Re: [HACKERS] Index corruption with CREATE INDEX CONCURRENTLY

On Fri, Feb 17, 2017 at 11:15 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

> Ah, nah, scratch that.  If any post-index-build pruning had occurred on a
> page, the evidence would be gone --- the non-matching older tuples would
> be removed and what remained would look consistent.  But it wouldn't
> match the index.  You might be able to find problems if you were willing
> to do the expensive check on *every* HOT chain, but that seems none too
> practical.

If the goal is just to detect tuples that aren't indexed and should
be, what about scanning each index and building a TIDBitmap of all of
the index entries, and then scanning the heap for non-HOT tuples and
probing the TIDBitmap for each one?  If you find a heap entry for
which you didn't find an index entry, go and recheck the index and see
if one got added concurrently.  If not, whine.