Warning: XMIN Got Frozen

Issue

The following warning appears in Fivetran:

XMIN got frozen

The message data is also extracted by the Fivetran Platform Connector.

Environment

Connector: PostgreSQL
Incremental sync method: Query-Based

Resolution

When this warning occurs, Fivetran automatically re-syncs the affected table.

To prevent this issue, change your connection's incremental sync method from from Query-Based to logical replication.

Changing sync methods triggers a re-sync of the entire connection.

Cause

This issue occurs when PostgreSQL freezes older transaction IDs during vacuuming, preventing us from using xmin to reliably detect incremental changes in the affected tables.