Data Monitoring / PostgreSQL Monitoring
PostgreSQL: Replication write flush and replay
A standby is connected but returns stale query results. Compare the replication positions and replay timing with a known business transaction.
Environment and inputs: PostgreSQL 18 documentation baseline; views, extensions and permissions vary across versions and managed services.
Failure scenario
A standby is connected but returns stale query results. Confirm the cause before choosing a fix.
Evidence to collect
Compare the replication positions and replay timing with a known business transaction. Record the time, affected scope and a healthy comparison interval.
Fix the confirmed cause
Identify whether transport, persistence or replay is lagging before changing replica routing. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for replication write flush and replay using the same scope and a representative interval. Check that the symptom is resolved, expected records are present and downstream results are correct. If coverage, correctness or latency worsens, restore the recorded configuration through the agreed rollback process.
Scope and precautions
Prefer read-only access and limit queries to the relevant period or dataset. This example has not been tested on your systems. Test changes in an approved environment. Keep credentials and sensitive data out of shared evidence.