Estimating work_mem

Tip: watch on YouTube. Since episode 193, the video shows charts and illustrations as we talk. https://www.youtube.com/watch?v=7oeAAqU00zk Nik and Kirk are joined by Álvaro Hernández to discuss how Postgres in containers gets its extensions: a fat image with all of them, extensions downloaded at run time, or StackGres Containers, built on DOCIR (Dynamic OCI Registry), which composes an image with only the extensions you ask for, on demand. They also discuss what this means for security, pinning versions, and major upgrades. Here are some links to things they mentioned: Times are podcast times of the first mention.Main link[00:18:54] Dynamic containers for PostgreSQL: what we measured (DBLab Forge brief, PostgresAI) https://console.postgres.ai/shared/brief/c501d438-b872-4705-89a6-bdab30ea1680Álvaro and StackGres[00:00:25] Álvaro Hernández https://postgres.fm/people/alvaro-hernandez-tortosa[00:01:16] StackGres Containers (public beta; the images come from the registry host sgcr.io, and the demo used sgcr.dev, a dev instance) https://stackgres.io/containers[00:14:52] StackGres https://stackgres.io[00:20:55] PostgreSQL extensions in StackGres, loaded into running pods (docs) https://stackgres.io/doc/latest/features/extensions/[00:24:28] StackGres extensions cache, experimental (docs) https://stackgres.io/doc/latest/administration/extensions/cache/[01:04:08] Why Postgres extensions should be packaged and distributed as OCI images (Álvaro Hernández, 2024) https://ongres.com/blog/why-postgres-extensions-should-be-distributed-and-packaged-as-oci-images/Episodes[00:00:25] Our previous episode with Álvaro: Citus + StackGres https://postgres.fm/episodes/citus-stackgresHacking sessions[00:31:33] Hacking Postgres sessions with Andrey, Kirk and Nik (YouTube playlist, PostgresTV) https://www.youtube.com/playlist?list=PLH8y1BNPAKjKDdJA7sDmFWUkbbYux3TRzPostgres and extensions[00:38:51] extension_control_path, new in Postgres 18 (docs) https://www.postgresql.org/docs/18/runtime-config-client.html#GUC-EXTENSION-CONTROL-PATH[00:50:56] pg_background https://github.com/vibhorkum/pg_background[00:50:58] plsh (Peter Eisentraut) https://github.com/petere/plsh[01:02:58] PGXN, the PostgreSQL Extension Network https://pgxn.org[01:04:40] POC: Distributing Trunk binaries via OCI (David E. Wheeler, 2024) https://justatheory.com/2024/06/trunk-oci-poc/[01:05:12] Anarchy in the Database: a survey and evaluation of DBMS extensibility (Kim, Slot, Andersen, Pavlo, VLDB 2025; tests extensions in pairs) https://www.vldb.org/pvldb/vol18/p1962-kim.pdfContainers[00:01:22] OCI image format specification https://github.com/opencontainers/image-spec[00:41:19] Spilo (Zalando), one Postgres image with several major versions https://github.com/zalando/spilo[01:05:43] Testcontainers, PostgreSQL module https://testcontainers.com/modules/postgresql/Other[00:36:32] Mitchell Hashimoto on never updating dependencies unless it breaks (post on X, 2026-05-20) https://x.com/mitchellh/status/2057171518027887035~~~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 PostgresAIWith credit to:Jessie Draws for the elephant artworkIntro and outro music: our own arrangement of Apple Loops from GarageBand (royalty-free under the GarageBand licence)

