Re: Terminating a SETOF function call sequence

Tom Lane wrote:

>Thomas Hallgren <thhal@mailblocks.com> writes:
>  
>
>>My question is, what happens when the evaluator doesn't need more rows? 
>>Will it:
>>a) call the function with call_cntr >= max_calls?
>>b) continue calling until the set is exhausted anyway?
>>c) simply stop calling?
>>    
>>
>
>(c)
>
>  
>
>>a) seems unlikely since max_calls is set by the user, b) doesn't seem 
>>very optimal, and c) would be very bad since it doesn't give me any 
>>chance to release the resources that where used in order to produce the 
>>rows.
>>    
>>
>
>This is what RegisterExprContextCallback is for.
>
>            regards, tom lane
>  
>
Thanks Tom,
This is exactly what I need. I didn't know that such a callback existed. 
Perhaps it should be mentioned in the documentation chapter that talks 
about SETOF and C-functions?

Regards,
Thomas Hallgren