Why it's fun to hack on Postgres performance with Tomas Vondra | Talking Postgres Ep36

Why would anyone willingly spend weeks chasing a slow query, knowing they might hit dead ends along the way? In Episode 36 of Talking Postgres, Tomas Vondra—Postgres committer and long‑time performance contributor—joins Claire to explain why hacking on Postgres performance is not just hard, but also fun. We dig into the process of investigating why queries are slow, how iteration and “wrong turns” are part of performance work, and why Tomas prefers meaningful performance puzzles over toy problems. Along the way, we talk about using benchmarks to build an understanding of a problem. Tomas also shares how even small changes in code can have outsized impact when that code is used a lot, and how the mathematics embedded in the Postgres query planner/executor makes the work especially rewarding.

Chapters:
⏩ 00:00 Music & introduction
⏩ 02:30 PHP performance bug led me to Postgres
⏩ 09:50 Analytical mind vs synthesis
⏩ 12:22 Performance issues are like puzzles
⏩ 15:59 Optimizing hash joins
⏩ 31:21 Office hours for Postgres contributors
⏩ 43:57 Monthly PostgreSQL Hacking workshop
⏩ 51:09 Hobby of reading research papers
⏩ 52:47 That feeling of achievement
⏩ 53:24 Index prefetching: a three-year journey
⏩ 59:16 Learning by benchmarking
⏩ 1:05:52 Learning via patch review

📜 Full transcript available at:
https://talkingpostgres.com/episodes/why-its-fun-to-hack-on-postgres-performance-with-tomas-vondra/transcript

✅ Listen to more episodes of Talking Postgres:
https://talkingpostgres.com

💥 Subscribe to Talking Postgres, so you never miss an episode:
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Previously on Talking Postgres:

🔹 Talking Postgres podcast Ep31 with Andres Freund: https://youtu.be/bVei7-AyMJ8?si=pWGmk_AR9zux5YRu
🔹 Talking Postgres podcast Ep24 with Robert Haas: https://youtu.be/4wSDnx8di6o?si=iELyZym9iFzdPAfG

More Links mentioned in this episode:

🔹 PGConf.dev schedule for May 19-22, 2026: https://2026.pgconf.dev/schedule/wednesday
🔹 PostgreSQL Monthly Hacking Workshop, organized by Robert Haas: https://github.com/pghacking/workshop
🔹 Nordic PGDay 2026 talk on approximating percentiles: https://www.postgresql.eu/events/nordicpgday2026/schedule/session/7466-efficiently-approximatingestimating-percentiles-and-histograms/
🔹 Video of POSETTE 2025 talk on Performance Archaeology – 20 years of improvements: https://youtu.be/IY7Nl2sY9fQ?si=gASlmb3BLbXEolrG
🔹 Video of PGConf EU 2025 talk on Fast-path locking improvements in PG18: https://youtu.be/ZPrRJuCTg6A?si=BK9FnwPQ6YuTAg65
🔹 Prague PostgreSQL Developer Day: https://p2d2.cz/en/
🔹 PostgreSQL Hacking Discord: https://discord.gg/bx2G9KWyrY
🔹 GitHub repo for tdigest: https://github.com/tvondra/tdigest
🔹 Brendan Gregg’s site with perf Linux profiler examples: https://www.brendangregg.com/perf.html
🔹 pgbench for running benchmarks on PostgreSQL: https://www.postgresql.org/docs/current/pgbench.html
🔹 Tomas Vondra blog: https://vondra.me/
🔹 Tomas Vondra list of Postgres Patch Ideas: https://vondra.me/tags/patch-idea/
🔹 Calendar invite: LIVE recording of Ep37 of Talking Postgres to happen on Wed Mar 18, 2026: https://aka.ms/TalkingPostgres-Ep37-cal

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