Tip: watch on YouTube. Since episode 193, the video shows charts and illustrations as we talk. https://www.youtube.com/watch?v=gf8e3JkQ_8M Nik is joined by Kirk Wolak to discuss what a random UUIDv4 primary key really costs compared with a time-ordered UUIDv7 or an int8 key on Postgres 18 — index size, WAL and full-page writes, insert rate once the index outgrows memory — and what DBLab Forge found when it ran the experiment. Here are some links to things they mentioned: Times are podcast times of the first mention.Main link[00:00:34] UUIDv4 vs UUIDv7 vs int8 primary keys on Postgres 18 (DBLab Forge brief, PostgresAI) https://console.postgres.ai/shared/brief/9fffe2da-00c1-470b-a79d-a210ae2306bcHacking sessions[00:00:51] Hacking Postgres 101: ULID function (Postgres.TV, 2023) https://www.youtube.com/watch?v=YPq_hiOE-N8[00:00:51] Hacking Postgres sessions with Andrey, Kirk and Nik (YouTube playlist, PostgresTV) https://www.youtube.com/playlist?list=PLH8y1BNPAKjKDdJA7sDmFWUkbbYux3TRzEpisodes[00:05:53] Our previous episode with Kirk, also built on DBLab Forge: Dump/restore done. Now what? https://postgres.fm/episodes/dump-restore-done-now-whatPostgres[00:01:34] Commit adding uuidv7() to Postgres 18 (78c5e141e9c1, 2024-12-11) https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=78c5e141e9c1[00:04:16] UUID functions, uuidv7() and uuid_extract_timestamp() (docs) https://www.postgresql.org/docs/18/functions-uuid.html[00:20:42] full_page_writes (docs) https://www.postgresql.org/docs/current/runtime-config-wal.html#GUC-FULL-PAGE-WRITES[00:25:01] wal_compression, lz4 and zstd (docs) https://www.postgresql.org/docs/current/runtime-config-wal.html#GUC-WAL-COMPRESSION[00:31:07] pg_stat_io (docs) https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-IO-VIEWStandards and ID schemes[00:01:20] RFC 9562, Universally Unique IDentifiers (UUIDv7) https://www.rfc-editor.org/rfc/rfc9562[00:28:05] ULID spec https://github.com/ulid/spec[00:41:29] Snowflake ID (Twitter) https://github.com/twitter-archive/snowflake[00:41:29] Sharding & IDs at Instagram https://instagram-engineering.com/sharding-ids-at-instagram-1cf5a71e5a5cArticles, books and tools[00:05:34] Sequential UUID generators (Tomas Vondra, 2018) https://www.enterprisedb.com/blog/sequential-uuid-generators[00:05:59] Systems Performance, 2nd edition (Brendan Gregg) https://www.brendangregg.com/systems-performance-2nd-edition-book.html[00:12:25] fio https://github.com/axboe/fio[00:26:17] Amazon Aurora pricing (I/O charges) https://aws.amazon.com/rds/aurora/pricing/[00:32:53] UUIDv7 doesn't have the properties you think it does (Robert Alexander, 2026) https://alexsci.com/blog/uuidv7-is-weird/[00:32:53] Hacker News discussion of that article https://news.ycombinator.com/item?id=50211746~~~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 PostgresAIWith credit to:Jessie Draws for the elephant artworkIntro and outro music: our own arrangement of Apple Loops from GarageBand (royalty-free under the GarageBand licence)

Nik is joined by Kirk Wolak, Software Architect at KiraSoft, to discuss what a database still needs after pg_restore finishes and before it takes production traffic — what pg_dump and pg_restore leave behind, why autovacuum may not catch up in time, and how Postgres itself could do better. Here are some links to things they mentioned: Times are podcast times of the first mention.Hacking sessions[00:00:27] Hacking Postgres sessions with Andrey, Kirk and Nik (YouTube playlist, PostgresTV) https://www.youtube.com/playlist?list=PLH8y1BNPAKjKDdJA7sDmFWUkbbYux3TRz[00:00:27] Hacking Postgres website https://hacking.postgres.tv[00:00:27] Hacking Postgres Telegram group https://t.me/postgres_hackingEpisodes[00:00:27] Our previous episode with Kirk: GSoC B-Tree Merge https://postgres.fm/episodes/gsoc-btree-merge[00:03:23] Is pg_dump a backup tool? https://postgres.fm/episodes/is-pg_dump-a-backup-toolpgsql-hackers[00:15:39] pg_restore --include-analyze proposal (Jian He, 2025) https://www.postgresql.org/message-id/flat/CACJufxGx_YLLxmnZVMuUApiVYqjKrydvEQqD3qxhwM6e0_8jrQ%40mail.gmail.com[00:30:13] ANALYZE after restore (Christopher Kings-Lynne, 2002) https://www.postgresql.org/message-id/GNELIHDDFBOCMGBFGEFOOEOPCBAA.chriskl%40familyhealth.com.au[00:31:55] Statistics Import and Export (PG18 statistics transfer) https://www.postgresql.org/message-id/flat/CADkLM%3DfzX7QX6r78fShWDjNN3Vcr4PVAnvXxQ4DiGy6V%3D0bCUA%40mail.gmail.comCommits[00:04:39] Transfer statistics during pg_upgrade (adds statistics to pg_dump, PG18) https://github.com/postgres/postgres/commit/1fd1bd871012732e3c6c482667d2f2c56f1a9395[00:30:13] vacuumdb --analyze-only processes partitioned tables (Laurenz Albe, PG19) https://github.com/postgres/postgres/commit/6429e5b771dbb98aa56441677b79cdb58f6e1675[00:42:38] Set pd_prune_xid on insert (Melanie Plageman, PG19) https://github.com/postgres/postgres/commit/378a216187aea1b488ce60ed07dd1ac5c14a9984~~~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 PostgresAIWith credit to:Jessie Draws for the elephant artworkIntro and outro music: our own arrangement of Apple Loops from GarageBand (royalty-free under the GarageBand licence)

