On 06/01/2018 12:25 PM, Guyren Howe wrote:
On Jun 1, 2018, at 10:16 , Olivier Gautherot <oliv...@gautherot.net
<mailto:oliv...@gautherot.net>> wrote:
You will get a benefit in terms of space only if the optional fields in
the second table exist in a reduced number of instances - and the second
table is significantly wider. This can make a difference on big tables
but this gain may be offset by the cost of the join. In this perspective,
I don’t think that there is a clear benefit or drawback: it should be
evaluated on a case-by-case basis.
It seems to me that people take time to *catch up with modern hardware
reality. SSDs reduce seek time to virtually zero.* Surely, joins are now
much, much cheaper. If so, I’m inclined to describe wide tables as a
premature optimization.
Sure, SSDs are uber-wonderful, but a rack full of rotating media is still
going to be a lot cheaper and have a lot more capacity than a rack full of
SSDs, and that makes all the difference...
--
Angular momentum makes the world go 'round.
