Re: creating WITH HOLD cursors using SPI

Abhijit Menon-Sen wrote:

>Hi.
>
>I've been working on making it possible for PL/Perl users to fetch large
>result sets one row at a time (the current spi_exec_query interface just
>returns a big hash).
>
>The idea is to have spi_query call SPI_prepare/SPI_open_cursor, and have
>an spi_fetchrow that calls SPI_cursor_fetch. It works well enough, but I
>don't know how to reproduce spi_exec_query's error handling (it runs the
>SPI_execute in a subtransaction).
>
>To do something similar, I would have to create a WITH HOLD cursor in my
>spi_query function. But SPI_cursor_open provides no way to do this, and
>it calls PortalStart before I can set CURSOR_OPT_HOLD myself.
>
>Suggestions?
>
>
>  
>

Abhijit,

Thinking and reading about this some more, I think we should not try to 
mimic the error handling of the existing mechanism. Let's just provide a 
separate API using SPI_prepare/SPI_open_cursor/SPI_cursor_fetch, and 
leave the current mechanism in place - it's useful enough on small 
resultsets.

Does that make sense? If so, can you do that, or give me what you have 
and let me bang on it?

cheers

andrew