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.


Set per session if you need, for example, SERIALIZABLE semantics to prevent data conflicts for multi-step transactions.