Database.PostgreSQL.PQTypes.Transaction.Settings

Documentation

data RestartPredicate

Predicate that determines whether the transaction has to be restarted.

Constructors

forall e . Exception e => RestartPredicate (e -> Integer -> Bool)

Instances

Show RestartPredicate

data TransactionSettings

Constructors

TransactionSettings

Fields

tsAutoTransaction :: !Bool

If set to True, transaction will be automatically started at the beginning of database action and after each commit / rollback. If set to False, no transaction will automatically start in either of above cases.

tsIsolationLevel :: !IsolationLevel

Isolation level of all transactions.

tsRestartPredicate :: !(Maybe RestartPredicate)

Defines behavior of withTransaction in case exceptions thrown within supplied monadic action are not caught and reach its body. If set to Nothing, exceptions will be propagated as usual. If set to Just f, exceptions will be intercepted and passed to f along with a number that indicates how many times the transaction block already failed. If f returns True, the transaction is restarted. Otherwise the exception is further propagated. This allows for restarting transactions e.g. in case of serialization failure. It is up to the caller to ensure that is it safe to execute supplied monadic action multiple times.

tsPermissions :: !Permissions

Permissions of all transactions.

Instances

Show TransactionSettings

Default TransactionSettings

Default transaction settings.

data IsolationLevel

Constructors

DefaultLevel

ReadCommitted

RepeatableRead

Serializable

Instances

Eq IsolationLevel

Ord IsolationLevel

Show IsolationLevel

data Permissions

Constructors

DefaultPermissions

ReadOnly

ReadWrite

Instances

Eq Permissions

Ord Permissions

Show Permissions

def :: Default a => a

The default value for this type.