| Type: | enum | 
| Default: | read committed | 
| Context: | user | 
| Restart: | false | 
| Values: | [serializable, repeatable read, read committed, read uncommitted] | 
| Since: | 9.6 | 
This parameter reflects the current transaction's isolation level. At the beginning of each transaction, it is set to the current value of default_transaction_isolation. Any subsequent attempt to change it is equivalent to a sql-set-transaction command.
Recommendations
                  Set per session if you need, for example, SERIALIZABLE semantics to prevent data conflicts for multi-step transactions.                
                
                
              