just an intermediate state

openslides_backend/action/action_handler.py

@@ -5,7 +5,7 @@
 
 import fastjsonschema
 
-from openslides_backend.database.db_connection_handling import get_current_os_conn
+from openslides_backend.database.db_connection_handling import get_new_os_conn
 
 from ..shared.exceptions import (
     ActionException,
@@ -105,7 +105,7 @@ def handle_request(
         parsing all actions. In the end it sends everything to the event store.
         """
         with make_span(self.env, "handle request"):
-            with get_current_os_conn() as db_connection:
+            with get_new_os_conn() as db_connection:
                 self.db_connection = db_connection
                 self.user_id = user_id
                 self.internal = internal

openslides_backend/database/db_connection_handling.py

@@ -4,13 +4,15 @@
 
 import psycopg
 import psycopg_pool
-
 from openslides_backend.shared.env import Environment
 from openslides_backend.shared.exceptions import DatabaseException
 
 env = Environment(os.environ)
 conn_string_without_db = f"host='{env.DATABASE_HOST}' port='{env.DATABASE_PORT}' user='{env.DATABASE_USER}' password='{env.PGPASSWORD}' "
 
+def configure_connection(conn: psycopg.Connection) -> None:
+    """ callback, will be called after creation of new connection from connection pool"""
+    conn.isolation_level = psycopg.IsolationLevel.SERIALIZABLE
 
 def create_os_conn_pool(open: bool = True) -> psycopg_pool.ConnectionPool:
     """create the global connection pool on the openslides-db"""
@@ -32,6 +34,7 @@ def create_os_conn_pool(open: bool = True) -> psycopg_pool.ConnectionPool:
         max_idle=float(env.DB_POOL_MAX_IDLE),
         reconnect_timeout=float(env.DB_POOL_RECONNECT_TIMEOUT),
         num_workers=int(env.DB_POOL_NUM_WORKERS),
+        configure= configure_connection,
     )
     return os_conn_pool
 
@@ -50,7 +53,7 @@ def get_current_os_conn_pool() -> psycopg_pool.ConnectionPool:
     return os_conn_pool
 
 
-def get_current_os_conn() -> contextlib._GeneratorContextManager[psycopg.Connection]:
+def get_new_os_conn() -> contextlib._GeneratorContextManager[psycopg.Connection]:
     os_conn_pool = get_current_os_conn_pool()
     return os_conn_pool.connection()