[postgis-users] Loading Tiger2007fe data - Thoughts onusinginherited tables

[Obe, Regina]

>> Interestingly enough there does appear to be some speed benefit (at
>> least I've noticed) with using inheritance even without constraint
>> exclusion.  My guess is something along the line of parallel reads.

>I'd be interested in real, repeatable, performance metrics which show
>this.  Certainly I'm not aware of PG doing any kind of multi-threaded
>reads and views will benefit from the shared memory cache just the same
>as inheritance.

I suspect the performance of multiple tables vs. inheritance without
constraint exclusion would probably achieve the same effect.  It could
very well be the shared memory. I didn't run an absolute scientific
test.

So are you planning to write some sort of union all view or something
more sophisticated like an intelligent view. Not sure if that is even
possible though I have dreamed about it.  I haven't figured out how to
see the where condition of a view to act on it before it is applied.  If
that were possible you can wrap your own constraint exclusion logic in
the body of an intelligent view.

I would still use inheritance if nothing but for the mere ease of
management it offers.  From a management perspective, inheritance verses
keeping track of multiple tables has made my life a ton simpler.

For example check constraints are inherited so I do addgeometry once.
My table creates are trivial because they are just
CREATE TABLE ... INHERITS

If I don't like the name of a field, I change it in the parent table and
it automagically gets changed in the child tables - no fussing about
changing each table individually (or writing a script to do it). If I
realize I need a field - I add it to the parent and the children
inherit.

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