Alvaro Herrera wrote:
> Jan Wieck wrote:
> > On 6/25/2006 10:12 PM, Bruce Momjian wrote:
> > >When you are using the update chaining, you can't mark that index row as
> > >dead because it actually points to more than one row on the page, some
> > >are non-visible, some are visible.
> >
> > Back up the truck ... you mean in the current code base we have heap
> > tuples that are visible in index scans because of heap tuple chaining
> > but without index tuples pointing directly at them?
>
> I don't know where this idea came from, but it's not true. All heap
> tuples, dead or otherwise, have index entries. Unless the idea is to
> extend update chaining to mean something different from the current
> meaning.
It does mean something different. Single-Index-Tuple Chain (CITC) is a
special type of update chaining where the updates are all on the same
row, and a single index entry points to the entire chain.
-- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +