>> Of course, I want this so I could construct a text array from the read in
>> data, but I could also imagine a foreign data wrapper wanting to mangle the
>> data before handing it to postgres, say by filling in a field or hashing it.
> Could you explain the actual use-cases and examples? I think we need to have
> SQL-level extensibility if we provide such flexibility. I guess typical users
> don't want to write functions with C for each kind of input files.
>
> Note that pg_bulkload has a similar feature like as:
> CREATE FUNCTION my_function(...) RETURNS record AS ...;
> COPY tbl FROM 'file' WITH (make_record_from_line = my_function)
Umm, where? I can't find this in the documentation
<http://pgbulkload.projects.postgresql.org/pg_bulkload.html> nor in the
source code. And how would module like that provide an extra copy option?
The object, as I have explained previously, is to have a FDW that
returns a text array from a (possibly irregularly shaped) file.
So, given this file:
1,,2,3
4,5,6
select t[4] as a,t[2] as b from my_fdw_table;
would return
a | b
-----
3 | | 5
cheers
andrew