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Michael Christofides

@michristofides.com
117 followers 181 following 42 posts

Half of the team behind @pgmustard.com and (a different) half of the team behind Postgres FM

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Michael Christofides @michristofides.com · 8h
I missed the mastodon migration horror story, son't suppose you have a link?
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pgMustard @pgmustard.com · 22/07/2026
The upcoming Postgres 19 is set to include extra EXPLAIN info in several places: 🚦 An "IO" parameter (async info) 💡 Generated and supplied hint info (pg_plan_advice) ♻️ Memoize estimate fields 🪵 WAL full page image bytes We've added support for them all in @pgmustard.com 🎉
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Michael Christofides @michristofides.com · 30/04/2026
Unfortunately the cost model for determining when it’s beneficial is difficult to make accurate, and for OLTP workloads the risk of massively slowing down a fast query is problematic. Latest discussion on the mailing list: www.postgresql.org/message-id/f...
postgresql.org
Change default of jit to off
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Michael Christofides @michristofides.com · 30/04/2026
Nice to see that JIT will now be off by default from Postgres 19: git.postgresql.org/gitweb/?p=po...
git.postgresql.org
git.postgresql.org Git - postgresql.git/commitdiff
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Michael Christofides @michristofides.com · 17/03/2026
Hey! Have you looked into getting Hibernate to add comments to the SQL? That’s how some other ORMs do it and it works nicely. We even discussed it on a recent podcast episode postgres.fm/episodes/com...
postgres.fm
Postgres FM | Comments and metadata
Nik and Michael discuss query level comments, object level comments, and another way of adding object level metadata. Here are some links to things they mentioned: Object comments https://www.postg...
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pgMustard @pgmustard.com · 19/02/2026
pgMustard Pro now includes 1,000 API credits 🎉 Bulk-analyse plans, plug into your LLM workflows, or build something we haven't thought of yet. Docs: pgmustard.com/docs#api
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Michael Christofides @michristofides.com · 13/02/2026
¿Por qué no los dos?
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pgMustard @pgmustard.com · 13/02/2026
New blog post: Read efficiency issues in Postgres queries If you've got a query that's slowly degrading in performance, you might have a read efficiency issue. The root cause could be table bloat, index bloat, or data locality degradation. www.pgmustard.com/blog/read-ef...
pgmustard.com
Read efficiency issues in Postgres queries - pgMustard
A lot of the time in database land, our queries are I/O constrained. As such, performance work often involves reducing the number of page reads. Indexes are a prime example, but they don’t solve every...
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Kate McKean @katemckean.bsky.social · 11/02/2026
Over on threads someone just use ai;dr and we all need to adopt that right quick
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pgMustard @pgmustard.com · 20/01/2026
Our Read Efficiency tips are now more efficient to read! 📝 Better wording, mostly for clarity 🔬 More specific to the scan type, and therefore shorter in most cases 🌟 Improved scoring, especially for Bitmap Heap Scans More details: www.pgmustard.com/changelog
A screenshot of two pgMustard windows, with an example query plan in each, and an arrow pointing from the old version to the new. Each has a Bitmap Heap Scan highlighted, and the Read Efficiency tip expanded.
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Michael Christofides @michristofides.com · 06/01/2026
If you have any Postgres performance issues, I'd love to hear about them and try to help: pgmustard.com/office-hours
pgmustard.com
Office hours - pgMustard
For January, I’m offering a private free call (up to 1 hour) to discus anything Postgres performance related.
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Michael Christofides @michristofides.com · 24/12/2025
Have you seen Tomas Vondra’s efforts in this area? m.youtube.com/watch?v=3_Cn...
m.youtube.com
Tomas Vondra - Performance Archaeology (PGConf.EU 2024)
YouTube video by PostgreSQL Europe
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Michael Christofides @michristofides.com · 23/12/2025
Very cool! If you start a label, can I suggest Nusiic Records?
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Michael Christofides @michristofides.com · 12/12/2025
Is that a feature or a bug?
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Michael Christofides @michristofides.com · 04/12/2025
Cool, would be great to hear how it goes! A couple of new options I hadn’t heard of til lately are Apache Cloudberry and pg_lake. It’s cool to see such different implementation efforts, I’m curious to see which of all the options prove popular longer term
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Michael Christofides @michristofides.com · 04/12/2025
Hello! I don't always ask, but I the ones I've seen at that scale have mostly (all?) been sharded... does that count? There's a bunch of Postgres forks/extensions in this space at the moment (I know of them, but haven't tried most). Do you already have a shortlist of options?
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pgMustard @pgmustard.com · 24/11/2025
We've revamped our "Operation on Disk" tips ✨ * Made them clearer * Made them more succinct (in most cases) * Improved the scoring * Mention hash_mem_multiplier (when relevant) * Show "Operation in Memory" in more cases, with the memory used * Updated the linked blog post
A side my side comparison highlighting mostly how much more succinct a new version of the tip can be. The tip wording of the new version is as follows:

This operation wrote out to disk to store temporary data.

Disk space used: 282 MB

Reducing the size of the operation would make it faster, especially if you can get it to fit into working memory.

You can do this by reducing the number of rows, with a LIMIT clause, or reducing the size of each row, by operating on fewer columns.

Another option is to increase the memory available, by adjusting work_mem.

Learn more about working memory (underlined, as it's a link)
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Michael Christofides @michristofides.com · 21/11/2025
I’m a heavy user of Things and a big fan of it! Recurring tasks have nice flexibility, you can choose either “every X”, or “Y after the last one was completed”. Their reminders work well for me, but are only time based (some apps have location based reminders too). Also no shared lists in Things
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incident.io @incident.io · 17/11/2025
Big performance problems 🤝 tiny CS tricks Our latest blog breaks down how bloom filters helped us take an API from 5s to 0.3s - even with millions of alerts in play. If you’re fighting slow queries or Postgres under pressure, this one’s worth a look: go.incident.io/r9jgcI9
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Nik Samokhvalov @samokhvalov.bsky.social · 14/11/2025
Today is the day -- end-of-life for Postgres 13 www.postgresql.org/support/vers...
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Ben @benjdd.com · 04/11/2025
Explain is a powerful tool in Postgres. If you care about performance, get comfortable running `explain` and `explain analyze` commands regularly, and learn how to interpret its output. This blog is a great intro. www.depesz.com/2013/04/16/e...
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JP Camara @jpcamara.com · 12/11/2025
I'm not sure @ankane.bsky.social is human - maybe some kind of open source being from the future 😂 I said to a colleague - "we'll see, but it's ankane, so it's entirely possible it'll get done soon". Less than an hour later, it was updated 🤯
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pgMustard @pgmustard.com · 10/11/2025
New blog post: "What do the new Index Searches lines in EXPLAIN mean?" In Postgres 18 you'll start seeing things like "Index Searches: 1" on each of your index scans. We looked into what they mean, and how that information can be helpful. www.pgmustard.com/blog/what-do...
pgmustard.com
What do the new Index Searches lines in EXPLAIN mean? - pgMustard
In Postgres 18 you’ll now see “Index Searches” lines in EXPLAIN ANALYZE output. If like me you were wondering what those mean exactly, you’re in the right place.
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Andrew Atkinson @andyatkinson.com · 28/09/2025
2 million indexes! You’ve gotta listen to this in context of this Gadget episode with Harry — but that’s a wild figure! 😳 postgres.fm/episodes/gad...
postgres.fm
Postgres FM | Gadget's use of Postgres
Nik and Michael are joined by Harry Brundage from Gadget to talk about their recent zero-downtime major version upgrade, how they use Postgres more generally, their dream database, and some challen...
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Michael Christofides @michristofides.com · 24/09/2025
Hello! I really like pg_stat_statements, then you can look into your queries by all sorts of metrics (eg for read heavy workloads, ordering by total_exec_time is a good starting point). Then I like to run EXPLAIN (ANALYZE, BUFFERS, etc) on the worst offender(s) to look for optimizations
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Benedikt Deicke @benediktdeicke.com · 28/08/2025
Sometimes the trick to optimizing database queries is simple: Don't do stupid stuff.
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Michael Christofides @michristofides.com · 03/09/2025
I'm a bit out of date on the SQL Server side of things, but with Postgres have you already tried turning on track_io_timing and using more of the EXPLAIN parameters? For example: set track_io_timing = on; explain (analyze, buffers, verbose, settings, wal) ...
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pgMustard @pgmustard.com · 20/08/2025
The upcoming Postgres 18 is set to include some nice improvements to EXPLAIN: * BUFFERS on by default with ANALYZE 🎉 * Fractional "actual rows" (huge in some cases) * Quite a few new fields (including the very cool Index Searches) We've now added support for all of them. 💛
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GSM @turnstep.bsky.social · 28/07/2025
Amazing post on making Postgres slower (yes, slower!) on purpose. byteofdev.com/posts/making... #postgres #postgresql Favorite bit: "random_page_cost = 1e300" LOL! Well done
byteofdev.com
Making Postgres 42,000x slower because I am unemployed
As an respectable unemployed person must do, I tried to make Postgres as slow as possible
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Nik Samokhvalov @samokhvalov.bsky.social · 18/07/2025
Really non-trivial case with MultiXacts and brilliant RCA and level of transparency from the Metronome team – great example of what to do with new types of #PostgreSQL incidents! enjoyed discussion a lot! www.youtube.com/watch?v=9KoP...
youtube.com
MultiXact member space exhaustion | Postgres.FM 151 | #PostgreSQL #Postgres podcast
YouTube video by PostgresTV
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Nik Samokhvalov @samokhvalov.bsky.social · 11/07/2025
PostgresFM with Sugu, co-creator of Vitess, originally created to shard MySQL in YouTube, and then used by GitHub, Pinterest, Slack, Shopify, etc. Discussed his work at Supabase on Multigres, sharding for PostgreSQL. Enjoyed a lot!! Take it to a long hike or drive: youtu.be/KOepJivmWTg?...
youtu.be
Multigres | Postgres.FM 150 | #PostgreSQL #Postgres podcast
