Re: SQL/MED - file_fdw

On 12/13/2010 01:31 AM, Itagaki Takahiro wrote:
> On Sat, Dec 11, 2010 at 05:30, Andrew Dunstan<andrew(at)dunslane(dot)net> wrote:
>> On 12/04/2010 11:11 PM, Itagaki Takahiro wrote:
>>> One exports the copy functions from the core, and another
>>> implements file_fdw using the infrastructure.
>> Who is actually going to do this split?
> I'm working for it :-) I extract those functions from copy.c:
>
> - CopyState BeginCopyFrom(Relation rel, const char *filename,
> List *attnamelist, List *options);
> - void EndCopyFrom(CopyState cstate);
> - bool NextCopyFrom(CopyState cstate,
> Datum *values, bool *nulls, Oid *oid);
>
> There was Reset() in file_fdw, but it is not contained in the
> patch. It will be added again if required, but I wonder we might
> need not only reset but also mark/restore a position in a file.
>

Hmm. I don't think that's going to expose enough for what I want to be
able to do. I actually had in mind exposing lower level routines like
CopyReadAttibutesCSV/CopyReadAttributesText and allowing the Foreign
Data Wrapper to manipulate the raw values read (for example from an
irregularly shaped CSV file).

cheers

andrew