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Comment by gleenn | Hacker News Reader

It's definitely an interesting approach but the problem is now you have to change all your queries and undeleting get more complicated. There are strong trade-offs with almost all the approaches I've heard of.

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With partitioning? No you don't. It gets a bit messy if you also want to partition a table by other values (like tenant id or something), since then you probably need to get into using table inheritance instead of the easier declarative partitioning - but either technique just gives you a single effective table to query.

Pg moves the data between positions on update?

If you are updating the parent table and the partition key is correctly defined, then an update that puts a row in a different partition is translated into a delete on the original child table and an insert on the new child table, since v11 IIRC. But this can lead to some weird results if you're using multiple inheritance so, well, don't.

I believe they were just pointing out that Postgres doesn't do in-place updates, so every update (with or without partitions) is a write followed by marking the previous tuple deleted so it can get vacuumed.

That’s not at all what the child to me was saying in even a generous reading.

But HOT updates are a thing, too.

What do you think they were saying? I don't see any other way to read it.

HOT updates write to the same tuple page and can avoid updating indexes, but it's still a write followed by marking the old tuple for deletion.

> Pg moves the data between positions on update?

I assume they typo'd "partitions" as "positions", and thus the GP comment was the correct reply.

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