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. Here are some links to things they mentioned: Álvaro Hernández https://postgres.fm/people/alvaro-hernandez-tortosaOngres https://ongres.comScaling Citus without limits: announcing Query Routers in StackGres https://stackgres.io/blog/scaling-citus-beyond-one-coordinator-announcing-query-routers-stackgres/Open-source Citus matches PlanetScale's Neki at 10M QPS on half the data nodes https://stackgres.io/blog/open-source-citus-matches-planetscales-neki-at-10m-qps-on-half-the-data-nodes/Postgres TV discussion about licenses with Álvaro https://www.youtube.com/watch?v=1rcbyIjA4gIOur episode with Sugu from Multigres https://postgres.fm/episodes/multigresOur (first) episode with Lev from PgDog https://postgres.fm/episodes/pgdogCitus https://github.com/citusdata/citusCitus goes fully open source (2022) https://www.citusdata.com/blog/2022/06/17/citus-11-goes-fully-open-source/6M requests per second using ClickHouse (blog post by Alex Bocharov / Cloudflare) https://blog.cloudflare.com/http-analytics-for-6m-requests-per-second-using-clickhouse/pg_ash https://github.com/NikolayS/pg_ash118 million queries per second on Neki (blog post by Florent Poinsard and Hirad Pourtahmasbi / PlanetScale) https://planetscale.com/blog/118-million-queries-per-second-on-nekiAnalyzing the Limits of Connection Scalability in Postgres (blog post by Andres Freund) https://www.citusdata.com/blog/2020/10/08/analyzing-connection-scalability/~~~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

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. Here are some links to things they mentioned:  Salma El-Sayed https://postgres.fm/people/salma-el-sayedKirk Wolak https://postgres.fm/people/kirk-wolakGoogle Summer of Code https://summerofcode.withgoogle.comPostgreSQL GSoC 2026 project ideas https://wiki.postgresql.org/wiki/GSoC_2026CMU Intro to Database Systems https://www.youtube.com/playlist?list=PLSE8ODhjZXjYMAgsGH-GtY5rJYZ6zjsd5Kirk, NIK, and Andrey’s Hacking Postgres sessions on YouTube https://www.youtube.com/playlist?list=PLH8y1BNPAKjKDdJA7sDmFWUkbbYux3TRzB-tree Index Bloat Reduction - Approach & Questions (Hackers thread, with patches) https://www.postgresql.org/message-id/flat/CANBEAPFq3YAOydjUS3xwcUG9L6e3WE5Z4nGPk_Q3RsjSFWTJNA%40mail.gmail.comB-tree merge visualizer https://kirkw.github.io/explainers/btree-merge-explainer.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 credit to:Jessie Draws for the elephant artwork

Nik and Michael are joined by Sai Srirampur to discuss ClickHouse's new managed Postgres service. Here are some links to things they mentioned: Sai Srirampur https://postgres.fm/people/sai-srirampurClickHouse Managed Postgres https://clickhouse.com/cloud/postgresClickPipes https://clickhouse.com/cloud/clickpipeswalshadow https://github.com/ClickHouse/walshadowpg_clickhouse https://github.com/clickHouse/pg_clickhouseClickHouse PostgreSQL powered by Ubicloud https://www.ubicloud.com/blog/clickhouse-postgresql-powered-by-ubicloudHacking Postgres logical decoding sessions https://hacking.postgres.tv/topics/logical-decoding/ wal-rus https://github.com/ClickHouse/wal-ruspg_createsubscriber https://www.postgresql.org/docs/current/app-pgcreatesubscriber.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 credit to:Jessie Draws for the elephant artwork

