Mean vs p99

Nikolay and Michael discuss looking at queries by mean time — when it makes sense, why ordering by a percentile (like p99) might be better, and the merits of approximating percentiles in pg_stat_statements using the standard deviation column.

Here are some links to things they mentioned:

• Approximate the p99 of a query with pg_stat_statements (blog post by Michael) https://www.pgmustard.com/blog/approximate-the-p99-of-a-query-with-pgstatstatements
• pg_stat_statements https://www.postgresql.org/docs/current/pgstatstatements.html
• Our episode about track_planning https://postgres.fm/episodes/pg-stat-statements-track-planning
• pg_stat_monitor https://github.com/percona/pg_stat_monitor
• statement_timeout https://www.postgresql.org/docs/current/runtime-config-client.html#GUC-STATEMENT-TIMEOUT

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What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!

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Postgres FM is produced by:

• Michael Christofides, founder of pgMustard
• Nikolay Samokhvalov, founder of Postgres.ai

With credit to:

• Jessie Draws for the elephant artwork