Nikolay and Michael discuss Index-Only Scans in Postgres — what they are, how they help, some things to look out for, and some advice. Here are some links to things they mentioned: Index-Only Scans and Covering Indexes (docs) https://www.postgresql.org/docs/current/indexes-index-only-scans.html Discussion on Twitter about JIT and Parallel Query def…

Nikolay and Michael discuss why they chose Postgres — as users, for their businesses, for their careers, as well as some doubts. Here are some links to things they mentioned: Our episode on why Postgres become popular https://postgres.fm/episodes/why-is-postgres-popular Database Systems: The Complete Book (by Hector Garcia-Molina, Jeff Ullman, and …

By Nikolay Samokhvalov and Michael Christofides

Nikolay and Michael discuss Postgres running out of disk space — including what happens, what can cause it, how to recover, and most importantly, how to prevent it from happening in the first place. Here are some links to things they mentioned: Disk Full (docs) https://www.postgresql.org/docs/current/disk-full.html pgcompacttable https://github.com…

Nikolay and Michael discuss the Postgres startup ecosystem — some recent closures, some recent fundraising announcements, and their thoughts on where things are going and what they'd like to see. Here are some links to things they mentioned: Prediction from Dax Raad https://x.com/thdxr/status/1808972166752580039 OtterTune shut down https://x.com/an…

Nikolay talks Michael through a recent experiment to find the current maximum transactions per second single-node Postgres can achieve — why he was looking into it, what bottlenecks occurred along the way, and ideas for follow up experiments. Here are some links to things they mentioned: How many TPS can we get from a single Postgres node? (Article…

Nikolay and Michael discuss soft deletion in Postgres — what it means, several use cases, some implementation options, and which implementations suit which use cases. Here are some links to things they mentioned: Soft deletion probably isn't worth it (blog post by Brandur) https://brandur.org/soft-deletion Easy alternative soft deletion (blog post …

Nikolay and Michael discuss foreign keys in Postgres — what they are, their benefits, their overhead, some edge cases to be aware of, some improvements coming, and whether or not they generally recommend using them. Here are some links to things they mentioned: Foreign keys (docs) https://www.postgresql.org/docs/current/ddl-constraints.html#DDL-CON…

Nikolay is joined by Mat Arye and John Pruitt, from Timescale, to discuss their new extension pgvectorscale and high-performance vector search in Postgres more generally. Main links: https://github.com/timescale/pgvectorscale https://www.timescale.com/blog/pgvector-vs-pinecone https://postgres.fm/people/matvey-arye https://postgres.fm/people/john-p…

Michael and Nikolay are joined by three special guests for episode 100 who have all scaled Postgres to significant scale — Arka Ganguli from Notion, Sammy Steele from Figma, and Derk van Veen from Adyen. They cover how their setup has evolved, what their plans are for the future, and get into the weeds of some fun and interesting challenges along t…

Michael is joined by Claire Giordano, Head of Postgres Open Source Community Initiatives at Microsoft, to discuss several ways to contribute to the Postgres community — from core contributions, to extensions, to events, and (of course) podcasts. Here are some links to things they mentioned: What’s new with Postgres at Microsoft (blog post by Claire…

Nikolay and Michael discuss full text search in Postgres — some of the history, some of the features, and whether it now makes sense to try to replace or combine it with semantic search. Here are some links to things they mentioned: Full Text Search https://www.postgresql.org/docs/current/textsearch.html tsearch2 https://www.postgresql.org/docs/9.6…

Nikolay and Michael discuss Postgres minor releases — how the schedule works, options for upgrading to them, and the importance of reading the release notes. Here are some links to things they mentioned: PostgreSQL 16.3, 15.7, 14.12, 13.15, and 12.19 released (announcement) https://www.postgresql.org/about/news/postgresql-163-157-1412-1315-and-1219…

