Random order when doing limit

pygeoapi_plugins/provider/mvt_postgresql.py

@@ -44,7 +44,7 @@
     ST_Transform,
 )
 
-from sqlalchemy.sql import select
+from sqlalchemy.sql import select, func
 from sqlalchemy.orm import Session
 from pygeofilter.parsers.ecql import parse as parse_ecql_text
 
@@ -295,7 +295,7 @@ def _get_mvt_cte(self, envelope, envelope_srid, z):
 
         # Apply tile limit if set
         if self.tile_limit:
-            query = query.limit(self.tile_limit)
+            query = query.order_by(func.random()).limit(self.tile_limit)
 
         # Return as CTE
         return query.cte('mvtcte').table_valued()

tests/test_mvt_postgresql_provider.py

@@ -158,7 +158,7 @@ def test_tile_limit(config):
         y=y,
     )
     assert tile is not None
-    assert len(tile) == pytest.approx(74047, 0.1)
+    assert len(tile) == pytest.approx(74047, 0.5)
 
     config['tile_limit'] = 1000
     p = MVTPostgreSQLProvider_(config)
@@ -169,7 +169,7 @@ def test_tile_limit(config):
         y=y,
     )
     assert tile2 is not None
-    assert len(tile2) == pytest.approx(74047, 0.1)
+    assert len(tile2) == pytest.approx(74047, 0.5)
     assert len(tile2) <= len(tile)
 
     config['tile_limit'] = 500
@@ -181,7 +181,7 @@ def test_tile_limit(config):
         y=y,
     )
     assert tile3 is not None
-    assert len(tile3) == pytest.approx(59142, 0.1)
+    assert len(tile3) == pytest.approx(59142, 0.5)
     assert len(tile3) < len(tile)
     assert len(tile3) < len(tile2)
 
@@ -194,7 +194,7 @@ def test_tile_limit(config):
         y=y,
     )
     assert tile4 is not None
-    assert len(tile4) == pytest.approx(18408, 0.1)
+    assert len(tile4) == pytest.approx(18408, 1)
     assert len(tile4) < len(tile)
     assert len(tile4) < len(tile2)
     assert len(tile4) < len(tile3)