Re: Tricky bugs in concurrent index build

Tom Lane <tgl@sss.pgh.pa.us> writes:

> I think that's OK, but the whole idea of using an MVCC snap in phase 2
> doesn't work on closer inspection.  The problem is still the same one
> that you need to take (at least) share lock on each tuple you insert
> into the index.  Telling aminsert to check uniqueness implicitly assumes
> the new tuple is live, and without any lock on the tuple you can't
> promise that.  

No wait. It's still "live" according to my snapshot. How could it be possible
for a single snapshot to see two different versions of the same tuple as live?

--  Gregory Stark EnterpriseDB          http://www.enterprisedb.com