> Was just curious if anyone was able to come up with any sort of method to > test whether an index was corrupted by this bug, other than just waiting > for bad query results? We've used concurrent index rebuilding quite > extensively over the years to remove bloat from busy systems, but > reindexing the entire database "just in case" is unrealistic in many of our > cases.
As stated, if the CREATE INDEX operates on columns that are previously already indexed (which is normally the case when you rebuild because of bloat) then there is no chance of index corruption.
Scanning indexes+tables is just as load-intensive as rebuilding the indexes anyway. You don't save any work. I suppose it can be a problem if you have an index big enough that it doesn't fit on your remaining free space (but in that case you have a pre-existing problem which you should solve anyway).
It's not the load I'm worried about, it's the locks that are required at some point during the rebuild. Doing an index rebuild here and there isn't a big deal, but trying to do it for an entire heavily loaded, multi-terabyte database is hardly trivial. And I'd say doing a scan is far less invasive than actually rebuilding the index since little to no writing is actually being done.
I can understandable if it's simply not possible, but if it is, I think in any cases of data corruption, having some means to check for it to be sure you're in the clear would be useful.