We noticed that in databases with lots of tables, OGR throws some pretty crazy 
SQL at the database, and things get slow and the source of the problem seems to 
be here:

http://trac.osgeo.org/gdal/browser/trunk/gdal/ogr/ogrsf_frmts/pg/ogrpgdatasource.cpp#L851

Which in addition to being a big query on system tables joins back to 
geometry_columns, which is, itself now a big query on system tables. I think 
that’s the main problem. Probably either the query should just use the system 
tables alone, and take advantage of the PostGIS geometry_columns view code as a 
guide

http://trac.osgeo.org/postgis/browser/trunk/postgis/postgis.sql.in#L4980

The only trick is, I guess, figuring out which versions of PgSQL particular 
system table code will work against. The main dividing line for PostGIS is 
between versions 1 and 2.  What’s the minimum supported version of PgSQL for 
OGR?

P. 


--  
http://postgis.net  
http://cleverelephant.ca


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