Heikki Linnakangas wrote:
> Tom Lane wrote:
>> Compared to what it currently takes to check the same tuple (a separate
>> index entry fetch and traversal to the heap page), this is already an
>> enormous performance improvement.
>
> Though keep in mind that we kill index tuples as soon as they're deemed
> to be dead. Nevertheless, I'm not very worried about the cost of
> following the chain either. But that's something we can quite easily
> measure if we want to.
I'm confused now. I though that pruning would be enough to shorten HOT-Chains -
because the root line pointer afterwards points directly to the first live
tuple. But we can *prune* (without actually defragmenting) without holding
a VACUUM-strength lock, right? Or did I get that wrong?
greetings, Florian Pflug