YouTube video by PostgresTV
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Nik Samokhvalov @samokhvalov.bsky.social · 09/07/2025
3 years of PostgresFM 🥳 And now, @michristofides.com being back from 2-week break, and we've recorded our 150th episode A very interesting one, don't miss -- this Friday
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Elizabeth Garrett Christensen @sqlliz.bsky.social · 08/07/2025
Postgres Meetup for All tomorrow www.meetup.com/postgres-mee...
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Nik Samokhvalov @samokhvalov.bsky.social · 07/07/2025
Amazing talk by Alexander Kukushkin about caveats and myths and truths of sync replication in Postgres. Everyone who works or plans to work with sync replication must watch it! www.youtube.com/watch?v=PFn9...
youtube.com
Myths and Truths about Synchronous Replication in PostgreSQL | POSETTE: An Event for Postgres 2025
YouTube video by Microsoft Developer
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pgMustard @pgmustard.com · 18/06/2025
There are a couple of online #PostgreSQL events today that look like they'll be great: 16:00 UTC — 10 Costly Database Performance Mistakes (and How to Fix Them) with Andy Atkinson www.meetup.com/postgres-mee... 19:00 UTC — 12 years of Postgres Weekly with Peter Cooper aka.ms/TalkingPostg...
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pgMustard @pgmustard.com · 18/06/2025
Hello, Bluesky!
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Michael Christofides @michristofides.com · 12/06/2025
Congrats Jimmy!
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Jimmy Angelakos @vyruss.org · 12/06/2025
I have the great pleasure to announce the release of PostgreSQL Mistakes and How to Avoid Them in all formats! 🎉 To celebrate, @manningbooks.bsky.social is offering a Deal of the Day: 45% off my book and other selected titles! 👉 mng.bz/WrEx #PostgreSQL #Postgres #TechBooks #Database #OpenSource
mng.bz
Deal of the Day
Manning is an independent publisher of computer books, videos, and courses.
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Michael Christofides @michristofides.com · 14/05/2025
Is min short for minimum, or minutes?!!
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Michael Christofides @michristofides.com · 13/05/2025
Well I really like your framing, and other AI techniques like ML seem to mostly have almost the opposite characteristics (can get better than even the most specialised humans, but only at very narrow/highly constrained tasks!)
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Michael Christofides @michristofides.com · 13/05/2025
Very nicely put! It only strengthens your point, but I don’t think chess is even a counter example (other AI techniques sure, just not LLMs)
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Michael Christofides @michristofides.com · 11/05/2025
I actually didn’t, but enjoyed learning it from @raae.dev in the follow up blog post! 🥳
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Michael Christofides @michristofides.com · 07/05/2025
Next week (14th) I'll be joining the excellent Postgres Meetup for All to demo and discuss troubleshooting slow queries using EXPLAIN and external tools: www.meetup.com/postgres-mee... If you or your team could do with an intro or refresher, it would be great to see you there!
meetup.com
Postgres Meetup for All | Meetup
Calling all Postgres enthusiasts! Do you work with Postgres? Do you want to be more involved in the community? Share your learnings? Join our vibrant online community dedicated to PostgreSQL, the worl...
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Brent Ozar @brento.bsky.social · 29/04/2025
I'm proud to announce that I'm teaching a 1-day Postgres performance tuning class at the PASS Summit this year! Registration is open now, and if you register before May 13, you save big with early bird rates. passdatacommunitysummit.com/sessions/1103
passdatacommunitysummit.com
All sessions - PASS Data Community Summit
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Michael Christofides @michristofides.com · 07/04/2025
Proud to be sponsoring PGDay UK. It’s lovely having a local event and it’s been great each time I’ve attended. It’ll be in London again on September 9th. Let me know if you’ll be there too! P.s. they’re currently looking for speakers (and sponsors!)
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Nik Samokhvalov @samokhvalov.bsky.social · 04/04/2025
Tomas Vondra is one of #PostgreSQL hackers with strong focus on performance and query optimization. Enjoyed this session a lot 📺 www.youtube.com/watch?v=hyMH... 🎙️ postgres.fm/episodes/per... It was inspired by this talk: "Where do performance cliffs come from?" www.youtube.com/watch?v=UzdA...
youtube.com
Performance cliffs | Postgres.FM 140 | #PostgreSQL #Postgres podcast
YouTube video by PostgresTV 💙💛
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Michael Christofides @michristofides.com · 12/03/2025
While editing a podcast episode, I cringed twice whilst being confidently wrong about things. I need to work on that, or I need to stop criticising LLMs (or both!)
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Michael Christofides @michristofides.com · 11/03/2025
I’ve added it as an idea, but it might be a short answer! I think for the vast majority of use cases, the risk of data loss far outweighs the performance benefit. This really good article by Laurenz looks at some alternatives: www.cybertec-postgresql.com/en/commit_de...
cybertec-postgresql.com
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Michael Christofides @michristofides.com · 05/03/2025
Thank you Lukas, much appreciated on both fronts 🙏
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