Christophe Pettus clarifies that max_standby_streaming_delay and max_standby_archive_delay control replication lag, not query execution time. Once the allocated delay budget is exhausted, standby queries are canceled immediately, regardless of their duration. This distinction is critical for tuning read replicas to handle heavy analytical workloads without unnecessary aborts.
- These GUCs manage replication lag, not query runtime on the standby.
- Queries are canceled immediately once the delay budget is exceeded.
- Long-running analytical queries on standbys are vulnerable to cancellation.
- Tune these parameters based on acceptable replication lag, not query length.