Postgres FM

Nikolay and Michael discuss GIN indexes in Postgres — what they are, what they're used for, and some limitations to be aware of. Here are some links to things they mentioned:GIN Indexes https://www.postgresql.org/docs/current/gin.htmlGeneralized Search Trees for Database Systems (Hellerstein, Naughton, Pfeffer) https://dsf.berkeley.edu/papers/vldb95-gist.pdf RUM extension https://pgxn.org/dist/rum/1.1.0/Understanding Postgres GIN Indexes: The Good and the Bad (Lukas Fittl) https://pganalyze.com/blog/gin-index~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith credit to:Jessie Draws for the elephant artwork

Nikolay and Michael use a recent "best practices" article as a prompt — giving a few tips each on the topics mentioned, like schema design, performance, backups, and more. Here are some links to things they mentioned:7 Crucial PostgreSQL Best Practices (recent blog post) https://speakdatascience.com/postgresql-best-practices“Don't do this” episode https://postgres.fm/episodes/dont-do-thisArticle discussion on Hacker News https://news.ycombinator.com/item?id=42992913Mozilla’s SQL Style Guide https://docs.telemetry.mozilla.org/concepts/sql_style“SQL vs NoSQL” episode with Franck Pachot https://postgres.fm/episodes/sql-vs-nosqlHA episode https://postgres.fm/episodes/high-availability ~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith credit to:Jessie Draws for the elephant artwork

Nikolay and Michael discuss the CREATE STATISTICS feature in Postgres — what it's for, how often it's used, and how to spot cases where it would help.  Here are some links to things they mentioned:CREATE STATISTICS https://www.postgresql.org/docs/current/sql-createstatistics.htmlcitext https://www.postgresql.org/docs/current/citext.htmlStatistics Used by the Planner https://www.postgresql.org/docs/current/planner-stats.htmldefault_statistics_target https://www.postgresql.org/docs/current/runtime-config-query.html#GUC-DEFAULT-STATISTICS-TARGETTomáš Vondra on Postgres TV https://www.youtube.com/watch?v=8la-OWfD3VIRecent commit to Postgres 18 for pg_upgrade https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=1fd1bd871012732e3c6c482667d2f2c56f1a9395Multivariate Statistics Examples https://www.postgresql.org/docs/current/multivariate-statistics-examples.htmlExtended statistics (README) https://github.com/postgres/postgres/blob/master/src/backend/statistics/READMEHow we used Postgres extended statistics to achieve a 3000x speedup (blog post by Jared Rulison) https://medium.com/affinity-engineering/how-we-used-postgres-extended-statistics-to-achieve-a-3000x-speedup-ea93d3dcdc61~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith credit to:Jessie Draws for the elephant artwork

Nikolay and Michael are joined by Franck Pachot to discuss SQL vs NoSQL — did Franck change teams by joining MongoDB, normalisation vs denormalisation, developer experience, NULLs, and more! Here are some links to things they mentioned:Franck Pachot https://postgres.fm/people/franck-pachotFranck's workshop at PGConf India https://pgconf.in/conferences/pgconfin2025/program/proposals/958 PostgreSQL Conference Germany https://2025.pgconf.de"Schema Later" Considered Harmful by Michael Stonebraker and Álvaro Hernández https://www.enterprisedb.com/blog/schema-later-considered-harmfulComparison of JOINS by Michael Stonebraker and Álvaro Hernández https://www.enterprisedb.com/blog/comparison-joins-mongodb-vs-postgresql Franck’s post about why he joined MongoDB https://www.linkedin.com/pulse/2025-im-joining-mongodb-franck-pachot-e4shfEdgeDB https://www.edgedb.comNikolay’s tweet about a recent issue with NULLs https://x.com/samokhvalov/status/1889078097124999272PartiQL https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ql-reference.htmlFerretDB https://www.ferretdb.comDocumentDB https://github.com/microsoft/documentdb~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork 

Nikolay and Michael return to the topic of BUFFERS for the third (and final?) time! They discuss the news that it'll be on by default with EXPLAIN ANALYZE in Postgres 18, and what effect that might have.  Here are some links to things they mentioned:Our first BUFFERS episode https://postgres.fm/episodes/buffers-by-defaultOur second BUFFERS episode https://postgres.fm/episodes/buffers-ii-the-sequelBUFFERS enabled for EXPLAIN ANALYZE by default (commit for Postgres 18) https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=c2a4078ebad71999dd451ae7d4358be3c9290b07https://explain.depesz.com/historyLatency Numbers Every Programmer Should Know https://gist.github.com/jboner/2841832Twitter conversation about flushing caches https://x.com/prochazkafilip/status/1881655337499205736pg_buffercache_evict https://www.postgresql.org/docs/current/pgbuffercache.html#PGBUFFERCACHE-PG-BUFFERCACHE-EVICTHow to compare the quality of SQL query plans (blog post by Andrei Lepikhov) https://danolivo.substack.com/p/whose-optimisation-is-betterWe were added as PostgreSQL Contributors! https://www.postgresql.org/about/news/new-postgresql-contributors-3006~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork 

