[db] Disable JIT for postgres (#12893)

* disable postgres JIT by default

* Update docs

docs/docs/start/config.md

@@ -280,6 +280,10 @@ If running with a PostgreSQL database backend, the following additional options
 | `INVENTREE_DB_TCP_KEEPALIVES_COUNT` | database.tcp_keepalives_count | 5 | TCP keepalive count |
 | `INVENTREE_DB_TCP_USER_TIMEOUT` | database.tcp_user_timeout | 2000 | TCP user timeout (ms) |
 | `INVENTREE_DB_ISOLATION_SERIALIZABLE` | database.serializable | False | Database isolation level configured to "serializable" |
+| `INVENTREE_DB_JIT_ENABLED` | database.jit_enabled | False | Enable JIT compilation for PostgreSQL queries |
+
+!!! info "JIT Compilation"
+    PostgreSQL supports [JIT compilation](https://www.postgresql.org/docs/current/jit.html) for queries. This is disabled by default, as it can cause performance issues for small queries.
 
 ### MySQL Settings
 

src/backend/InvenTree/InvenTree/setting/db_backend.py

@@ -208,6 +208,19 @@ def set_postgres_options(db_options: dict):
             'inventree-worker' if isInWorkerThread() else 'inventree-server'
         )
 
+    extra_options = []
+
+    if 'options' in db_options:
+        extra_options.append(db_options['options'])
+
+    if not get_boolean_setting(
+        'INVENTREE_DB_JIT_ENABLED', 'database.jit_enabled', False
+    ):
+        extra_options.append('-c jit=off')
+
+    if extra_options:
+        db_options['options'] = ' '.join(extra_options)
+
 
 def set_mysql_options(db_options: dict):
     """Set database options specific to mysql backend."""