[postgis-devel] Is postgres - postgis able to support estimated metadata for views?

[HAUBOURG]

Hi,
this is my first post here, so please redirect me to the right list if I'm not in the right place.

I found no answer in google or osgeo lists so, here is my concern:

 All our spatial datasets lie in Postgis. We mainly use SQL views to serve spatial data to our clients (QGIS, QGIS server,  Mapserver, Talend spatial...) , firstly because many datasets are in relational object models, secondly because we serve some geographical subsets to differents apps and we can't afford to have replication of the same tables for different locations.

We already optimized index, clustered table on those tables so that attribute queries on subsets are as fast as classical smaller tables.

QGIS / qgis server clients require to extract metadatas such as estimated extent, fields and data types, primary keys and geometry types. This is rocket fast on tables with metadata's updated with autovacuum.

Views do not support such metadatas, then those information require to scan fields, and geometries. Loading layers from views starts to be a severe bottleneck here with increasing spatial resolution of datasets.

QGIS desktop slows down when loading views only, so user have to wait 10 -20 seconds once only for medium size projects, when QGIS server seems to query those metadata on each tile query, and is fairly unusable woth such views. Mapserver does not seem to need those information, and runs smoothly.

My question now:
Is there any technical option available in Postgres / Postgis architecture to head forward handling views metadata ?
If possible, could you give me some tips on how to have it land in the project.
I should be able to fund developers on that - no free work asked her !

Thanks for your lights

all the best
Régis

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