Re: [HACKERS] CTIDs invalidations and dropping columns.

2006-07-11 Thread Martijn van Oosterhout
On Tue, Jul 11, 2006 at 01:50:40AM +0300, Tzahi Fadida wrote: As i understand rowids, i.e ctids, are supposed to allow for fast access to the tables. I don't see the rational, for example, when casting some attributes, to blank the ctid. So it is not exactly the same, but it still came from

Re: [HACKERS] CTIDs invalidations and dropping columns.

2006-07-11 Thread Tzahi Fadida
On Tuesday 11 July 2006 17:27, Martijn van Oosterhout wrote: On Tue, Jul 11, 2006 at 01:50:40AM +0300, Tzahi Fadida wrote: As i understand rowids, i.e ctids, are supposed to allow for fast access to the tables. I don't see the rational, for example, when casting some attributes, to blank

[HACKERS] CTIDs invalidations and dropping columns.

2006-07-10 Thread Tzahi Fadida
Hi, First, i use CTIDs to immensely speed up my function which is inherently slow because of the problem itself. I have a question about CTID invalidation when you open a read only cursor using SPI. Why does it at all happens? Why is it so important to invalidate a ctid of a read only query

Re: [HACKERS] CTIDs invalidations and dropping columns.

2006-07-10 Thread Martijn van Oosterhout
On Mon, Jul 10, 2006 at 11:47:23PM +0300, Tzahi Fadida wrote: Hi, First, i use CTIDs to immensely speed up my function which is inherently slow because of the problem itself. I have a question about CTID invalidation when you open a read only cursor using SPI. Why does it at all happens?

Re: [HACKERS] CTIDs invalidations and dropping columns.

2006-07-10 Thread Tzahi Fadida
On Tuesday 11 July 2006 00:35, Martijn van Oosterhout wrote: On Mon, Jul 10, 2006 at 11:47:23PM +0300, Tzahi Fadida wrote: Hi, First, i use CTIDs to immensely speed up my function which is inherently slow because of the problem itself. I have a question about CTID invalidation when you

Re: [HACKERS] CTIDs invalidations and dropping columns.

2006-07-10 Thread Tom Lane
Martijn van Oosterhout kleptog@svana.org writes: You're talking about invalidation as if it's something someone deliberately does. That's incorrect. The t_ctid field is filled in if and only if the tuple is exactly the on disk tuple. Otherwise it's a new tuple, which by definition does not