Robert Haas <robertmhaas@gmail.com> writes:
> On Mon, Nov 21, 2022 at 12:38 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> What it's restricting is the number of heap page fetches, which
>> might be good enough. We don't have a lot of visibility here
>> into how many index pages were scanned before returning the next
>> not-dead index entry, so I'm not sure how hard it'd be to do better.
> Oh. That's really sad. Because I think the whole problem here is that
> the number of dead index entries can be huge.
If they're *actually* dead, we have enough mitigations in place I think,
as explained by the long comment in get_actual_variable_endpoint.
The problem here is with still-visible-to-somebody tuples. At least,
Jakub's test case sets it up that way.
regards, tom lane