Florian G. Pflug wrote:
I think you'd want to have a flag per field that tell you if the user has overridden the storage pos for that specific field. Otherwise, the next time you have to chance to optimize the ordering, you might throw away changes that the admin has done on purpose. The same hold true for a pg_dump/pg_reload cycle. If none of the fields had their storage order changed manually, you'd want to reoder them optimally at dump/reload time. If, however, the admin specified an ordering, you'd want to preserve that.
I don't think users should be monkeying with the storage position at all. Decisions about that should belong to the engine, not to users. Providing a user tweakable knob for this strikes me as a large footgun, as well as requiring all sorts of extra checks along the lines you are talking of.
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