Postgres FM

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-a210ae2306bc

Hacking 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=PLH8y1BNPAKjKDdJA7sDmFWUkbbYux3TRz

Episodes
[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-what

Postgres
[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-VIEW

Standards 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-1cf5a71e5a5c

Articles, 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

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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!

~~~
Postgres FM is produced by:
Michael Christofides, founder of pgMustard
Nikolay Samokhvalov, founder of PostgresAI

With credit to:
Jessie Draws for the elephant artwork
Intro 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_hacking

Episodes
[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-tool

pgsql-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.com

Commits
[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 pgMustard
Nikolay Samokhvalov, founder of PostgresAI

With credit to:
Jessie Draws for the elephant artwork
Intro 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-tortosa
Ongres https://ongres.com
Scaling 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=1rcbyIjA4gI
Our episode with Sugu from Multigres https://postgres.fm/episodes/multigres
Our (first) episode with Lev from PgDog https://postgres.fm/episodes/pgdog
Citus https://github.com/citusdata/citus
Citus 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_ash
118 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-neki
Analyzing 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 pgMustard
Nikolay Samokhvalov, founder of Postgres.ai

With 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-sayed
Kirk Wolak https://postgres.fm/people/kirk-wolak
Google Summer of Code https://summerofcode.withgoogle.com
PostgreSQL GSoC 2026 project ideas https://wiki.postgresql.org/wiki/GSoC_2026
CMU Intro to Database Systems https://www.youtube.com/playlist?list=PLSE8ODhjZXjYMAgsGH-GtY5rJYZ6zjsd5
Kirk, NIK, and Andrey’s Hacking Postgres sessions on YouTube https://www.youtube.com/playlist?list=PLH8y1BNPAKjKDdJA7sDmFWUkbbYux3TRz
B-tree Index Bloat Reduction - Approach & Questions (Hackers thread, with patches) https://www.postgresql.org/message-id/flat/CANBEAPFq3YAOydjUS3xwcUG9L6e3WE5Z4nGPk_Q3RsjSFWTJNA%40mail.gmail.com
B-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 pgMustard
Nikolay Samokhvalov, founder of Postgres.ai

With 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-srirampur
ClickHouse Managed Postgres https://clickhouse.com/cloud/postgres
ClickPipes https://clickhouse.com/cloud/clickpipes
walshadow https://github.com/ClickHouse/walshadow
pg_clickhouse https://github.com/clickHouse/pg_clickhouse
ClickHouse PostgreSQL powered by Ubicloud https://www.ubicloud.com/blog/clickhouse-postgresql-powered-by-ubicloud
Hacking Postgres logical decoding sessions https://hacking.postgres.tv/topics/logical-decoding/ 
wal-rus https://github.com/ClickHouse/wal-rus
pg_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 pgMustard
Nikolay Samokhvalov, founder of Postgres.ai

With credit to:
Jessie Draws for the elephant artwork