PG-LONGTX-001 · Long-running or idle-in-transaction sessions

Severity	Confidence	Permission	Applies to
High	Confirmed	pg_monitor (pg_read_all_stats)	PostgreSQL 14+, RDS, Aurora, Azure Flexible

What it checks

Client sessions in pg_stat_activity with a transaction open for more than 5 minutes (max_tx_s: 300), or in idle in transaction for more than 60 seconds (idle_tx_s: 60). Shows who (user, application, client address) and the last query.

Why it matters

The oldest open transaction sets the horizon for vacuum across the whole cluster: dead rows newer than it can't be removed, so tables and indexes bloat. It may also hold locks that block other sessions.

Next action

Find the application behind each pid. idle in transaction almost always means a missing COMMIT or a connection returned to the pool mid-transaction. As a safety net:

ALTER SYSTEM SET idle_in_transaction_session_timeout = '10min';
SELECT pg_reload_conf();

Limitations

A snapshot only sees transactions open at the moment of the check.