Tom Lane wrote:
"Florian G. Pflug" <fgp@xxxxxxxx> writes:
I'm looking for a way to recover deleted or old versions of
accidentally updated rows from a postgres 7.4 database. I've
verified that the relevant tables haven't been vacuumed since
the accident took place.
I was thinking that it might work to patch the clog so that
the offending transactions look like they have never been
comitted? Would that work? How could I patch the clog?
By this point the lost rows are no doubt marked HEAP_XMAX_COMMITTED,
which means that hacking the clog entries wouldn't accomplish anything
by itself --- you'd have to go and unset those hint bits, too.
Given that, you might as well not bother with patching clog; it
wouldn't be any more trouble to unset HEAP_XMAX_COMMITTED and set
HEAP_XMAX_INVALID in each tuple you needed to resurrect.
You'd need a custom tool to do either though :-(
Thanks for you comments - they have been enlighting as usual ;-)
Fortunatly, the customer changed his mind, and now will manually
reenter the lost data.
Thanks anyways,
Florian Pflug
