE permissions
  • dbadmin: Full administrative permissions
• SSL/TLS encryption when certificates are provided
• Query-level permission checking

The CLI datafusion-postgres-cli

Command-line tool to serve JSON/CSV/Arrow/Parquet/Avro files as PostgreSQL-compatible tables.

datafusion-postgres-cli 0.6.1
A PostgreSQL interface for DataFusion. Serve CSV/JSON/Arrow/Parquet files as tables.

USAGE:
    datafusion-postgres-cli [OPTIONS]

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information

OPTIONS:
        --arrow <arrow-tables>...        Arrow files to register as table, using syntax `table_name:file_path`
        --avro <avro-tables>...          Avro files to register as table, using syntax `table_name:file_path`
        --csv <csv-tables>...            CSV files to register as table, using syntax `table_name:file_path`
    -d, --dir <directory>                Directory to serve, all supported files will be registered as tables
        --host <host>                    Host address the server listens to [default: 127.0.0.1]
        --json <json-tables>...          JSON files to register as table, using syntax `table_name:file_path`
        --parquet <parquet-tables>...    Parquet files to register as table, using syntax `table_name:file_path`
    -p <port>                            Port the server listens to [default: 5432]
        --tls-cert <tls-cert>            Path to TLS certificate file for SSL/TLS encryption
        --tls-key <tls-key>              Path to TLS private key file for SSL/TLS encryption

🔒 Security Options

# Run with SSL/TLS encryption
datafusion-postgres-cli \
  --csv data:sample.csv \
  --tls-cert server.crt \
  --tls-key server.key

# Run without encryption (development only)
datafusion-postgres-cli --csv data:sample.csv

📋 Example Usage

Basic Example

Host a CSV dataset as a PostgreSQL-compatible table:

datafusion-postgres-cli --csv climate:delhiclimate.csv

Loaded delhiclimate.csv as table climate
TLS not configured. Running without encryption.
Listening on 127.0.0.1:5432 (unencrypted)

Connect with psql

🔐 Authentication: The default setup allows connections without authentication for development. For secure deployments, use DfAuthSource with standard pgwire authentication handlers (cleartext, MD5, or SCRAM). See auth.rs for implementation examples.

psql -h 127.0.0.1 -p 5432 -U postgres

postgres=> SELECT COUNT(*) FROM climate;
 count
-------
  1462
(1 row)

postgres=> SELECT date, meantemp FROM climate WHERE meantemp > 35 LIMIT 5;
    date    | meantemp
------------+----------
 2017-05-15 |     36.9
 2017-05-16 |     37.9
 2017-05-17 |     38.6
 2017-05-18 |     37.4
 2017-05-19 |     35.4
(5 rows)

postgres=> BEGIN;
BEGIN
postgres=> SELECT AVG(meantemp) FROM climate;
       avg
------------------
 25.4955206557617
(1 row)
postgres=> COMMIT;
COMMIT

🔐 Production Setup with SSL/TLS

# Generate SSL certificates
openssl req -x509 -newkey rsa:4096 -keyout server.key -out server.crt \
  -days 365 -nodes -subj "/C=US/ST=CA/L=SF/O=MyOrg/CN=localhost"

# Start secure server
datafusion-postgres-cli \
  --csv climate:delhiclimate.csv \
  --tls-cert server.crt \
  --tls-key server.key

Loaded delhiclimate.csv as table climate
TLS enabled using cert: server.crt and key: server.key
Listening on 127.0.0.1:5432 with TLS encryption

Community

Developer Mailing List

If you like the idea of pgwire, datafusion-postgres and want to join the development of the library, or its ecosystem integrations, extensions, you are welcomed to join our developer mailing list: https://groups.io/g/pgwire-dev/

License

This library is released under Apache license.