PG-TOPQUERY-001 · A single query dominates execution time

Severity	Confidence	Permission	Applies to
Medium	Hint	pg_monitor (pg_read_all_stats) + pg_stat_statements	PostgreSQL 14+, RDS, Aurora, Azure Flexible

What it checks

Top-level statements in pg_stat_statements. Reported when the most expensive query takes at least 40% of the total execution time (dominant_pct) and the total is at least 60 s (min_total_s). The evidence lists the top 5 with share, calls, mean time, rows per call and cache hit ratio.

Without the extension the rule reports No data and points to PG-PGSS-001.

Why it matters

When one query dominates, fixing it is the change with the highest return.

Next action

EXPLAIN (ANALYZE, BUFFERS) <query with real parameters>;

Look for sequential scans on large tables, row estimates far from reality, and sorts or hashes spilling to disk. Also check whether it runs more often than the application needs (a low rows per call with huge calls suggests an N+1 pattern).

Limitations

Totals accumulate since the last pg_stat_statements_reset() or restart, so you can't tell when a query started dominating. Without pg_read_all_stats, other users' query texts show as <insufficient privilege>.