Nikolay and Michael discuss custom and generic planning in prepared statements — how it works, how issues can present themselves, some ways to view the generic plan, and some benefits of avoiding planning (not just time). Here are some links to things they mentioned: PREPARE https://www.postgresql.org/docs/current/sql-prepare.html track_activity_qu…

Nikolay and Michael discuss LIMIT in Postgres — what it does, how it can help with performance, and an interesting example where adding it can actually hurt performance(!) Here are some links to things they mentioned: LIMIT considered harmful in PostgreSQL (Twitter thread by Christophe Pettus) https://twitter.com/Xof/status/1413542818673577987 LIMI…

Nikolay and Michael return to the topic of using the buffers explain parameter — with a new analogy, some (conspiracy) theories of why it's still not on by default, and some related chat about the serialize parameter coming in 17. Here are some links to things they mentioned: BUFFERS by default (episode 4) https://postgres.fm/episodes/buffers-by-de…

Nikolay and Michael discuss doing massive DELETE operations in Postgres — what can go wrong, how to prevent major issues, and some ideas to minimise their impact. Here are some links to things they mentioned: Article based on Nikolay’s talk, including batching implementation (translated to English) https://habr-com.translate.goog/en/articles/523536…

Nikolay and Michael are joined by Sai Srirampur, CEO and Co-founder of PeerDB, to discuss how to overcome several logical replication issues. They discuss the protocol versions, minimising slot growth, minimising lag, and some tips and tricks for scaling things well. Here are some links to things they mentioned: PeerDB https://www.peerdb.io/ Our ep…

Nikolay and Michael discuss several "Don't do this" lists about Postgres — picking out their favourite items, as well as some contentious ones that could be clearer, or not included. Here are some links to things they mentioned: Don’t do this (PostgreSQL wiki page) https://wiki.postgresql.org/wiki/Don't_Do_This How to get into trouble using some Po…

Nikolay and Michael have a high-level discussion on all things search — touching on full-text search, semantic search, and faceted search. They discuss what comes in Postgres core, what is possible via extensions, and some thoughts on performance vs implementation complexity vs user experience. Here are some links to things they mentioned: Simon Ri…

Nikolay and Michael discuss Postgres health checks — what they are, things to include, how often makes sense, and whether improvements to Postgres would increase or decrease the need for them. Here are some links to things they mentioned: MOT (car test in the UK) https://en.wikipedia.org/wiki/MOT_test Let's make PostgreSQL multi-threaded (discussio…

Nikolay and Michael discuss the superuser role in PostgreSQL — what it is, how and when it shouldn’t be used, and whether most cloud providers are right to not give us it (no prizes for guessing). Here are some links to things they mentioned: superuser (docs) https://www.postgresql.org/docs/current/role-attributes.html#id-1.6.9.6.2.1.2.1.1 Crunchy …

Nikolay and Michael discuss transaction_timeout (a recently committed addition for Postgres 17) — what it's for, how to get around not having it already, and whether it will replace the need to set statement_timeout globally in future. Here are some links to things they mentioned: transaction_timeout (devel docs) https://www.postgresql.org/docs/dev…

Michael and Nikolay are joined by Andrew Atkinson, author of High Performance PostgreSQL for Rails, to discuss how Rails and Postgres work together — where the limits are, how people use the ORM, things that are improving, and some things we can do as a Postgres community to make it even better. Here are some links to things they mentioned: Planet …

Nikolay and Michael discuss a common question — why Postgres isn't using an index, and what you can do about it! Here are some links to things they mentioned: Why isn’t Postgres using my index? (blog post by Michael) https://www.pgmustard.com/blog/why-isnt-postgres-using-my-index Why isn’t Postgres using my functional index? (Stack Exchange questio…

Nikolay and Michael discuss the overhead of pg_stat_statements and pg_stat_kcache — mostly focusing on some interesting things Nikolay found while stress-testing some large spot instances up to and beyond 2m TPS(!) Here are some links to things they mentioned: pg_stat_statements https://www.postgresql.org/docs/current/pgstatstatements.html pg_stat_…

