Re: Fetching from psql procedures

Hi

2015-11-19 14:51 GMT+01:00 Marc Mamin <M(dot)Mamin(at)intershop(dot)de>:

> Hi,
>
> I'm looking for a way to build large xml documents based on a set of
> tables, hence using recursive queries.
>
>
> something like:
>
> FOR rec1 IN ...
> FOR rec2 IN ...
>
> RETURN QUERY select '<foo>
> FOR rec3 IN ...
>
> RETURN QUERY select (XMLELEMENT (...))::text
>
> END LOOP;
> RETURN QUERY select '</foo>
>
> END LOOP;
> END LOOP;
>
>
>
> but if I wrap this in a function, it seems that I won't get a result
> before the whole document is prepared.
>
> Is there any way to stream the result as it get produced ?
> or does anybody knows of a good tutotial for a task like this ?
>

you can try CTE Common Table Expression. It isn't possible with plpgsql :(

Theoretically you can write C extension where SRF function can returns data
continually.But plpgsql function using local stack and returns data as
block.

Regards

Pavel

>
>
> thanks and best regards,
>
> Marc Mamin
>
>
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