{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DuplicateRecordFields #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
{-# LANGUAGE StrictData #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# OPTIONS_GHC -fno-warn-unused-imports #-}
{-# OPTIONS_GHC -fno-warn-unused-matches #-}

-- Derived from AWS service descriptions, licensed under Apache 2.0.

-- |
-- Module      : Amazonka.RDS.Types.DBClusterBacktrack
-- Copyright   : (c) 2013-2021 Brendan Hay
-- License     : Mozilla Public License, v. 2.0.
-- Maintainer  : Brendan Hay <brendan.g.hay+amazonka@gmail.com>
-- Stability   : auto-generated
-- Portability : non-portable (GHC extensions)
module Amazonka.RDS.Types.DBClusterBacktrack where

import qualified Amazonka.Core as Core
import qualified Amazonka.Lens as Lens
import qualified Amazonka.Prelude as Prelude

-- | This data type is used as a response element in the
-- @DescribeDBClusterBacktracks@ action.
--
-- /See:/ 'newDBClusterBacktrack' smart constructor.
data DBClusterBacktrack = DBClusterBacktrack'
  { -- | The status of the backtrack. This property returns one of the following
    -- values:
    --
    -- -   @applying@ - The backtrack is currently being applied to or rolled
    --     back from the DB cluster.
    --
    -- -   @completed@ - The backtrack has successfully been applied to or
    --     rolled back from the DB cluster.
    --
    -- -   @failed@ - An error occurred while the backtrack was applied to or
    --     rolled back from the DB cluster.
    --
    -- -   @pending@ - The backtrack is currently pending application to or
    --     rollback from the DB cluster.
    DBClusterBacktrack -> Maybe Text
status :: Prelude.Maybe Prelude.Text,
    -- | Contains the backtrack identifier.
    DBClusterBacktrack -> Maybe Text
backtrackIdentifier :: Prelude.Maybe Prelude.Text,
    -- | The timestamp of the time to which the DB cluster was backtracked.
    DBClusterBacktrack -> Maybe ISO8601
backtrackTo :: Prelude.Maybe Core.ISO8601,
    -- | Contains a user-supplied DB cluster identifier. This identifier is the
    -- unique key that identifies a DB cluster.
    DBClusterBacktrack -> Maybe Text
dbClusterIdentifier :: Prelude.Maybe Prelude.Text,
    -- | The timestamp of the time from which the DB cluster was backtracked.
    DBClusterBacktrack -> Maybe ISO8601
backtrackedFrom :: Prelude.Maybe Core.ISO8601,
    -- | The timestamp of the time at which the backtrack was requested.
    DBClusterBacktrack -> Maybe ISO8601
backtrackRequestCreationTime :: Prelude.Maybe Core.ISO8601
  }
  deriving (DBClusterBacktrack -> DBClusterBacktrack -> Bool
(DBClusterBacktrack -> DBClusterBacktrack -> Bool)
-> (DBClusterBacktrack -> DBClusterBacktrack -> Bool)
-> Eq DBClusterBacktrack
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: DBClusterBacktrack -> DBClusterBacktrack -> Bool
$c/= :: DBClusterBacktrack -> DBClusterBacktrack -> Bool
== :: DBClusterBacktrack -> DBClusterBacktrack -> Bool
$c== :: DBClusterBacktrack -> DBClusterBacktrack -> Bool
Prelude.Eq, ReadPrec [DBClusterBacktrack]
ReadPrec DBClusterBacktrack
Int -> ReadS DBClusterBacktrack
ReadS [DBClusterBacktrack]
(Int -> ReadS DBClusterBacktrack)
-> ReadS [DBClusterBacktrack]
-> ReadPrec DBClusterBacktrack
-> ReadPrec [DBClusterBacktrack]
-> Read DBClusterBacktrack
forall a.
(Int -> ReadS a)
-> ReadS [a] -> ReadPrec a -> ReadPrec [a] -> Read a
readListPrec :: ReadPrec [DBClusterBacktrack]
$creadListPrec :: ReadPrec [DBClusterBacktrack]
readPrec :: ReadPrec DBClusterBacktrack
$creadPrec :: ReadPrec DBClusterBacktrack
readList :: ReadS [DBClusterBacktrack]
$creadList :: ReadS [DBClusterBacktrack]
readsPrec :: Int -> ReadS DBClusterBacktrack
$creadsPrec :: Int -> ReadS DBClusterBacktrack
Prelude.Read, Int -> DBClusterBacktrack -> ShowS
[DBClusterBacktrack] -> ShowS
DBClusterBacktrack -> String
(Int -> DBClusterBacktrack -> ShowS)
-> (DBClusterBacktrack -> String)
-> ([DBClusterBacktrack] -> ShowS)
-> Show DBClusterBacktrack
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [DBClusterBacktrack] -> ShowS
$cshowList :: [DBClusterBacktrack] -> ShowS
show :: DBClusterBacktrack -> String
$cshow :: DBClusterBacktrack -> String
showsPrec :: Int -> DBClusterBacktrack -> ShowS
$cshowsPrec :: Int -> DBClusterBacktrack -> ShowS
Prelude.Show, (forall x. DBClusterBacktrack -> Rep DBClusterBacktrack x)
-> (forall x. Rep DBClusterBacktrack x -> DBClusterBacktrack)
-> Generic DBClusterBacktrack
forall x. Rep DBClusterBacktrack x -> DBClusterBacktrack
forall x. DBClusterBacktrack -> Rep DBClusterBacktrack x
forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
$cto :: forall x. Rep DBClusterBacktrack x -> DBClusterBacktrack
$cfrom :: forall x. DBClusterBacktrack -> Rep DBClusterBacktrack x
Prelude.Generic)

