> Essentially, we insert a set of columns into a table, and each row fires
> a trigger function which calls a very large stored procedure
For inserting lots of rows, COPY is much faster than INSERT because it
parses data (a lot) faster and is more "data-stream-friendly". However the
actual inserting into the tbale and trigger-calling has to be done for
both.
If the trigger is a "very large stored procedure" it is very likely that
executing it will take a lot more time than parsing & executing the
INSERT. So, using COPY instead of INSERT will not gain you anything.