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throwmeaway2232

2 karma · joined April 13, 2023

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throwmeaway2232··on We have successfully completed our migration to RAM-only VPN infrastructure
or liquid nitrogen. https://en.wikipedia.org/wiki/Cold_boot_attack
throwmeaway2232··on The surprising impact of medium-size texts on PostgreSQL performance (2020)
I was pretty confused by the index performance when getting ~50% of the table.

I think what's happening is that since the tuples in the medium table are larger, less are stored on each page. Just looking at the sizes of the tables:

medium: 977 MB

Large: 25 MB

we can assume that the medium query had to access 39.08 ( 977 / 25 ) * more pages.

medium time: 3198.539

large time: 85.74

3198.539 / 85.74 = 37 which seems to track.

What was confusing me is that I thought that the io would take longer for the large text objects because there's more of it. I think that the reason why this isn't the case is because TOAST is probably optimised to make fewer calls to io, but they tend to be much larger. it's not necessarily the size of the data, but rather how many syscalls you have to make to request the data.

pretty unsure about this, but it seems to make sense now.

throwmeaway2232··on Ask HN: What are your optimistic takes on the SWE job market post AI?
if LLM's improve your productivity, you'll be more likely to start your own startup. Why let your employer reap the benefits of your improved productivity?

Optimistically, no one would need to work as an SWE, since they could bootstrap companies at the speed of light.