软件包: postgresql-10-ogr-fdw (1.0.5-2)

PostgreSQL foreign data wrapper for OGR

OGR is the vector half of the GDAL spatial data access library. It allows access to a large number of GIS data formats using a simple C API for data reading and writing. Since OGR exposes a simple table structure and PostgreSQL foreign data wrappers allow access to table structures, the fit seems pretty perfect.

This implementation currently has the following limitations:

 * Only non-spatial query restrictions are pushed down to the OGR driver.
   PostgreSQL foreign data wrappers support delegating portions of the SQL
   query to the underlying data source, in this case OGR. This implementation
   currently pushes down only non-spatial query restrictions, and only for the
   small subset of comparison operators (>, <, <=, >=, =) supported by OGR.
 * Spatial restrictions are not pushed down. OGR can handle basic bounding box
   restrictions and even (for some drivers) more explicit intersection
   restrictions, but those are not passed to the OGR driver yet.
 * OGR connections every time Rather than pooling OGR connections, each query
   makes (and disposes of) two new ones, which seems to be the largest
   performance drag at the moment for restricted (small) queries.
 * All columns are retrieved every time. PostgreSQL foreign data wrappers don't
   require all columns all the time, and some efficiencies can be gained by
   only requesting the columns needed to fulfill a query. This would be a
   minimal efficiency improvement, but can be removed given some development
   time, since the OGR API supports returning a subset of columns.