PeerDB
PeerDB is an open-source change data capture engine built specifically for PostgreSQL sources, acquired by ClickHouse in 2024 and kept as a distinct component powering the managed Postgres CDC in ClickPipes.
LicenseOpen source (copyleft)· AGPL-3.0
DeploymentSelf-hostedManaged
PricingFreeSubscription
Operational complexityMedium
WorkloadStreamingBatch
LanguageGo
Use it when
- The pipe is Postgres to ClickHouse; PeerDB is the engine inside ClickPipes, and that path gets the most engineering attention.
- Postgres is the only source that matters and you want it done well: parallel CTID-partitioned snapshots, tuned slot handling, exactly-once delivery.
- Large initial loads hurt elsewhere; the parallel backfill is a headline feature.
- Self-hosting open source is acceptable, or the managed form inside ClickHouse Cloud is where you already are.
Think twice when
- Sources are diverse; Postgres and MySQL (MongoDB in preview) is the whole list, where Debezium spans seven engines and more.
- The destination roadmap matters; other warehouses and queues work, but the ClickHouse acquisition gives the roadmap an obvious center of gravity.
- Copyleft is a problem; the license is AGPL-3.0.
- Schema drift goes past added columns; drops and type changes do not propagate.
How it runs
Self-hosted as a Flow API with workers, a Postgres catalog, and Temporal for orchestration; sources need wal_level=logical, a publication and slot, and primary keys. Free to self-host; managed as ClickPipes, billed on compute hours plus data ingested.
Details
CompareHow PeerDB answers the questions Change Data Capture turns on.
Change Data Capture
| How it works | |
| Initial snapshot | Parallel initial load, partitioned by CTID |
| End-to-end lag | Near real-time; streams from the slot on a configurable sync interval |
| Delivery guarantee | Exactly-once |
| Schema drift | ADD COLUMN propagates; drops and type changes don't |
| Running it | |
| What you run | Flow API and workers, a Postgres catalog and Temporal |
| Connections | |
| Sources | PostgreSQL and MySQL; MongoDB in preview |
| Source requirements | wal_level logical, a publication and slot, and a primary key |
| Transformations | None in the pipeline; Lua row transforms when writing to queues |
| Destinations | ClickHouse first; other warehouses and queues |
| Cost | |
| Billing unit | Free self-hosted; ClickPipes bills compute hours plus GB ingested |
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