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evdubsyesterday at 6:04 PM1 replyview on HN

> Recently, a new type of question has entered the database arena: what did this data look like last Tuesday?

This question has been answerable in Dolt for years now.


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quotemstryesterday at 6:09 PM

This kind of DB isn't really answering this question. There's a lot more subtlety to time-span analysis than snapshotting. In particular, aligning two series is non-obvious.

Say you have one time series with CPU-core task switches:

T=1 task=A T=3, task=B, T=5 task=A, ...

... and another of CPU frequency changes ...

T=2 freq_hz=800, T=5 freq_hz=1200, T=6 freq_hz=900

How, in SQL, do you express the question "How many CPU cycles did each task use?"? Try to do it with more complex examples. You'll tear your hair out.

Having worked on this sort of data analysis quite a lot, I'm strongly of the opinion that SQL needs syntax, not just table-valued functions, for expressing questions about timelines.

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