Inline simple_search_list/simple_search_list_txn. (#16434)

This only has a single use and is over abstracted. Inline it so that
we can improve type hints.

changelog.d/16434.misc

@@ -0,0 +1 @@
+Reduce memory allocations.

synapse/rest/admin/users.py

@@ -842,7 +842,18 @@ class SearchUsersRestServlet(RestServlet):
         logger.info("term: %s ", term)
 
         ret = await self.store.search_users(term)
-        return HTTPStatus.OK, ret
+        results = [
+            {
+                "name": name,
+                "password_hash": password_hash,
+                "is_guest": bool(is_guest),
+                "admin": bool(admin),
+                "user_type": user_type,
+            }
+            for name, password_hash, is_guest, admin, user_type in ret
+        ]
+
+        return HTTPStatus.OK, results
 
 
 class UserAdminServlet(RestServlet):

synapse/storage/database.py

@@ -2476,68 +2476,6 @@ class DatabasePool:
 
         return txn.fetchall()
 
-    async def simple_search_list(
-        self,
-        table: str,
-        term: Optional[str],
-        col: str,
-        retcols: Collection[str],
-        desc: str = "simple_search_list",
-    ) -> Optional[List[Dict[str, Any]]]:
-        """Executes a SELECT query on the named table, which may return zero or
-        more rows, returning the result as a list of dicts.
-
-        Args:
-            table: the table name
-            term: term for searching the table matched to a column.
-            col: column to query term should be matched to
-            retcols: the names of the columns to return
-
-        Returns:
-            A list of dictionaries or None.
-        """
-
-        return await self.runInteraction(
-            desc,
-            self.simple_search_list_txn,
-            table,
-            term,
-            col,
-            retcols,
-            db_autocommit=True,
-        )
-
-    @classmethod
-    def simple_search_list_txn(
-        cls,
-        txn: LoggingTransaction,
-        table: str,
-        term: Optional[str],
-        col: str,
-        retcols: Iterable[str],
-    ) -> Optional[List[Dict[str, Any]]]:
-        """Executes a SELECT query on the named table, which may return zero or
-        more rows, returning the result as a list of dicts.
-
-        Args:
-            txn: Transaction object
-            table: the table name
-            term: term for searching the table matched to a column.
-            col: column to query term should be matched to
-            retcols: the names of the columns to return
-
-        Returns:
-            None if no term is given, otherwise a list of dictionaries.
-        """
-        if term:
-            sql = "SELECT %s FROM %s WHERE %s LIKE ?" % (", ".join(retcols), table, col)
-            termvalues = ["%%" + term + "%%"]
-            txn.execute(sql, termvalues)
-        else:
-            return None
-
-        return cls.cursor_to_dict(txn)
-
 
 def make_in_list_sql_clause(
     database_engine: BaseDatabaseEngine, column: str, iterable: Collection[Any]

synapse/storage/databases/main/__init__.py

@@ -15,7 +15,7 @@
 # limitations under the License.
 
 import logging
-from typing import TYPE_CHECKING, List, Optional, Tuple, cast
+from typing import TYPE_CHECKING, List, Optional, Tuple, Union, cast
 
 from synapse.api.constants import Direction
 from synapse.config.homeserver import HomeServerConfig
@@ -296,7 +296,11 @@ class DataStore(
             "get_users_paginate_txn", get_users_paginate_txn
         )
 
-    async def search_users(self, term: str) -> Optional[List[JsonDict]]:
+    async def search_users(
+        self, term: str
+    ) -> List[
+        Tuple[str, Optional[str], Union[int, bool], Union[int, bool], Optional[str]]
+    ]:
         """Function to search users list for one or more users with
         the matched term.
 
@@ -304,16 +308,38 @@ class DataStore(
             term: search term
 
         Returns:
-            A list of dictionaries or None.
+            A list of tuples of name, password_hash, is_guest, admin, user_type or None.
         """
-        return await self.db_pool.simple_search_list(
-            table="users",
-            term=term,
-            col="name",
-            retcols=["name", "password_hash", "is_guest", "admin", "user_type"],
-            desc="search_users",
+
+        def search_users(
+            txn: LoggingTransaction,
+        ) -> List[
+            Tuple[str, Optional[str], Union[int, bool], Union[int, bool], Optional[str]]
+        ]:
+            search_term = "%%" + term + "%%"
+
+            sql = """
+            SELECT name, password_hash, is_guest, admin, user_type
+            FROM users
+            WHERE name LIKE ?
+            """
+            txn.execute(sql, (search_term,))
+
+            return cast(
+                List[
+                    Tuple[
+                        str,
+                        Optional[str],
+                        Union[int, bool],
+                        Union[int, bool],
+                        Optional[str],
+                    ]
+                ],
+                txn.fetchall(),
             )
 
+        return await self.db_pool.runInteraction("search_users", search_users)
+
 
 def check_database_before_upgrade(
     cur: Cursor, database_engine: BaseDatabaseEngine, config: HomeServerConfig