Postgres Logical Replication for Reporting Replicas: The Gotchas the Tutorials Skip

Postgres logical replication appears simple via CREATE PUBLICATION and CREATE SUBSCRIPTION, often leading users to overlook physical replication. However, implementing it for real reporting replicas—where analysts run ad-hoc queries on different major versions with read-tuned indexes—reveals four critical gotchas omitted from standard tutorials. While physical replication ships raw WAL for byte-for-byte consistency across entire clusters, logical replication offers flexibility that introduces distinct, avoidable challenges when facing actual production reporting workloads in the field.