Re: BUG #11638: Transaction safety fails when constraints are dropped and analyze is done

On Wed, Oct 15, 2014 at 2:12 PM, Andres Freund <andres(at)2ndquadrant(dot)com>
wrote:

> I'm not sure which danger you're seeing here. Imo we need to choose
> between heap_inplace/heap_update for VACUUM/ANALYZE because one is
> allowed to run in a transaction, and the other is not. It simply *can't*
> be safe for ANALYZE to set things like relhastriggers = false using
> heap_inplace().
> There's problems with both it rolling back and thus undoing the action
> that allowed relhastriggers = false to be set and scenarios where it's
> not ok that other backends can see that value before the transaction
> committed.

Hm, I was wondering about the potential effects of VACUUM FULL or VACUUM
ANALYZE, but as they cannot run in a tx block... Btw, I have just put my
hands on this code and made the attached to make vac_update_relstats able
to do a transactional update. It looks to work fine with only a check on
the flags of vacuum statement.
Regards,
--
Michael