PeerDB is fundamentally made up of two parts: the platform and the connectors.

The platform encompasses the essential services necessary to configure and run data querying and movement operations, which include the Nexus Query Layer and the Flow Data Transfer Component.

  • Nexus Query Layer: Located in the nexus subfolder in the root repository, Nexus is a Rust-implemented service that enables Postgres-compatible SQL querying across various data sources and sinks. It supports the PGWire protocol and can be horizontally scaled to manage high demand.

  • Flow Data Transfer Component: Stored in the flow subfolder of the root repository, Flow is written in Golang. It manages data transfer between sources and sinks, and consists of a Flow API and horizontally scalable Flow Workers.

The connectors signify various data sources and sinks that PeerDB can interact with. They include databases like Postgres, MySQL (sources), and Bigquery, Snowflake (sinks).

Detailed Components

  • Nexus Query Layer: This is the user interface to run SQL queries. It communicates with both data sources and sinks.

  • Flow Data Transfer Component: It has two parts - the Flow API that manages the process and the Flow Workers that perform the actual data transfer.

  • Sources: These are the databases from which data can be fetched, like Postgres and MySQL.

  • Sinks: These are the databases where data can be deposited, like Bigquery and Snowflake.


PeerDB has two primary dependencies:

  1. Temporal Orchestration Engine: This external service orchestrates the data transfer process within the Flow component.

  2. Catalog Database (Postgres): This database stores metadata related to PeerDB’s operations.

The main strengths of PeerDB are its scalability and flexibility, allowing for the addition of Nexus and Flow Worker instances to handle increased load efficiently.