The following functions fail:
create or replace function docopy(int[]) returns int as
$$
copy (select unnest($1)) to stdout;
select 0;
$$ language sql;
ERROR: there is no parameter $1
create or replace function docopy(int[]) returns int as
$$
begin
copy (select unnest($1)) to stdout;
end;
$$ language plpgsql;
ERROR: SPI_execute_plan failed executing query "copy (select unnest(
$1 )) to stdout": SPI_ERROR_COPY
this error is expected i guess, plpgsql doesn't support copy to stdout.
create or replace function docopy(_stuff int[]) returns int as
$$
begin
copy (select unnest(_stuff)) to '/tmp/scratch';
end;
$$ language plpgsql;
ERROR: there is no parameter $1
Also, copy does not allow variable substitution for the destination
file. Dynamic sql is one work around, but EXECUTE USING does not
work:
create or replace function docopy(_stuff int[]) returns int as
$$
begin
execute 'copy (select unnest($1)) to ''/tmp/scratch''' using _stuff;
end;
$$ language plpgsql;
ERROR: there is no parameter $1
merlin
