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> New nullable columns are kryptonite to large Corrosion tables: cr-sqlite needs to backfill values for every row in the table

Is this a typo? Why does it backfill values for a nullable column?

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It seems to be a quirk of cr-sqlite, it wants to keep track of clock values for the new column. It's not backfilling the field values as far as I understand. There is a comment mentioning it could be optimized away:

https://github.com/vlcn-io/cr-sqlite/blob/891fe9e0190dd20917...

I assume it would backfill values for any column, as a side-effect of propagating values for any column. But nullable columns are the only type you can add to a table that already contains rows, and mean that every row immediately has an update that needs to be sent.

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