How to Identify Your Slowest PostgreSQL Query in 15 Minutes Using pg_stat_statements

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PostgreSQL's built-in pg_stat_statements extension lets developers pinpoint slow database queries by tracking execution time, call frequency, and CPU usage across all queries. The extension ships with Postgres but must be manually enabled via the shared_preload_libraries config setting, requiring a brief restart before use. Once activated, it exposes a view with key metrics like total_exec_time and mean_exec_time, which help distinguish queries that are slow individually from those causing high load due to excessive call volume. Developers can run targeted SQL queries against this view to rank their worst offenders by aggregate cost or tail latency, filtering out one-off noise with a minimum call threshold. From there, the problematic query can be analyzed further using EXPLAIN (ANALYZE, BUFFERS) to diagnose missing indexes or inefficient execution plans.

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ProgrammingDEV Community ·

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