Postgres FM

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.com/watch?v=gAgbzvGT6ck pgstattuple https://www...

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/pgvector/pgvector Our episode on companion databases...

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 things they mentioned: pgBadger website https://p...

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-explain.html EXPLAIN Explained (talk by Josh Berkus ht...

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 .

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 Andrey and Kirk: https://www.youtube.com/watch...

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 (docs) https://www.postgresql.org/docs/current/...

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.org/message-id/flat/CANNMO%2B%2B7%2BuVMj%2BZPG...

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-phriday-014-postgresql-events/   PGCon https://www.pg...

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 Harmful (blog post by Nikolay) https://post...

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-state-machines-incident-response-and-data-soup-a...

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 PostgreSQL and Amazon RDS for PostgreSQL https://...

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://en.wikipedia.org/wiki/Boyce–Codd_normal_fo...

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 https://www.pgmustard.com/docs/explain/sequential...

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) optimization https://www.postgresql.org/docs/current/...

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) https://www.postgresql.org/docs/current/planner-...

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 restart attempts https://twitter.com/samokhval...

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/current/app-pgbasebackup.html pgBackRest https:...

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 Hewlett Packard Enterprise Japan) https://h50146.ww...

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-loaded clusters with zero-downtime https://twit...

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 podcast https://postgres.fm/subscribe A recen...

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-LISTEN-ADDRESSES   SSLMODE Explained (blog po...

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.com/rds/aurora/ Google Cloud AlloyDB for PostgreSQL...

Nikolay and Michael discuss self-managing Postgres — both the practicalities of doing so, as well as some managed-service style tooling.    Here are some links to some things they mentioned: Our episode on Managed services vs. DIY https://postgres.fm/episodes/managed-services-vs-diy   WAL-G https://github.com/wal-g/wal-g   pgBackRest https://pgbackrest.org/   Barman https://github.com/EnterpriseDB...

Nikolay and Michael discuss sharding Postgres — what it means, why and when it's needed, and the available options right now.    Here are some links to some things they mentioned: PGSQL Friday monthly blogging event https://www.pgsqlphriday.com/ Did “sharding” come from Ultima Online? https://news.ycombinator.com/item?id=23438399   Our episode on partitioning: https://postgres.fm/episodes/partitio...