Andres Freund (Tech)

@AndresFreundTec

Postgres Developer, politics nerd, recently moved to US from Germany. Account about tech related things. For politics:

Joined August 2017

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  1. The effect can have on my laptop's power usage is just insane. Having some JS heavy website open more than triples power usage.

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  2. Slides (somewhat repaired) for my talk Asynchronous IO for PostgreSQL (and probably also Direct IO) are at

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  3. Well, that was a bit dramatic. While walking to give the presentation, my laptop shut down. Refused to boot again with something like "No TPM found". Luckily booted after disabling the TPM in bios. Certainly doesn't make for a relaxed start into presenting. Sorry for that!

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  4. Update: That's been fixed since. Thanks

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  5. Upgraded Kernel. Now my experimental io_uring branch of postgres is broken :( Different backends, inheriting io_urings from the postmaster, aren't allowed to submit events anymore. Only consume. Hm.

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  6. *but not when benchmarking.

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  7. When idle my workstation's power supply regulates down its fan so much it stalls. Which then causes it to go to full speed to "recover". At least I think that's the issue. So to work without undue distraction I now have to trigger load in the background, but not benchmarking.

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  8. Probably should look at one of the profile guided binary layout optimizers (e.g.facebook's bolt) and see how much that helps. But I think we also need to look at why our code density/locality is so shitty that we get such a huge number of faults.

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  9. Oh, and besides being complicated: It currently also breaks perf profiles...

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  10. The magic necessary (linker flags to align the text sufficiently, link to libhugetlbfs, editing elf headers with hugeedit --text, setting up accessible hugetlbfs) seems too big for most, but I wonder if there's a way that could be simplified.

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  11. 7.608 M/sec iTLB-loads w/ 50.80% iTLB-load-misses for normal mapping, vs 1.547 M/sec iTLB-loads w/ 48.82% iTLB-load-misses with text mapped as a huge page.

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  12. Interesting. Doing the necessary rituals of sacrifice to get postgres started with the text segment mapped as huge pages yields nearly 10% speedup in a highly concurrent workload.

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  13. New workstation. Finally able to build without typing on an uncomfortably warm keyboard. And without it taking like half a day to build debug + opt builds.

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  14. New laptop without a working ethernet port (only via optional adapter, for thinness) and with a intel wifi card. I could easily work around it (had already ordered a thunderbolt 10gbe ethernet card) - but most people would long have given up at that point.

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  15. Once more I'm concluding that not including non-free firmware on installer images for linux distributions (yes, , looking at you), is extremely self defeating. It's ridiculous to see a harder time installing a nearly entirely free system as a win for software freedom.

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  16. Why on earth did think it was a good idea to name two different microarchitectures "10th Generation Intel® Core™ i* Processors"? And then choose a numbering scheme that doesn't make a ton of sense, on top?

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  17. I know it's a trivial tool, but I just noticed that iprint has been removed from . While there are better tools for almost all uses, they're not as darned simple :). I used it nearly daily. Thanks for maintaining it as long as you did.

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  18. I only wish it allowed negative patterns to move individual directories (e.g. tests) to the end, without having to list everything else.

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  19. I've now set that to src/include/* src/common/* src/port/* config/* src/makefiles/* src/template/* src/backend/* src/fe_utils/* src/bin/* src/interfaces/libpq/* src/pl/* contrib/* src/interfaces/* doc/* src/test/* allowing me to see the "most crucial" (for me) things first.

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  20. Random useful developer discovery for postgres development: git's diff.orderFile option. Allows to change the order in which different files appear in diffs.

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