Hi Szymon, Kevin,
The offset is the order of a tuple in a Sequential Scan.
What I want to do is, for a given key return the tuples that Index scan can find, and return the rest tuples by a seq scan. So, I need to know which tuples have been returned by maintain a bitmap, and to avoid return the same tuple twice.
If I can know the offset of a tuple in the order of file scan, then I can force the seq scan to skip it.
By ctid, can I know how much tuples are in a block, is it an constant?
I think a more general solution would be build a hash table on ctid.
What do you think?
Thanks
--
Pei
On Tue, Sep 21, 2010 at 5:44 PM, Szymon Guz
<mabewlun@gmail.com> wrote:
On 21 September 2010 23:02, Pei He
<hepeimail@gmail.com> wrote:
Hi,
When I using an index scan, can I get the offset of the tuple in the table?
Thanks
--
Pei
What do you mean by "the offset in the table"?