Overhead of pg_stat_statements and pg_stat_kcache

Postgres FM

Nikolay and Michael discuss the overhead of pg_stat_statements and pg_stat_kcache — mostly focusing on some interesting things Nikolay found while stress-testing some large spot instances up to and beyond 2m TPS(!)
Here are some links to things they mentioned:

• pg_stat_statements https://www.postgresql.org/docs/current/pgstatstatements.html
• pg_stat_kcache https://github.com/powa-team/pg_stat_kcache
• pg_stat_statements overhead estimate in pganalyze FAQs https://pganalyze.com/faq
• What is the performance impact of pg_stat_statements? (DBA Stack Exchange answer with several links) https://dba.stackexchange.com/questions/303503/what-is-the-performance-impact-of-pg-stat-statements
• Towards Millions TPS (blog post by Alexander Korotkov) https://akorotkov.github.io/blog/2016/05/09/scalability-towards-millions-tps
• Postgres.ai blog post with links to benchmarks https://postgres.ai/blog/20240127-postges-ai-bot
• postgresql_cluster https://github.com/vitabaks/postgresql_cluster
• pg_wait_sampling https://github.com/postgrespro/pg_wait_sampling
• pg_stat_kcache issue, discussion, and fast resolution https://github.com/powa-team/pg_stat_kcache/issues/41
• log_statement_sample_rate https://postgresqlco.nf/doc/en/param/log_statement_sample_rate/
• auto_explain.sample_rate https://www.postgresql.org/docs/current/auto-explain.html#id-1.11.7.14.5.3.13.1.3
• pg_stat_statements performance penalty on Intel much higher than on AMD https://gitlab.com/postgres-ai/postgresql-consulting/tests-and-benchmarks/-/issues/52

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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 brought to you by:

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

With special thanks to:

• Jessie Draws for the amazing artwork