Recent submissions

Comment · 9 days ago
Comment · 1 month ago
29 footnotes? What is this, Infinite Jest?
Comment · 2 months ago
Comment · 3 months ago
Wow! At first, I expected this to be a demonstration of an AI playing rocket league, but I rapidly realized this is actually a model simulating rocket league. Wild! It feels just like the real game.
Comment · 1 year ago
Comment · 1 year ago
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Comment · 2 years ago
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Comment · 2 years ago
Yeah we should be more clear in our description about how our footers differ from Parquet. Parquet is a bit more prescriptive; for example, it requires row groups which are not required by Vortex. If you have a column with huge values and another column of 8 bit ints, they can be paged separately, if you like.
Comment · 2 years ago
Yeah, you and us are on the same page (heh). We don’t want the format to require row grouping. The file format has a layout schema written in a footer. A row group style layout is supported but not required. Specification of the layout will probably evolve, but currently the in-memory structure becomes the on-disk structure. So, if you have a ChunkedArray of StructArray of ChunkedArray you’ll get row groups and pages within them. If you had a StructArray of ChunkedArray you’ll just get per-column pages.

I’m working on the Python API now. I think we probably want the user to specify, on write, whether they want row groups or not and then we can enforce that as we write.

Comment · 2 years ago
Comment · 2 years ago
Unless I’m misreading, the first two references support the idea that vacancy rates are too low but don’t comment on why.

The last reference indeed argues in favor of too much financialization of housing units but that blog is also tripping a lot of my crackpot alarms.

Can you succinctly explain why you believe the low vacancy rates in major metros (which I think we agree is the cause of high rents / purchase costs) are caused primarily by units which are intentionally held empty despite demand?

In partial defense of your assertion, the FRED data does show that 1/4 to 1/3 of vacant units are for sale or rent at any given time.

https://fred.stlouisfed.org/graph/?g=1oeIe

Total vacancy rate seems to hover around 10%? Rentable and buyable unit rates are an order of magnitude lower.

I’m not convinced that the Fed owning a bunch of mortgages is evidence that private companies bought homes and aren’t renting them. Wasn’t that a bail out to prevent people from losing their homes (because the companies owning the homes weren’t solvent and I guess if the company fails maybe you get foreclosed? I’m not sure why we did things the way we did in 08)

Could not the explanation also be that a lot of homes are in places that lack demand and therefore the owners don’t bother putting them up for sale or rent?

https://fred.stlouisfed.org/graph/?g=1oeII

Comment · 2 years ago
Thanks for the reply and clarification! That’s an impressive throughput. Am I interpreting the behavior correctly to think that: your code has one branch per int and that branch will be predicted well when your integers are all of similar magnitude?

I never fully groked the Zipf distribution but am I correct to conclude the worst case for vu128 would be alternating integers on either side of the branch condition?

Thanks for the link to the slides, also clever!

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