Peter Eisentraut <peter_e@gmx.net> writes:
> What does the error message
> failed to re-find parent key in "tablename_pkey"
> mean? This happens reproducibly during VACUUM on a certain table.
If it happens during vacuum (not vacuum full) then it must be coming
from _bt_pagedel, and it means that _bt_pagedel could not find the
parent-level btree entry for the page it wants to remove from the index.
> Would REINDEX fix it? Anything else we should check?
REINDEX would fix it, but it would be interesting to find out what the
actual cause is. I think we've seen one or two similar reports
previously in 7.4.*, but there's never been enough info to track
it down. Any chance of going in with a debugger, or capturing a
tarball image of the database for someone else to look at?
regards, tom lane