Michael is joined by Markus Winand, creator of use-the-index-luke.com and modern-sql.com, and author of SQL Performance Explained, to discuss Modern SQL — what Markus means by it, why it's important, some benefits, some examples, and at least one phrase that should be on a t-shirt. Here are some links to things they mentioned: Modern SQL (site) htt…

Michael is joined by Chelsea Dole, Staff Software Engineer and Tech Lead of the Data Storage Team at Brex, to discuss bloat. They cover what it is, why it's a problem, strategies for minimising it, and the options when it's really bad. Here are some links to things they mentioned: Managing your tuple graveyard (talk by Chelsea) https://www.youtube.…

Michael is joined by Jonathan Katz, PostgreSQL Core Team member, Principle Product Manager at AWS, and also pgvector contributor, to discuss pgvector. They cover what it is, why it's so popular all of a sudden, some tuning and tradeoff guidance, and a look to the future. Here are some links to things they mentioned: pgvector https://github.com/pgve…

Michael is joined by Alicja Kucharczyk, Program Manager for Azure Database for PostgreSQL at Microsoft and organiser of the Warsaw PostgreSQL User Group, to discuss Alicja's favorite tool: pgBadger. They cover what it is, how and when it's useful, and some guidance for getting the most out of it (without causing an outage). Here are some links to t…

With Nikolay taking a well-earned break, Michael covers the basics of EXPLAIN — what it is, the parameters available, and a process he recommends for using it. Here are some links to the things mentioned: EXPLAIN (docs) https://www.postgresql.org/docs/current/sql-explain.html Using EXPLAIN (docs) https://www.postgresql.org/docs/current/using-explai…

Happy holidays! Today's topic is work_mem — how it's used and how to tune it. Related post: https://x.com/samokhvalov/status/1740813478150189172?s=46&t=HSxrW86NZqzPQP9vXVJEWg.By Nikolay Samokhvalov and Michael Christofides

Nikolay and Michael discuss partitioning by ULID — revisiting some of the old UUID vs bigint key debate in light of some new UUID specs, and how these can be used for partitioning (by time). Here are some links to things they mentioned: Nikolay’s episode on UUID (for primary keys) https://postgres.fm/episodes/uuid Postgres TV hacking session with A…

Nikolay and Michael discuss hash indexes in Postgres — what they are, some brief history, their pros and cons vs btrees, and whether or when they recommend using them. Update: the idea Nikolay mentioned at the end of this episode turns out to be a little fraught (and as such, inadvisable). Here are some links to things they mentioned: Index types (…

Nikolay and Michael discuss PostgreSQL constraints — the six different types we have, how to add and modify them, including on large tables with high TPS. Here are some links to things they mentioned: Constraints (docs) https://www.postgresql.org/docs/current/ddl-constraints.html Unique index vs unique constraint issue (2017) https://www.postgresql…

Nikolay and Michael discuss PostgreSQL events — whether in-person or online, large conferences or small meet-ups, as well as some strong opinions based on their experiences attending, speaking, and organising them. Here are some links to things they mentioned: PGSQL Phriday #014: PostgreSQL Events https://www.cybertec-postgresql.com/en/pgsql-phrida…

Nikolay and Michael discuss PostgreSQL subtransactions — what they are, and four issues they can cause at scale. Here are some links to things they mentioned: Subtransactions (docs) https://www.postgresql.org/docs/current/subxacts.html SAVEPOINT (docs) https://www.postgresql.org/docs/current/sql-savepoint.html PostgreSQL Subtransactions Considered …

Nikolay and Michael discuss companion databases — when and why you might want to add another database management system to your stack (or not), and some specifics for analytics, timeseries, search, and vectors. Here are some links to things they mentioned: Heap were using Postgres + Citus for analytics as of 2022 https://www.heap.io/blog/juggling-s…

