From c623c65fda619ac3fc0c4e34d13e969a64a7bb36 Mon Sep 17 00:00:00 2001
From: forest <forest.n.johnson@gmail.com>
Date: Tue, 23 Mar 2021 15:58:40 -0500
Subject: [PATCH] Limit the utilization of serializable transactions

A user encountered this error when deleting a vm:

self.cursor.execute("UPDATE vms SET deleted = now() WHERE email = %s AND
id = %s", ( email, id))

psycopg2.errors.SerializationFailure: could not serialize access due to
read/write dependencies among transactions
---
 capsulflask/db_model.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/capsulflask/db_model.py b/capsulflask/db_model.py
index 46101da..be44d30 100644
--- a/capsulflask/db_model.py
+++ b/capsulflask/db_model.py
@@ -13,7 +13,7 @@ class DBModel:
   def __init__(self, connection, cursor):
     self.connection = connection
     self.cursor = cursor
-    self.cursor.execute("SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;")
+
 
 
   #     ------    LOGIN     ---------     
@@ -361,6 +361,7 @@ class DBModel:
   def claim_operation(self, operation_id: int, host_id: str) -> bool:
     # have to make a new cursor to set isolation level
     # cursor = self.connection.cursor()
+    self.cursor.execute("SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;")
     self.cursor.execute("""
       BEGIN TRANSACTION;
       UPDATE host_operation SET assignment_status = 'assigned'