Nikolay and Michael discuss a couple of surprising ways read queries (selects) can cause writes (shared buffers dirtied) in Postgres. Here are some links to things they mentioned:Reads causing writes in Postgres (post by Alex Jesipow) https://jesipow.com/blog/postgres-reads-cause-writes/Exploring how SELECT queries can produce disk writes (post by Nikolay Sivko) https://blog.okmeter.io/postgresql-exploring-how-select-queries-can-produce-disk-writes-f36c8bee6b6f Hint Bits (wiki) https://wiki.postgresql.org/wiki/Hint_Bitspg_stat_statements https://www.postgresql.org/docs/current/pgstatstatements.html pg_stat_kcache https://github.com/powa-team/pg_stat_kcache pg_wait_sampling https://github.com/postgrespro/pg_wait_sampling BUFFERS by default (episode 4!) https://postgres.fm/episodes/buffers-by-default Page layout (docs) https://www.postgresql.org/docs/current/storage-page-layout.html From Reddit (user merlinm), PD_ALL_VISIBLE may be a third case https://www.reddit.com/r/PostgreSQL/comments/1hjuyfn/comment/m3e6e7v/ Coroot https://coroot.com/ ~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork 

Nikolay and Michael discuss adding constraints in an online fashion, using NOT VALID and then VALIDATE CONSTRAINT. Here are some links to things they mentioned:ADD table_constraint NOT VALID  https://www.postgresql.org/docs/current/sql-altertable.html#SQL-ALTERTABLE-DESC-ADD-TABLE-CONSTRAINTOur episode on zero-downtime migrations https://postgres.fm/episodes/zero-downtime-migrationsVALIDATE CONSTRAINT https://www.postgresql.org/docs/current/sql-altertable.html#SQL-ALTERTABLE-DESC-VALIDATE-CONSTRAINTALTER TABLE notes https://www.postgresql.org/docs/current/sql-altertable.html#SQL-ALTERTABLE-NOTESpgroll https://github.com/xataio/pgroll~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork 

Michael and Nikolay are joined by Antonín Houska to discuss pg_squeeze — what it is, how it started, some of its features, and hopes of getting the functionality into core. Here are some links to things they mentioned:Antonín Houska https://postgres.fm/people/antonin-houskapg_squeeze https://github.com/cybertec-postgresql/pg_squeezeCybertec https://www.cybertec-postgresql.compg_repack https://github.com/reorg/pg_repackIntroducing pg_squeeze (by Kaarel Moppel) https://www.cybertec-postgresql.com/en/introducing-pg_squeeze-a-postgresql-extension-to-auto-rebuild-bloated-tablespg_squeeze is included in the PostgreSQL APT packages https://wiki.postgresql.org/wiki/Aptpg_squeeze is included in the PostgreSQL Yum packages https://yum.postgresql.orgpg_rewrite https://github.com/cybertec-postgresql/pg_rewriteVACUUM FULL / CLUSTER CONCURRENTLY patch https://commitfest.postgresql.org/51/5117~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork 

Michael and Nikolay are joined by Joe Sciarrino and Jelte Fennema-Nio to discuss pg_duckdb — what it is, how it started, what early users are using it for, and what they're working on next. Here are some links to things they mentioned:Joe Sciarrino https://postgres.fm/people/joe-sciarrinoJelte Fennema-Nio https://postgres.fm/people/jelte-fennema-niopg_duckdb https://github.com/duckdb/pg_duckdbHydra https://www.hydra.soMotherDuck https://motherduck.comThe problems and benefits of an elephant with a beak (lightning talk by Jelte) https://www.youtube.com/watch?v=ogvbKE4fw9A&list=PLF36ND7b_WU4QL6bA28NrzBOevqUYiPYq&t=1073spg_duckdb announcement post (by Jordan and Brett from MotherDuck) https://motherduck.com/blog/pg_duckdb-postgresql-extension-for-duckdb-motherduckpg_duckdb 0.2 release https://github.com/duckdb/pg_duckdb/releases/tag/v0.2.0~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork 

Nikolay and Michael discuss Row Level Security in Postgres, focussing on the performance side effects and some tips to avoid (or minimize) them. Here are some links to things they mentioned:Row Security Policies (docs) https://www.postgresql.org/docs/current/ddl-rowsecurity.html7+ million Postgres tables (recent talk by Kailash Nadh) https://www.youtube.com/watch?v=xhi5Q_wL9i0Row Level Security guide (Supabase docs) https://supabase.com/docs/guides/database/postgres/row-level-securitycurrent_setting function https://www.postgresql.org/docs/current/functions-admin.html#id-1.5.8.34.3.6.2.2.1.1.1.1Our slow count episode https://postgres.fm/episodes/slow-countRLS Performance and Best Practices (gist from Gary Austin) https://github.com/orgs/supabase/discussions/14576Everything you need to know about Postgres Row Level Security (talk by Paul Copplestone) https://www.youtube.com/watch?v=vZT1Qx2xUCoBUFFERS enabled for EXPLAIN ANALYZE by default (commit for Postgres 18) https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=c2a4078ebad71999dd451ae7d4358be3c9290b07Add UUID version 7 generation function (commit for Postgres 18) https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=78c5e141e9c139fc2ff36a220334e4aa25e1b0ebPostgres hacking session with Andrey and Kirk (for UUIDv7): https://www.youtube.com/watch?v=YPq_hiOE-N8~~~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 pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork