Postgres FM

Nikolay and Michael discuss denormalization in Postgres — when and why to denormalize things, and a couple of specific cases Nikolay came across recently.  Here are some links to things they mentioned:Denormalization https://en.wikipedia.org/wiki/DenormalizationOur episode on materialized views https://postgres.fm/episodes/materialized-viewsOur episode on data model trade-offs https://postgres.fm/episodes/data-model-trade-offsOur episode with Markus Winand https://postgres.fm/episodes/modern-sqlUniversal Relation Data Modelling Considered Harmful (blog post by Michael Stonebraker and Álvaro Hernández) https://www.enterprisedb.com/blog/universal-relation-data-modelling-considered-harmfulBoyce–Codd normal form https://en.wikipedia.org/wiki/Boyce%E2%80%93Codd_normal_formOur episode on slow count https://postgres.fm/episodes/slow-countpg_ivm https://github.com/sraoss/pg_ivmdenorm https://github.com/rivethealth/denormPostgres Materialized Views, The Timescale Way (blog post by David Kohn) https://www.timescale.com/blog/materialized-views-the-timescale-way/PgQ https://github.com/pgq/pgqDatabases, types, and the relational model (by C.J. Date and Hugh Darwen) https://www.dcs.warwick.ac.uk/~hugh/TTM/DTATRM.pdf~~~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 online Postgres communities — the ones they prefer, the types of conversations in each, and some other places to ask questions or follow news.  Here are some links to things they mentioned:https://www.postgresql.org/communityMailing lists https://www.postgresql.org/listIRC https://www.postgresql.org/community/ircSlack https://pgtreats.info/slack-inviteStack Overflow https://stackoverflow.com/questions/tagged/postgresDBA Stack Exchange https://dba.stackexchange.com/questions/tagged/postgresReddit https://www.reddit.com/r/PostgreSQLDiscord https://discord.gg/bW2hsax8WeHow to run ANALYZE (merge request discussion) https://gitlab.com/postgres-ai/postgresql-consulting/postgres-howtos/-/merge_requests/35This episode on YouTube https://postgresqlco.nfPlanet PostgreSQL https://planet.postgresql.orgPostgres Weekly https://postgresweekly.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 some cool things you can do with psql, the official CLI that ships with Postgres. Here are some links to things they mentioned:psql docs https://www.postgresql.org/docs/current/app-psql.html Our episode on psql vs GUIs https://postgres.fm/episodes/psql-vs-guispostgres_dba https://github.com/NikolayS/postgres_dbaOur episode on massive deletes https://postgres.fm/episodes/massive-deletesPostgres hacking session on \watch with limited number of loops https://www.youtube.com/watch?v=vTV8XhWf3mo pspg https://github.com/okbob/pspg Our episode on Postgres gotchas https://postgres.fm/episodes/postgres-gotchascurrent_setting() and set_config() docs https://www.postgresql.org/docs/current/functions-admin.html#FUNCTIONS-ADMIN-SETpsql tips (site by Lætitia Avrot) https://psql-tips.org~~~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 some Postgres Gotchas, things you might expect to work one way in fact working another way. Here are some links to things they mentioned:Our episode on NULLs https://postgres.fm/episodes/nulls-the-good-the-bad-the-ugly-and-the-unknownPostgres Gotchas (list by Ian Barwick) https://sql-info.de/postgresql/postgres-gotchas.htmlOur episode on slow count https://postgres.fm/episodes/slow-countDiscussion on X about major version upgrades and statistics https://x.com/samokhvalov/status/1844593601638260850Our episode on upgrades https://postgres.fm/episodes/upgradesStatistics Import and Export (commitfest entry which link to email thread) https://commitfest.postgresql.org/50/4538/vacuumdb https://www.postgresql.org/docs/current/app-vacuumdb.htmlvacuum_cost_delay https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-VACUUM-COST-DELAYZero-downtime Postgres schema migrations need lock_timeout and retries (blog post by Nikolay) https://postgres.ai/blog/20210923-zero-downtime-postgres-schema-migrations-lock-timeout-and-retriesPostgres Hacking 101: adding params, prevent_unqualified_deletes and prevent_unqualified_updates https://www.youtube.com/watch?v=samLkrC5xQA PostgREST suggestion to use pg-safeupdate https://docs.postgrest.org/en/v12/integrations/pg-safeupdate.html#pg-safeupdateDBOS (new company co-founded by Michael Stonebraker) https://www.dbos.dev~~~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 some more advanced topics around EXPLAIN, including some tips for complex query plans, some recent improvements, and an idea or two that might make it even better. Here are some links to things they mentioned:Michael’s solo episode on EXPLAIN basics https://postgres.fm/episodes/explainOur episode on auto_explain https://postgres.fm/episodes/auto_explainWhich cloud providers support auto_explain? (Blog post by Michael) https://www.pgmustard.com/blog/which-cloud-providers-support-auto-explainpsychopg https://www.psycopg.orgOur first episode on BUFFERS https://postgres.fm/episodes/buffers-by-defaultOur second episode on BUFFERS https://postgres.fm/episodes/buffers-ii-the-sequeltrack_io_timing https://www.postgresql.org/docs/current/runtime-config-statistics.html#GUC-TRACK-IO-TIMINGcompute_query_id https://www.postgresql.org/docs/current/runtime-config-statistics.html#GUC-COMPUTE-QUERY-ID EXPLAIN: beyond the basics (talk by Michael) https://www.youtube.com/watch?v=sGkSOvuaPs4~~~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 Alexander Kukushkin, PostgreSQL contributor and maintainer of Patroni, to discuss all things Patroni — what it is, how it works, recent improvements, and more.Here are some links to things they mentioned:Alexander Kukushkin https://postgres.fm/people/alexander-kukushkinPatroni https://github.com/patroni/patroniSpilo https://github.com/zalando/spilo Zalando Postgres Operator https://github.com/zalando/postgres-operatorCrunchy Data Postgres Operator https://github.com/CrunchyData/postgres-operatorSplit-brain https://en.wikipedia.org/wiki/Split-brain_(computing)repmgr https://github.com/EnterpriseDB/repmgrCloudNativePG https://github.com/cloudnative-pg/cloudnative-pgPatroni release notes https://patroni.readthedocs.io/en/latest/releases.htmlCitus & Patroni talk and demo by Alexander (at Citus Con 2023) https://www.youtube.com/watch?v=Mw8O9d0ez7E~~~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 fresh new Postgres 17 release! They cover several performance improvements, favourite new features, and some considerations for upgrading. Here are some links to things they mentioned:Postgres 17 release notes https://www.postgresql.org/docs/17/release-17.htmltransaction_timeout episode https://postgres.fm/episodes/transaction_timeoutVACUUM improvements discussed towards end of episode with Melanie Plageman https://postgres.fm/episodes/getting-started-with-benchmarkingB-tree improvements discussed in episdode with Peter Geoghegan https://postgres.fm/episodes/skip-scanAs Rails developers, why we are excited about PostgreSQL 17 (blog post by Benoit Tigeot) https://benoittgt.github.io/blog/postgres_17_rails/ Real World Performance Gains With Postgres 17 B-tree Bulk Scans (blog post by Brandur Leach) https://www.crunchydata.com/blog/real-world-performance-gains-with-postgres-17-btree-bulk-scansMERGE RETURNING came up towards end of episode with Haki Benita https://postgres.fm/episodes/get-or-createuuid_extract_timestamp and uuid_extract_version functions https://www.postgresql.org/docs/current/functions-uuid.htmlEpisode on UUID https://postgres.fm/episodes/uuidPartitioning by ULID https://postgres.fm/episodes/partitioning-by-ulidWhy Upgrade? (site by depesz) https://why-upgrade.depesz.comWhy we spent the last month eliminating PostgreSQL subtransactions (GitLab blog post) https://about.gitlab.com/blog/2021/09/29/why-we-spent-the-last-month-eliminating-postgresql-subtransactionsSynchronization of sequences to subscriber (patch that needs review!)  