Classic example being something like a “users” table that tracks account id, display name (mutable), and profile picture (mutable). And then a “posts” table that has post id, account id, and message text. This allows you to change the display name/picture in one place and it can be used across all posts
The main cost is on the join when you need to access several columns, it's flexible but expensive.
To take full advantage of columnar, you have to have that join usually implicitly made through data alignment to avoid joining.
For example, segment the tables in chunks of up to N records, and keep all related contiguous columns of that chunk so they can be independently accessed:
r0, r1 ... rm; f0, f0 ... f0; f1, f1 ... f1; fn, fn ... fn
immanuwell•1h ago
hilariously•49m ago
There's always a reason for a dev to ship something shitty but when you show you can use 80% less storage for the same operation you can make the accountants your lever.
jklowden•14m ago
1NF removes repeating groups, putting for example data for each month in its own row, not an array of 12 months in 1 row.
Storage efficiency was never the point. IMS had that locked down. Succinctness of expression and accuracy of results was the point. And is: normalization prevents anomalous results.
jerf•34m ago
A nice thing about that point of view is that it fits with your point; redundancy is redundancy whether you look at it with a column-based view or a row-based view.