> Can you explain to me what particular cases postgresql's decimal type cannot handle properly _and_ conveniently?
I entirely agree that numeric is a good solution for this case.
But to try to answer your question nevertheless: I'd say there is potential for storage density and math performance issues. You really need to have a number of numerics for each row, and a lot of rows to make storage density matter. If you do a lot of aggregates over numerics you definitely can notice the CPU overhead of them over say a plain float. But most of the time that doesn't matter.
I entirely agree that numeric is a good solution for this case.
But to try to answer your question nevertheless: I'd say there is potential for storage density and math performance issues. You really need to have a number of numerics for each row, and a lot of rows to make storage density matter. If you do a lot of aggregates over numerics you definitely can notice the CPU overhead of them over say a plain float. But most of the time that doesn't matter.