[arp242]

> plain old PG coming ahead on quite a few

I found that is common among these types of databases (e.g. Citus, Timescale, etc.) which perform well under very specific conditions, and worse for many (most?) other things, sometimes significantly worse.

That said, Hydra does take up ~17.5G for that benchmark and "PostgreSQL tuned" about 120G, the insert time is ~9 times faster, and "cold run" is quite a bit faster too. It's only "hot run" that shows a fairly small difference. I think it's fair to say Hydra "wins" that benchmark.

> Is Hydra a fork of Citus columnar storage?

Yes: "Hydra Columnar is a fork from Citus Columnar c. April, 2022".

[riku_iki]

> Hydra does take up ~17.5G for that benchmark and "PostgreSQL tuned" about 120G

you can run pg on compressed filesystem

[arp242]

I'm sure you can, but AFAIK neither uses compression in that benchmark so it's a fair comparison. Even if filesystem compression would reduce that to 17.5G (doubtable), it won't be free in terms of CPU cycles, and no matter what it's still ~120G to load in memory, bytes to scan/update, etc.

[riku_iki]

my bet is that hydra uses compression inside already, otherwise it is hard to explain where difference comes from.

> it won't be free in terms of CPU cycles

it can reduce IO traffic significantly, and it can be very positive trade off depending on circumstances.

[arp242]

I had assumed that PostgreSQL is so much larger because it creates heaps of indexes (which is probably also why inserts are so much slower for it), but I don't really have a good way to confirm that quickly.

[riku_iki]

one can choose to not create "heaps of indexes".

[arp242]

At which point your performance will drop like a brick for these types of queries – I'm pretty sure these indexes weren't added for the craic.