Optimize get_items() (#447)

benchmarks/get_parameter_value_items.py

@@ -0,0 +1,59 @@
+"""
+This benchmark tests the performance of getting a list of parameter value items from database mapping.
+"""
+
+import pathlib
+from tempfile import TemporaryDirectory
+import time
+import pyperf
+from spinedb_api import DatabaseMapping, to_database
+from spinedb_api.mapped_items import EntityItem, ParameterDefinitionItem
+
+
+def get_value_items(
+    loops: int, db_map: DatabaseMapping, entity_item: EntityItem, parameter_definition_item: ParameterDefinitionItem
+) -> float:
+    duration = 0.0
+    for _ in range(loops):
+        start = time.perf_counter()
+        values = db_map.get_parameter_value_items(
+            entity_class_name=entity_item["entity_class_name"],
+            entity_byname=entity_item["entity_byname"],
+            parameter_definition_name=parameter_definition_item["name"],
+        )
+        duration += time.perf_counter() - start
+        assert len(values) == 1
+    return duration
+
+
+def run_benchmark(file_name: str) -> None:
+    runner = pyperf.Runner()
+    with TemporaryDirectory() as temp_dir:
+        db_path = pathlib.Path(temp_dir) / "db.sqlite"
+        url = "sqlite:///" + str(db_path)
+        with DatabaseMapping(url, create=True) as db_map:
+            db_map.add_entity_class_item(name="Widget")
+            db_map.add_entity_item(name="spoon", entity_class_name="Widget")
+            db_map.add_parameter_definition_item(name="weight", entity_class_name="Widget")
+            value, value_type = to_database(2.3)
+            db_map.add_parameter_value_item(
+                entity_class_name="Widget",
+                entity_byname=("spoon",),
+                parameter_definition_name="weight",
+                alternative_name="Base",
+                value=value,
+                type=value_type,
+            )
+            db_map.commit_session("Add data")
+        with DatabaseMapping(url) as db_map:
+            entity_item = db_map.get_entity_item(name="spoon", entity_class_name="Widget")
+            parameter_definition_item = db_map.get_parameter_definition_item(name="weight", entity_class_name="Widget")
+            benchmark = runner.bench_time_func(
+                "get value items", get_value_items, db_map, entity_item, parameter_definition_item
+            )
+        if file_name and benchmark is not None:
+            pyperf.add_runs(file_name, benchmark)
+
+
+if __name__ == "__main__":
+    run_benchmark("")