On Jun21, 2012, at 13:41 , Andres Freund wrote:
> 3b)
> Ensure that enough information in the catalog remains by fudging the xmin
> horizon. Then reassemble an appropriate snapshot to read the catalog as the
> tuple in question has seen it.
The ComboCID machinery makes that quite a bit harder, I fear. If a tuple is
updated multiple times by the same transaction, you cannot decide whether a
tuple was visible in a certain snapshot unless you have access to the updating
backend's ComboCID hash.
best regards,
Florian Pflug
