Re: removing PD_ALL_VISIBLE

On Thu, May 30, 2013 at 09:47:22AM -0400, Robert Haas wrote:
> Well, as Heikki points out, I think that's unacceptably dangerous.
> Loss or corruption of a single visibility map page means possible loss
> of half a gigabyte of data.
> 
> Also, if we go that route, looking at the visibility map is no longer
> an optimization; it's essential for correctness.  We can't decide to
> skip it when it seems expensive, for example, as Jeff was proposing.

Isn't the visibility map already required for proper return results as
we use it for index-only scans.  I think the optimization-only ship has
sailed.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +