> The COLD updated (old) tuple would be pruned to dead line pointer
> once the tuple becomes DEAD. Normally that would let us reuse the
> tuple storage for other purposes. We do the same for DELETEd tuples.
Oh, I thought only pruned tuples from HOT chains can produce a
"redirect dead" line pointer.
This looks like a problem, since we might end up with a page filled with
LP_DEAD slots, that all have no visibility info and can thus not be
cleaned
by vacuum.
Maybe PageRepairFragmentation when called from HOT should prune less
aggressively. e.g. prune until a max of 1/2 the available slots are
LP_DEAD,
and not prune the rest.
Andreas