Nikolay and Michael discuss blue-green deployments — specifically an RDS blog post, how similar this is (or not) to what they understand to be blue-green deployments, and how applicable the methodology might be in the database world more generally. Here are some links to things they mentioned: Fully managed Blue/Green Deployment in Amazon Aurora Po…

Nikolay and Michael discuss data model trade-offs — some cases where you might want to (gasp) de-normalize, and which PostgreSQL internals are at play. Here are some links to things they mentioned: Our episode on JSON https://postgres.fm/episodes/json PostgreSQL limits https://www.postgresql.org/docs/current/limits.html Boyce–Codd normal form https…

Nikolay and Michael discuss under-indexing — how to tell if this applies to you, some general and specific cases, as well as some tricky ones. Here are some links to things they mentioned: Indexes (docs) https://www.postgresql.org/docs/current/indexes.html random_page_cost https://postgresqlco.nf/doc/en/param/random_page_cost/ Sequential scans http…

Nikolay and Michael discuss over-indexing — what we mean by it, the regular issues people discuss about it, as well as a novel one Nikolay has come across and benchmarked recently. Here are some links to things they mentioned: Nikolay’s tweet on over-indexing https://twitter.com/samokhvalov/status/1713101666629927112 Heap-Only Tuples (HOT) optimiza…

Nikolay and Michael discuss query hints — what they are, what we do and don't have in PostgreSQL, and some other things in and around the ecosystem to be aware of. Here are some links to some extra things they mentioned: Query planning (docs) https://www.postgresql.org/docs/current/runtime-config-query.html Statistics used by the planner (docs) htt…

In this episode (recorded live on YouTube), Nikolay discusses Postgres shutdown and startup times – how to troubleshoot them and, when needed, optimize. Some extra things mentioned in this episode: #PostgresMarathon series – every day, Nikolay posts a new howto-style article https://twitter.com/hashtag/PostgresMarathon Day 2: Postgres shutdown and …

Nikolay and Michael discuss Postgres backups — why we need them, what the options are, whether a dump is a backup or not, and some considerations for lowering RPO and RTO at scale. Here are some links to some extra things they mentioned: pg_dump https://www.postgresql.org/docs/current/app-pgdump.html pg_basebackup https://www.postgresql.org/docs/cu…

Nikolay and Michael discuss the release of PostgreSQL 16 — the most important new features, what they mean for us as users, whether and when to upgrade, and more. Here are some links to some extra things they mentioned: Release notes https://www.postgresql.org/docs/current/release-16.html New Features With Examples (PDF from Noriyoshi Shinoda of He…

Nikolay and Michael discuss logical replication — some history, initialization, change data capture, how to scale it, some limitiations, and ways that it is getting better. Here are some links to some things they mentioned: Logical replication https://www.postgresql.org/docs/current/logical-replication.html GitLab upgraded multi-terabyte, heavily-l…

Nikolay and Michael discuss their favourite feature each from the upcoming PostgreSQL 16 release. Here are some links to some things they mentioned: v16 draft release notes https://www.postgresql.org/docs/16/release-16.html PGSQL Phriday #012 invitation from Ryan Booz https://www.pgsqlphriday.com/2023/08/pgsql-phriday-012/ Subscribe options for the…

Nikolay and Michael discuss connections — the options, security and performance tradeoffs, and a few other things to be aware of. Here are some links to some things they mentioned: Episode on connection poolers https://postgres.fm/episodes/connection-poolers listen_addresses https://www.postgresql.org/docs/current/runtime-config-connection.html#GUC…

Nikolay and Michael discuss a listener question — about products that take Postgres and transform it to something that decouples compute from storage (RDS Aurora, GC AlloyDB, Neon etc.) and whether they see something like this landing upstream in the medium term. Here are some links to some things they mentioned: Amazon Aurora https://aws.amazon.co…