Use raw SQL query for get_subjects_intersection()

src/tribler/core/components/knowledge/db/knowledge_db.py

@@ -5,6 +5,7 @@
 from typing import Callable, Iterator, List, Optional, Set
 
 from pony import orm
+from pony.orm import raw_sql
 from pony.orm.core import Entity, Query, select
 from pony.utils import between
 
@@ -358,39 +359,30 @@ def get_suggestions(self, subject_type: Optional[ResourceType] = None, subject:
     def get_subjects_intersection(self, subjects_type: Optional[ResourceType], objects: Set[str],
                                   predicate: Optional[ResourceType],
                                   case_sensitive: bool = True) -> Set[str]:
-        """Queries the subjects with the given objects and the predicate. Then made an intersection among them.
+        if not objects:
+            return set()
 
-        In the Tribler, this method is mostly used for searching by tags.
-
-        Args:
-            subjects_type: a type of subjects.
-            objects: a set of strings that represents the objects.
-            predicate: the enum that represents a predicate of querying operations.
-            case_sensitive: if True, then Resources are selected in a case-sensitive manner. if False, then Resources
-                are selected in a case-insensitive manner.
-
-        Returns: a list of the strings representing the subjects.
-        """
         if case_sensitive:
-            def name_condition(obj, obj_name):
-                return obj.name == obj_name
+            name_condition = '"obj"."name" = $obj_name'
         else:
-            def name_condition(obj, obj_name):
-                return obj.name.lower() == obj_name.lower()
-
-        query = select(subject.name for subject in self.instance.Resource if subject.type == subjects_type.value)
-        for object_name in objects:
-            query = query.where(lambda subject: subject in (
-                s.subject for s in self.instance.Statement
-                if (s.local_operation == Operation.ADD.value
-                    or not s.local_operation
-                    and s.score >= SHOW_THRESHOLD
-                    and s.object in (
-                        obj for obj in self.instance.Resource
-                        if (obj.type == predicate.value
-                            and name_condition(obj, object_name))
-                    ))
-            ))
+            name_condition = 'py_lower("obj"."name") = py_lower($obj_name)'
+
+        query = select(r.name for r in self.instance.Resource)
+        for obj_name in objects:
+            query = query.filter(raw_sql(f"""
+    r.id IN (
+        SELECT "s"."subject"
+        FROM "Statement" "s"
+        WHERE (
+            "s"."local_operation" = $(Operation.ADD.value)
+        OR
+            ("s"."local_operation" = 0 OR "s"."local_operation" IS NULL)
+            AND ("s"."added_count" - "s"."removed_count") >= $SHOW_THRESHOLD
+        ) AND "s"."object" IN (
+            SELECT "obj"."id" FROM "Resource" "obj"
+            WHERE "obj"."type" = $(predicate.value) AND {name_condition}
+        )
+    )"""))
         return set(query)
 
     def get_clock(self, operation: StatementOperation) -> int: