Upgrading a 5TB PostgreSQL Environment Under Replication Constraints

Upgrade a PostgreSQL 12 environment consisting of a primary and standby database (~5TB) under significant constraints:

• Limited available disk space (no capacity for parallel rebuild)
• Tight maintenance window
• Requirement to maintain replication and data integrity
• Dependency on repmgr compatibility, requiring a staged upgrade path

A direct upgrade to the target version was not feasible due to third party replication module compatibilty constraints.

Designed and executed a controlled, staged upgrade strategy aligned with both operational constraints and replication module requirements.

Key elements included:

• Performed upgrade in stages (12 → 15 → 17) to maintain compatibility with repmgr
• Selection of an in-place upgrade approach to avoid additional storage requirements
• Careful coordination of upgrade steps between primary and standby systems
• Validation of configuration, extensions, and compatibility
• Controlled execution with defined procedures to ensure consistency

• Successful upgrade from PostgreSQL 12 to version 17
• Replication maintained and re-established cleanly at each stage
• Upgrade completed within the available time and storage constraints
• Stable and reliable post-upgrade environment