Re: Updates of SE-PostgreSQL 8.4devel patches (r1268) - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: Updates of SE-PostgreSQL 8.4devel patches (r1268)
Date
Msg-id 200812111759.33900.peter_e@gmx.net
Whole thread Raw
In response to Re: Updates of SE-PostgreSQL 8.4devel patches (r1268)  (Bruce Momjian <bruce@momjian.us>)
List pgsql-hackers
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.


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