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0 sats \ 4 replies \ @Lumor 14 Jul 2023 \ on: That moment when you increase query performance by 600x by adding two characters tech

Sheesh. Care to name the guilty SQL implementation?

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21 sats \ 1 reply \ @ek OP 14 Jul 2023

Postgres 14.7

To be fair, it's understandable that postgres doesn't know that extract(epoch from ts) does not change the order of m.ts.
For postgres, it's just a random function which could do anything, I guess. So it can't use the index since it needs to calculate that value for every row first. To spot stuff like this is part of my job as a developer :)

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10 sats \ 0 replies \ @Lumor 14 Jul 2023

Ah, yeah, I guess "overwriting" with "AS ts" in this case would understandably cause such issues, missed that detail. Well done finding it. 🙂

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0 sats \ 1 reply \ @kristapsk 15 Jul 2023

It would be the same on any implementation IMHO. At least it's the same with MySQL too.

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0 sats \ 0 replies \ @Lumor 15 Jul 2023

Yeah, overwriting field names should be avoided if possible.

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