Tables Become Read-Only During HVR Activation

Issue

During HVR activation, source tables without a primary key become read-only, blocking UPDATE and DELETE operations until activation finishes.

Environment

• HVR 6
• Source: PostgreSQL version 16.0
• Target: Databricks
• Over 14,000 tables activated concurrently

Resolution

Before you start activation:

• Set REPLICA IDENTITY FULL on each table that doesn't have a primary key.
• Avoid using supplemental logging during activation for tables without a primary key, since it can block the source application.
• Confirm that the database user has permission to create publications.
• Check existing database sessions for locks that could cause deadlocks.
• Schedule activation during a period of low activity to minimize the impact on source applications.
• Prepare all required schema changes, including setting REPLICA IDENTITY, before you start activation.

Cause

This issue occurs when a source table doesn't have a primary key and its replica identity isn't set to FULL. PostgreSQL requires a replica identity to identify rows for UPDATE and DELETE operations during logical replication. Without one, PostgreSQL rejects these operations to prevent changes that it can't replicate reliably.