Why doesn't ogr2ogr support the PostgreSQL schema search path?

Question

I have a PostGIS database with a table vector_data in schema vectors, and the vectors schema is listed in the database search_path. In GDAL <= 3.0.4, this command works fine (that is, the vector_data table is reachable because it's in the search_path):

ogr2ogr -f GeoJSON "test.geojson" PG:"host=localhost port=5432 user=username password=password" -sql "SELECT ST_AsGeoJSON(geom) FROM vector_data LIMIT 1;"

However, in GDAL >= 3.1.0, that same command fails as if the search_path is being ignored:

ERROR 1: ERROR:  relation "vector_data" does not exist
LINE 1: ...LCursor CURSOR for SELECT ST_AsGeoJSON(geom) FROM vector_dat...
                                                             ^

Questions: Why did this ogr2ogr behavior change, and precisely where (which GitHub issue/PR)?

Answer 1

If the change was due to that commit https://github.com/OSGeo/gdal/pull/2405 then obviously it did not break anything that is tested. The PostGIS Python tests are in https://github.com/OSGeo/gdal/blob/master/autotest/ogr/ogr_pg.py. I guess that the code that handles the schema options is in https://github.com/OSGeo/gdal/blob/master/ogr/ogrsf_frmts/pg/ogrpgdatasource.cpp. Unfortunately I cannot read the code well enough to understand what it does for the search_path.

You can check what search_path GDAL gets by with ogrinfo. For me it shows:

ogrinfo PG:"host=localhost port=5432 user=username password=password" -sql "show search_path"
...
OGRFeature(sql_statement):1
  search_path (String) = "$user", public

It is possible to set the search_path with the -prelude_statements open option. For example

ogrinfo PG:"host=localhost port=5432 user=username password=password" -sql "show search_path"  -oo prelude_statements="SET search_path TO public,lidar"
...
OGRFeature(sql_statement):1
  search_path (String) = public, lidar

This way I query the data from a table that exists in the lidar schema, but not in "public" with

ogrinfo PG:"host=localhost port=5432 user=username -sql "select count(*) from test_dem2" -oo prelude_statements="SET search_path TO public,lidar"
...
OGRFeature(sql_statement):0
  count (Integer64) = 2