Data Monitoring / PostgreSQL Monitoring
PostgreSQL: Blocking session relationships
Many PostgreSQL sessions wait on locks during a deployment. Use pg_blocking_pids with activity evidence and capture the head transaction's context.
Environment and inputs: PostgreSQL 18 documentation baseline; views, extensions and permissions vary across versions and managed services.
Failure scenario
Many PostgreSQL sessions wait on locks during a deployment. Confirm the cause before choosing a fix.
Evidence to collect
Use pg_blocking_pids with activity evidence and capture the head transaction's context. Record the time, affected scope and a healthy comparison interval.
Worked diagnostic example
Read-only PostgreSQL blocker lookup for the current database.
SELECT pid, application_name, pg_blocking_pids(pid) AS blockers
FROM pg_stat_activity
WHERE datname = current_database()
AND cardinality(pg_blocking_pids(pid)) > 0;Fix the confirmed cause
Coordinate resolution with the transaction owner and retest the affected operation without unnecessary session termination. Write the expected result first. Change one relevant setting at a time.
Check the result and hand over
Repeat the check for blocking session relationships 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.