Selon Paul Ramsey <[email protected]>: > The PgSQL driver is returning TRUE for OLCFastFeatureCount and then running > "SELECT Count(*)â to fulfill the request. Since that is actually going to > apply a full table scan, itâs not *really* a fast feature count in my > estimation, but perhaps GDAL has a different standard? Whatâs the standard > for a fast feature count? Basically instant (the record count resides in > header metadata or something similar)? Or âfast enough for small thingsâ?
Paul, The standard for "fast" is not well defined I think. Instant would be ideal, but a number of drivers advertize FastFeatureCount when they have a specialized implementation that is faster than the generic one. In that instance the request is run entirely on server side, so this is much faster than the default implementation. It is a bit surprising that PostgreSQL cannot maintain the feature count without going to a full table scan, but I guess there are technical difficulties related to concurrent updates to do so. Even -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
