Re: Updates of SE-PostgreSQL 8.4devel patches (r1268)

On Thursday 11 December 2008 04:52:51 Bruce Momjian wrote:
> > > We do have a per-row HEAP_HASOID bit, so I wonder if we can have a
> > > HEAP_HASSEC bit too.  Right now the HEAP_HASOID is controlled by the
> > > CREATE/ALTER table;
> >
> > The current patch add HEAP_HASSECURITY bit to t_infomask. :-)
> > When it is false, its security field is not available and not allocated.
>
> Good.

This is probably OK, but if you want to save a bit or generalize it, it might
be worth considering using the normal null bitmap and nullity everywhere
instead of individual HEAP_HASTHISORTHAT bits for every feature.

Of course, if we expect that most rows will have no security information, this
tradeoff might end up on the wrong side of the equation.