On Tue, Dec 4, 2012 at 3:38 PM, Jeff Davis <pgsql@j-davis.com> wrote:
> After reading that thread, I still don't understand why it's unsafe to
> set HEAP_XMIN_COMMITTED in those conditions. Even if it is, I would
> think that a sufficiently narrow case -- such as CTAS outside of a
> transaction block -- would be safe, along with some slightly broader
> cases (like BEGIN; CREATE TABLE; INSERT/COPY).
I haven't looked at the committed patch - which seemed a bit
precipitous to me given the stage the discussion was at - but I
believe the general issue with HEAP_XMIN_COMMITTED is that there might
be other snapshots in the same transaction, for example from open
cursors.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