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. Here are some links to things they mentioned: hot_standby_feedback https://www.postgresql.org/docs/current/runtime-config-replication.html#GUC-HOT-STANDBY-FEEDBACKhot_standby_feedback: experiments on PostgreSQL 17 (by Nik) https://console.postgres.ai/shared/brief/6018f69d-8975-48e3-8259-a72c77105572Best practices for Amazon RDS PostgreSQL replication (blog post) https://aws.amazon.com/blogs/database/best-practices-for-amazon-rds-postgresql-replication/log_autovacuum_min_duration https://www.postgresql.org/docs/current/runtime-config-logging.html#GUC-LOG-AUTOVACUUM-MIN-DURATIONmax_standby_streaming_delay https://www.postgresql.org/docs/current/runtime-config-replication.html#GUC-MAX-STANDBY-STREAMING-DELAYWAIT FOR LSN https://www.postgresql.org/docs/19/sql-wait-for.htmltransaction_timeout https://www.postgresql.org/docs/current/runtime-config-client.html#GUC-TRANSACTION-TIMEOUTHot Standby Feedback should default to on in 9.3+ https://www.postgresql.org/message-id/flat/20121130190227.GJ3957%40awork2.anarazel.de~~~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

Nik and Michael are joined by Shaun Thomas to discuss estimating work_mem, memory management in general, and writing an extension to help. Here are some links to things they mentioned: Shaun Thomas https://postgres.fm/people/shaun-thomaswork_mem https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-WORK-MEMpg_stat_database https://www.postgresql.org/docs/current/monitoring-stats.html#MONITORING-PG-STAT-DATABASE-VIEWALTER ROLE SET configuration_parameter https://www.postgresql.org/docs/current/sql-alterrole.html#SQL-ALTERROLE-PARAMS-CONFIGURATION-PARAMETERhash_mem_multiplier https://www.postgresql.org/docs/current/runtime-config-resource.html#GUC-HASH-MEM-MULTIPLIERRecent Postgres releases with 28 CVEs fixed https://www.postgresql.org/about/news/postgresql-186-1711-1615-1519-1424-and-19-beta-3-released-3365/Systemic Risks in the Managed PostgreSQL Industry (part 1 of 6, Mehmet Ince) https://mehmetince.net/part-1-6-systemic-risks-in-the-managed-postgresql-industry-extension-risks-are-real-exploiting-postgis-memory-corruption-bug-at-neondb-supabase-and-many-more/Improving Postgres Connection Scalability: Snapshots (blog post by Andres Freund) https://techcommunity.microsoft.com/blog/adforpostgresql/improving-postgres-connection-scalability-snapshots/1806462~~~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

Nik and Michael are joined by Michael Malis, co-creator of pgrust, to discuss their Postgres rewrite, including reliability problems, compatibility testing, faster analytics, and a new JIT-compiled query engine. Here are some links to things they mentioned: Michael Malis https://postgres.fm/people/michael-malispgrust https://github.com/malisper/pgrust The four horsemen behind Postgres outages (blog post by Michael Malis) https://malisper.me/the-four-horsemen-behind-thousands-of-postgres-outagesRebuilding Postgres for faster analytics: batching, operator fusion, and SIMD (blog post by Michael Malis) https://malisper.me/how-we-made-postgres-hundreds-of-times-faster-the-query-engine/kani https://github.com/model-checking/kaniAntithesis https://antithesis.comfsyncgate mailing list thread https://www.postgresql.org/message-id/flat/CAMsr%2BYHh%2B5Oq4xziwwoEfhoTZgr07vdGG%2Bhu%3D1adXx59aTeaoQ%40mail.gmail.comHow AI Changes the Economics of JIT Compilers (blog post by Michael Malis) https://malisper.me/how-ai-changes-the-economics-of-jit-compilers/Umbra DB https://umbra-db.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 credit to:Jessie Draws for the elephant artwork

Nik and Michael are joined by Radim Marek to discuss MVCC, including his recent article on how Postgres chose to implement it compared to other systems. Here are some links to things they mentioned: Radim Marek https://postgres.fm/people/radim-marekBoringSQL https://boringsql.comPostgreSQL's MVCC is bad. So is everyone else's (blog post by Radim) https://boringsql.com/posts/mvcc-bad-bad/PostgreSQL MVCC documentation https://www.postgresql.org/docs/current/mvcc-intro.htmlPostgreSQL Storage Internals series by Radim https://boringsql.com/guides/postgresql-storage-internals/PgQue https://github.com/NikolayS/pgqueThe next ten years of Postgres (talk slides by Álvaro Herrera) https://www.postgresql.eu/events/pgconfde2026/sessions/session/7744/slides/866/edb-keynote-pgconfde-2026.pdfEpisode on RegreSQL https://postgres.fm/episodes/regresqlDryRun MCP https://github.com/boringsql/dryrun~~~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