Check PostgreSQL Sequences for Overflow Risk
Shows how close each sequence is to its data type limit. A sequence that hits the integer limit causes a production outage.
SELECT schemaname, sequencename, data_type, last_value, max_value,
round(100.0 * last_value / max_value, 2) AS pct_used
FROM pg_sequences
WHERE last_value IS NOT NULL
ORDER BY pct_used DESC
LIMIT 20;Alert when a sequence reaches 80% of its maximum value. Migrate `integer` primary keys to `bigint` before wraparound occurs.
- This script is designed for read-only diagnostics; it does not alter schema or modify data directly.
- Prior to executing on production systems under high load, verify the target database version (Min. Version: 10).
- Exercise caution with mutating actions (e.g., terminating sessions or dropping indexes) referenced in the notes section.
Engineering Triad: Related Runbooks & Incident Response
Which production incidents and emergency drills execute this script as a diagnosis step?
Other POSTGRESQL Diagnostic Scripts
View All (100)Find Long-Running Queries and Idle-in-Transaction Sessions in PostgreSQL
Lists queries running longer than a minute, their wait events, and idle-in-transaction sessions that block vacuum. The first script to run during a performance incident.
PostgreSQL Lock Chain: Who Is Blocking Whom?
Uses pg_blocking_pids to pair blocked and blocking sessions with their queries and wait times. Shows the root cause of a lock chain in seconds.
PostgreSQL Dead Tuples, Bloat and Autovacuum Health Check
Shows dead tuple ratio and last vacuum/analyze times per table. Helps you find tables where autovacuum settings are not keeping up.
Find Unused Indexes in PostgreSQL
Lists never-scanned indexes that are neither unique nor primary keys, with their sizes. Surfaces cleanup candidates to cut write overhead and disk usage.