Re: modifying the tbale function - Mailing list pgsql-hackers

From Islam Hegazy
Subject Re: modifying the tbale function
Date
Msg-id BAY21-DAV86F8169396BEB62E111AED3770@phx.gbl
Whole thread Raw
In response to modifying the tbale function  ("Islam Hegazy" <islheg@hotmail.com>)
List pgsql-hackers
Returning k rows would be a reasonable solution but which functions need to 
be modified to achieve this.


----- Original Message ----- 
From: "Neil Conway" <neilc@samurai.com>
To: "Andrew Dunstan" <andrew@dunslane.net>
Cc: "Martijn van Oosterhout" <kleptog@svana.org>; "Islam Hegazy" 
<islheg@hotmail.com>; <pgsql-hackers@postgresql.org>
Sent: Sunday, March 18, 2007 4:57 PM
Subject: Re: [HACKERS] modifying the tbale function


> Andrew Dunstan wrote:
>> I'm not convinced it would be a huge gain anyway. Switching madly in and 
>> out of the perl interpreter at least is a known performance problem, IIRC
>
> Returning control to the backend for every row returned would likely be 
> excessive, but you could return once every k rows and get most of the 
> benefits of both approaches (k might be on the order of 1000). The problem 
> with the current approach is that it makes returning large result sets 
> from PL functions very expensive, since they need to be spooled to disk.
>
> As for using threads, that's pretty much a non-starter: we can't safely 
> allow calls into the backend from multiple concurrent threads, and I doubt 
> that will chance any time soon.
>
> -Neil
>
>
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