[sfg75]

That's a fair point. Indeed we started looking at doing aggregations across raw events, before realizing this was probably ill fated.

It's very possible we could have done the same with RedShift but it didn't seem obvious how. With Citus offering extensions like topn and hll we however quickly saw how that could work for us.

Thanks for the link btw!

[al_james]

Yeah, thats a good point. Redshift does not have the same level of 'probabilistic counting' functions, that can be used from rollups. Redshift does have HLL (SELECT APPROXIMATE COUNT(*)) however that can only be applied when scanning the full data, I am not sure its possible to store a HLL object in a rollup and later aggregate them.