Show Notes
Nik and Michael discuss query plan flips in Postgres — what they are, some causes, mitigations, longer term solutions, and the recent outage at Clerk.
Here are some links to things they mentioned: Recent postmortem from Clerk https://clerk.com/blog/2026-02-19-system-outage-postmortem The real cost of random I/O (blog post by Tomas Vondra) https://vondra.me/posts/the-real-cost-of-random-io autovacuum_analyze_scale_factor https://www.postgresql.org/docs/current/runtime-config-vacuum.html#GUC-AUTOVACUUM-ANALYZE-SCALE-FACTOR default_statistics_target https://www.postgresql.org/docs/current/runtime-config-query.html#GUC-DEFAULT-STATISTICS-TARGET pg_hint_plan https://github.com/ossc-db/pg_hint_plan Aurora PostgreSQL query plan management https://docs.aws.amazon.comAmazonRDS/latest/AuroraUserGuide/AuroraPostgreSQL.Optimize.Start.html pg_stat_plans https://github.com/pganalyze/pg_stat_plans pg_plan_alternatives https://jnidzwetzki.github.io/2026/03/04/pg-plan-alternatives.html Waiting for Postgres 19: Better Planner Hints with Path Generation Strategies https://pganalyze.com/blog/5mins-postgres-19-better-planner-hints
~~~ 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!
~~~ 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
More from Postgres FM
Nik and Michael are joined by Álvaro Hernández to discuss sharding Postgres with Citus and StackGres, especially the new query router support that has been added very recently.
Nik and Michael are joined by Salma El-Sayed and Kirk Wolak to discuss their in-progress and very ambitious Google Summer of Code project around adding Btree Merge support to Postgres.
Nik and Michael are joined by Sai Srirampur to discuss ClickHouse's new managed Postgres service.
Nik and Michael discuss hot_standby_feedback — what it controls, whether and when read replicas should be changed to on, and other settings you can change to help too.
Nik and Michael are joined by Shaun Thomas to discuss estimating work_mem, memory management in general, and writing an extension to help.