Simon Riggs wrote:
> We have infrastructure in place to make this work correctly, just need
> to add latestRemovedXid field to xl_btree_vacuum. So that part is easily
> solved.
That's tricky because there's no xmin/xmax on index tuples. You could
conservatively use OldestXmin as latestRemovedXid, but that could stall
the WAL redo a lot more than necessary. Or you could store
latestRemovedXid in the page header, but that would need to be
WAL-logged to ensure that it's valid after crash. Or you could look at
the heap to fetch the xmin/xmax, but that would be expensive.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com