Re: Reducing the overhead of NUMERIC data

Stephan Szabo wrote:
> 
> On Thu, 3 Nov 2005, Simon Riggs wrote:
> 
> > On Wed, 2005-11-02 at 19:12 -0500, Tom Lane wrote:
> > > Andrew Dunstan <andrew@dunslane.net> writes:
> > > > Could someone please quantify how much bang we might get for what seems
> > > > like quite a lot of bucks?
> > > > I appreciate the need for speed, but the saving here strikes me as
> > > > marginal at best, unless my instincts are all wrong (quite possible)
> > >
> > > Two bytes per numeric value is not a lot, agreed.
> >
> > I'm optimising for Data Warehousing. If you have a very large table with
> > a higher proportion of numerics on it, then your saving can be >5% of
> > tablesize which could be very useful. For the general user, it might
> > produce less benefit, I accept.
> >
> > At the moment we've established we can do this fairly much for free.
> > i.e. nobody cares about the drop in digits (to 255) and the other coding
> 
> I don't believe the above is safe to say, yet. AFAICS, this has been
> discussed only on hackers (and patches) in this discussion, whereas this
> sort of change should probably be brought up on general as well to get a
> greater understanding of whether there are people who care. I expect that
> there won't be, but given that I'm still not sure what the plan to support
> applications upward is for this change, I think it's probably a good idea
> to query a larger segment of the population.

Agreed.  With the proposal, we are saving perhaps 5% storage space for
numeric fields, but are adding code complexity and reducing its possible
precision.

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