What you are describing is called "internal fragmentation" and it's always a problem at some level in any system. There are tons of ways to mitigate the proble

What you are describing is called "internal fragmentation" and it's always a problem at some level in any system. There are tons of ways to mitigate the problem including variable-length data, out-of-line storage, and compression. Postgres does those things, but I suppose there's always room to improve. Best to just see how much storage a given table uses, and see if it's a problem.