https://commitfest.postgresql.org/49/5111~~~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 planning time in Postgres — what it is, how to spot issues, its relationship to things like partitioning, and some tips for avoiding issues. Here are some links to things they mentioned:Query Planning (docs) https://www.postgresql.org/docs/current/runtime-config-query.htmlAre there limits to partition counts? (Blog post by depesz) https://www.depesz.com/2021/01/17/are-there-limits-to-partition-countsNikolays recent experiment https://postgres.ai/chats/01920004-a982-7896-b8cb-dfd2406359b0PgBouncer now supports prepared statements https://github.com/pgbouncer/pgbouncer/releases/tag/pgbouncer_1_21_0“The year of the lock manager’s revenge” (from blog post by Jeremy Schneider) https://ardentperf.com/2024/03/03/postgres-indexes-partitioning-and-lwlocklockmanager-scalabilitypg_stat_statements.track_planning https://www.postgresql.org/docs/current/pgstatstatements.html#id-1.11.7.42.9.2.4.1.3pg_hint_plan https://github.com/ossc-db/pg_hint_plan~~~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 why counting can be slow in Postgres, and what the options are for counting things quickly at scale. Here are some links to things they mentioned:Aggregate functions (docs) https://www.postgresql.org/docs/current/functions-aggregate.htmlPostgREST https://github.com/PostgREST/postgrest Get rid of count by default in PostgREST https://github.com/PostgREST/postgrest/issues/273 Faster PostgreSQL Counting (by Joe Nelson on the Citus blog) https://www.citusdata.com/blog/2016/10/12/count-performance Our episode on Index-Only Scans https://postgres.fm/episodes/index-only-scansPostgres HyperLogLog https://github.com/citusdata/postgresql-hllOur episode on Row estimates https://postgres.fm/episodes/row-estimates Our episode about dangers of NULLs https://postgres.fm/episodes/nulls-the-good-the-bad-the-ugly-and-the-unknown Aggregate expressions, including FILTER https://www.postgresql.org/docs/current/sql-expressions.html#SYNTAX-AGGREGATESSpread writes for counter cache (tip from Tobias Petry) https://x.com/tobias_petry/status/1475870220422107137pg_ivm extension (Incremental View Maintenance) https://github.com/sraoss/pg_ivm pg_duckdb announcement https://motherduck.com/blog/pg_duckdb-postgresql-extension-for-duckdb-motherduckOur episode on Queues in Postgres https://postgres.fm/episodes/queues-in-postgresOur episode on Real-time analytics https://postgres.fm/episodes/real-time-analyticsClickHouse acquired PeerDB https://clickhouse.com/blog/clickhouse-acquires-peerdb-to-boost-real-time-analytics-with-postgres-cdc-integrationTimescale Continuous Aggregates https://www.timescale.com/blog/materialized-views-the-timescale-wayTimescale editions https://docs.timescale.com/about/latest/timescaledb-editionsLoose indexscan https://wiki.postgresql.org/wiki/Loose_indexscan~~~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 Peter Geoghegan, major contributor and committer to Postgres, to discuss adding skip scan support to PostgreSQL over versions 17 and 18. Here are some links to things they mentioned:Peter Geoghegan https://postgres.fm/people/peter-geogheganPeter’s previous (excellent) interview on Postgres TV https://www.youtube.com/watch?v=iAPawr1DxhMEfficient Search of Multidimensional B-Trees (1995 paper by Harry Leslie, Rohit Jain, Dave Birdsall, and Hedieh Yaghmai) https://vldb.org/conf/1995/P710.PDFIndex Skip Scanning in Oracle https://oracle-base.com/articles/9i/index-skip-scanningPeter’s introductory email to the hackers mailing list about adding skip scan https://www.postgresql.org/message-id/CAH2-Wzmn1YsLzOGgjAQZdn1STSG_y8qP__vggTaPAYXJP+G4bw@mail.gmail.comLoose Indexscan versus Index Skip Scan (PostgreSQL wiki) https://wiki.postgresql.org/wiki/Loose_indexscanTom Lane will be on the Talking Postgres podcast on October 9th https://aka.ms/TalkingPostgres-Ep20-calBenoit Tigeot feedback and repro (originally reported via Slack) https://gist.github.com/benoittgt/ab72dc4cfedea2a0c6a5ee809d16e04d?permalink_comment_id=4597410#gistcomment-4597410Summary video and blog post about the v17 work by Lukas from pganalyze (not mentioned but great) https://pganalyze.com/blog/5mins-postgres-17-faster-btree-index-scansUnderstanding HNSW + filtering (pgvector repo discussion) https://github.com/pgvector/pgvector/issues/259btree_gin https://www.postgresql.org/docs/current/btree-gin.html~~~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