[postgis-users] Re: Enormous file geodatabase feature class

[Obe, Regina]

 > Thanks Regina and Webb. Regina, do you actively use
> PostGIS for City of Boston GIS work?
Yes - well just one specific department (and even here there is a mix of
MapInfo and ESRI, but PostGIS/PostgreSQL serves better for analytical
stuff and integrating with other database and web apps) 
- the rest of the City 
departments are highly ESRI centric as I guess could 
be said about most city and federal government.


> Have you thought about using inherited tables and
> constraint exclusion. It has a couple of advantages
> over loading everything in one table
> 1) Your master table can have fewer fields than the
> other tables, that way you can have the core fields
> in master and still maintain some of
> the other fields for the counties that vary.

> Haven't thought about it, but thanks to you I now
> am--thanks for the suggestion. Is this something
> you've actively used? Can you give a real-world
> example? Have any others here used inherited tables in
>  this way, and can you give an example?

I've used a couple of times - for here - we have a ParcelTime master
table where
each years parcels are stored in a separate table - think we have about
6 years worth - not amounting to much (as far as GIS is concerned) - but
comes in handy as you can easily geocode projects that were against
parcels that have been destroyed or reparcelized (often as a result of
the project) or figure out when a parcel last existed with a query like 

SELECT DISTINCT ON(pid)
	PID,pid_year,  the_geom 
	FROM parceltime
	ORDER by pid, pid_year DESC

Which surprisingly runs faster than I would expect

(or figure out what it was folded or built out of)

But yet doesn't impact speed for looking at latest year data since we
have a constraint on the year field. (So this is partitioned by time
rather than space)

Also using inherited tables for a non-city project among other things -
I think closer
to what you are doing (which does use space partitioning).  

For both of these - the unheritability of foreign key constraints don't
play too much of an issue and in the situation like where Webb
mentioned, I usually have paired tables so there are workarounds for
that issue at anyrate.

Hope that helps,
Regina

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