Postgres FM

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 

Michael and Nikolay are joined by Lukas Eder, the creator of jOOQ, to discuss what it is, some nice developer experience features it has, and some fun things he's come across from a Postgres perspective. Here are some links to things they mentioned:Lukas Eder https://postgres.fm/people/lukas-ederjOOQ https://www.jooq.org/ DSL https://en.wikipedia.org/wiki/Domain-specific_language SQL Dialects https://www.jooq.org/javadoc/latest/org.jooq/org/jooq/SQLDialect.htmlMERGE https://www.postgresql.org/docs/current/sql-merge.html match_recognize https://modern-sql.com/feature/match_recognize JOOQ, joy of SQL (talk by Kevin Davin) https://www.youtube.com/watch?v=8Ej47GZX9D8  BUFFERS enabled for EXPLAIN ANALYZE by default (commit for Postgres 18) https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=c2a4078ebad71999dd451ae7d4358be3c9290b07 PostGIS https://postgis.net/ 10 SQL Tricks That You Didn’t Think Were Possible (blog post by Lukas) https://blog.jooq.org/10-sql-tricks-that-you-didnt-think-were-possible/ jOOQ questions on Stack Overflow https://stackoverflow.com/questions/tagged/jooq Our episode on NULLs https://postgres.fm/episodes/nulls-the-good-the-bad-the-ugly-and-the-unknown ~~~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 "Column Tetris" — what it is, why it matters, how to order columns for new tables, and how to re-organise existing ones. Here are some links to things they mentioned:“Column Tetris” by Erwin Brandstetter on Stack Overflow  https://stackoverflow.com/questions/2966524/calculating-and-saving-space-in-postgresql/7431468#7431468Data Types https://www.postgresql.org/docs/current/datatype.htmlOrioleDB beta7 benchmarks https://www.orioledb.com/blog/orioledb-beta7-benchmarkspg_hexedit https://github.com/petergeoghegan/pg_hexeditSaving Space Basically for Free (blog post by James Coleman from Braintree) https://medium.com/paypal-tech/postgresql-at-scale-saving-space-basically-for-free-d94483d9ed9aOrdering Table Columns (GitLab https://docs.gitlab.com/ee/development/database/ordering_table_columns.htmlpostgres_dba alignment padding query https://github.com/NikolayS/postgres_dba/blob/master/sql/p1_alignment_padding.sqlGood explanation from Marco Slot of how alignment was used to fix a recent issue https://x.com/marcoslot/status/1858132850383421570pg_repack feature request discussion https://github.com/reorg/pg_repack/issues/101Our episode on bloat (with Chelsea Dole) https://postgres.fm/episodes/bloatOptimizing table layout for maximum efficiency (blog post by Renato Massaro) https://r.ena.to/blog/optimizing-postgres-table-layout-for-maximum-efficiency~~~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 the track_planning parameter of pg_stat_statements — what it is, how it affects performance, and when or whether you should switch it on. Here are some links to things they mentioned:pg_stat_statements.track_planning https://www.postgresql.org/docs/current/pgstatstatements.html#id-1.11.7.40.9.2.4.1.3Our episode about pg_stat_statements https://postgres.fm/episodes/pg_stat_statementsPostgreSQL 13.0 release notes https://www.postgresql.org/docs/release/13.0/track_planning causing performance regression (thread on hackers during v13 beta) https://www.postgresql.org/message-id/flat/2895b53b033c47ccb22972b589050dd9%40EX13D05UWC001.ant.amazon.comOur episode on 4 million TPS https://postgres.fm/episodes/four-million-tpsObserver effect in pg_stat_statements and pg_stat_kcache (Postgres TV Hacking session with Andrey and Kirk) https://www.youtube.com/live/wHMNX-fHb2A?si=DPgmrPaSpPF6DxuS~~~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 Gülçin Yıldırım Jelínek and Robert Haas to discuss both the technical question of whether or not pg_dump is a backup tool, as well as the tone and intent behind the statement "pg_dump is not a backup tool". Here are some links to things they mentioned:Gülçin Yıldırım Jelínek https://postgres.fm/people/gulcin-yildirim-jelinekRobert Haas https://postgres.fm/people/robert-haasWhy you should upgrade PostgreSQL today (blog post by Gülçin) https://xata.io/blog/cve-2024-7348-postgres-upgradeIf pg_dump is not a backup tool, what is? (blog post by Gülçin) https://xata.io/blog/pgdump-is-not-a-backup-toolIs pg_dump a backup tool? (blog post by Robert) https://rhaas.blogspot.com/2024/10/is-pgdump-backup-tool.html?m=1Why pg_dump is amazing (blog post by Robert) https://rhaas.blogspot.com/2024/11/why-pgdump-is-amazing.htmlAvoid too prominent use of "backup" on pg_dump man page (commit by Peter Eisentraut) https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=4f29394ea941f688fd4faf7260d2c198931ca797Is pg_dump a backup tool? (poll by Nikolay with options Yes / No / Define backup) https://x.com/samokhvalov/status/1847015453056786771What's the best way to make a backup (a recent example discussion on Reddit) https://www.reddit.com/r/PostgreSQL/comments/1gu4r05/whats_the_best_way_to_make_a_backup/Hackers mailing list https://www.postgresql.org/list/pgsql-hackers/ Praise, Criticism, and Dialogue (blog post by Robert) https://rhaas.blogspot.com/2023/12/praise-criticism-and-dialogue.html Out-of-cycle release scheduled for November 21, 2024 https://www.postgresql.org/about/news/out-of-cycle-release-scheduled-for-november-21-2024-2958/ pgBackRest https://github.com/pgbackrest/pgbackrest Barman https://github.com/EnterpriseDB/barman Our previous episode on backups https://postgres.fm/episodes/backups ~~~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 append-only tables in Postgres — what they are, some unique challenges they bring, and some options for compressing / removing / offloading the data eventually. Here are some links to things they mentioned:Append-only https://en.wikipedia.org/wiki/Append-onlyOur episode on BRIN indexes https://postgres.fm/episodes/brin-indexesTips to Improve Insert Performance https://www.timescale.com/blog/13-tips-to-improve-postgresql-insert-performance/ Our episode on WAL and checkpoint tuning https://postgres.fm/episodes/wal-and-checkpoint-tuningautovacuum_vacuum_insert_scale_factor https://www.postgresql.org/docs/current/runtime-config-autovacuum.html#GUC-AUTOVACUUM-VACUUM-INSERT-SCALE-FACTOR Our episode about compression https://postgres.fm/episodes/compressionNew project announced recently called BemiDB https://x.com/samokhvalov/status/1854726389603484145pg_tier https://github.com/tembo-io/pg_tier~~~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