postgres pg_stat_statements setup guide

TL;DR

pgstatstatements needs sharedpreloadlibraries set and a server restart, then CREATE EXTENSION pgstatstatements in each database you want to monitor. It normalizes queries and tracks calls, total time, and mean time, which makes finding your worst queries a single query away. Reset stats with pgstatstatements_reset after deploys so old data does not skew the picture.

The query

postgres pg_stat_statements setup guide

Use this when

• you need to find the slowest or most frequent queries in Postgres
• you are setting up monitoring on a new database
• pgstatstatements views are empty and you do not know why

Not for

• seeing currently running queries, which is pgstatactivity
• query monitoring in other databases, which have their own tools

Steps

1. Add pgstatstatements to sharedpreloadlibraries and restart Postgres. The extension cannot load without the restart. Expected output: The server restarts and the library loads without errors.

2. Run CREATE EXTENSION pgstatstatements in every database you want stats for. It is per-database, not global. Expected output: The pgstatstatements view returns rows in each target database.

3. Find your worst queries: order by totalexectime desc for impact, or meanexectime desc for latency outliers. Expected output: You have a ranked list of queries by total and mean time.

4. Reset stats after deploys or tuning changes so you measure the new reality, not history. Expected output: Post-deploy numbers reflect only post-deploy traffic.

5. Set up a periodic snapshot of the view so you can compare week over week instead of relying on cumulative counters. Expected output: Historical snapshots exist for trend analysis.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst3NOo81OVFquOa8Jwo2A

Resolved from the public thread: https://vectle.com/posts/pst3NOo81OVFquOa8Jwo2A

Thread query: postgres pgstatstatements setup guide

TL;DR: pgstatstatements needs sharedpreloadlibraries set and a server restart, then CREATE EXTENSION pgstatstatements in each database you want to monitor. It normalizes queries and tracks calls, total time, and mean time, which makes finding your worst queries a single query away. Reset stats with pgstatstatements_reset after deploys so old data does not skew the picture.