Re: [HACKERS] libpq cursor support?

[Tom Lane]

Andrew Dunstan <[EMAIL PROTECTED]> writes:
> I was looking at the TODO list today and noticed that we don't seem to 
> have an item for libpq cursor support.

I doubt that "cursor support" is what you want, but rather access to the
partial-fetch capability of extended query protocol.  But that's an
implementation detail.  The real question here is what would a sane
libpq API look like for partial result sets?  AFAIR no one has put
forward a specific proposal.

regards, tom lane

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Re: [HACKERS] libpq cursor support?

[Martijn van Oosterhout]

On Wed, Mar 21, 2007 at 05:32:21PM -0400, Andrew Dunstan wrote:
> 
> I was looking at the TODO list today and noticed that we don't seem to 
> have an item for libpq cursor support. I see it's been discussed in the 
> past ( e.g. 
> http://archives.postgresql.org/pgsql-interfaces/2000-09/msg00082.php ). 
> We have occasional reports of libpq apps blowing up on huge resultsets, 
> so ISTM this would be a good thing to have on the list.

There are a few issues here. Right now, if you code your client
correctly, you can retreive partial resultsets before the query has
finished executing (sort of streaming). However, it is a bit clumsy.

If you get libpq to wrap each query with a DECLARE CURSOR, you'd have
to teach it what queries can and can't have it. It would be nicer to do
it at the protocol level, but I don't know if that's supported.

Have a nice day,
-- 
Martijn van Oosterhout  http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to 
> litigate.


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[HACKERS] libpq cursor support?

[Andrew Dunstan]

I was looking at the TODO list today and noticed that we don't seem to 
have an item for libpq cursor support. I see it's been discussed in the 
past ( e.g. 
http://archives.postgresql.org/pgsql-interfaces/2000-09/msg00082.php ). 
We have occasional reports of libpq apps blowing up on huge resultsets, 
so ISTM this would be a good thing to have on the list.


I see this item under libpq:

 . Allow statement results to be automatically batched to the client

but I'm not sure that would be as useful.

Thoughts?

cheers

andrew

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