Re: should INSERT SELECT use a BulkInsertState?

One loose end in this patch is how to check for volatile default expressions.

copyfrom.c is a utility statement, so it can look at the parser's column list:
COPY table(c1,c2)...

However, for INSERT, in nodeModifyTable.c, it looks like parsing, rewriting,
and planning are done, at which point I don't know if there's a good way to
find that. The default expressions will have been rewritten into the planned
statement.

We need the list of columns whose default is volatile, excluding columns for
which a non-default value is specified.

INSERT INTO table (c1,c2) VALUES (1,default);

We'd want the list of any column in the table with a volatile default,
excluding columns c1, but not-excluding explicit default columns c2 or any
implicit default columns (c3, etc).

Any idea ?

--
Justin