-- |
-- Create a value of 'DBClusterBacktrack' with all optional fields omitted.
--
-- Use <https://hackage.haskell.org/package/generic-lens generic-lens> or <https://hackage.haskell.org/package/optics optics> to modify other optional fields.
--
-- The following record fields are available, with the corresponding lenses provided
-- for backwards compatibility:
--
-- 'status', 'dbClusterBacktrack_status' - The status of the backtrack. This property returns one of the following
-- values:
--
-- -   @applying@ - The backtrack is currently being applied to or rolled
--     back from the DB cluster.
--
-- -   @completed@ - The backtrack has successfully been applied to or
--     rolled back from the DB cluster.
--
-- -   @failed@ - An error occurred while the backtrack was applied to or
--     rolled back from the DB cluster.
--
-- -   @pending@ - The backtrack is currently pending application to or
--     rollback from the DB cluster.
--
-- 'backtrackIdentifier', 'dbClusterBacktrack_backtrackIdentifier' - Contains the backtrack identifier.
--
-- 'backtrackTo', 'dbClusterBacktrack_backtrackTo' - The timestamp of the time to which the DB cluster was backtracked.
--
-- 'dbClusterIdentifier', 'dbClusterBacktrack_dbClusterIdentifier' - Contains a user-supplied DB cluster identifier. This identifier is the
-- unique key that identifies a DB cluster.
--
-- 'backtrackedFrom', 'dbClusterBacktrack_backtrackedFrom' - The timestamp of the time from which the DB cluster was backtracked.
--
-- 'backtrackRequestCreationTime', 'dbClusterBacktrack_backtrackRequestCreationTime' - The timestamp of the time at which the backtrack was requested.
newDBClusterBacktrack ::
  DBClusterBacktrack
newDBClusterBacktrack :: DBClusterBacktrack
newDBClusterBacktrack =
  DBClusterBacktrack' :: Maybe Text
-> Maybe Text
-> Maybe ISO8601
-> Maybe Text
-> Maybe ISO8601
-> Maybe ISO8601
-> DBClusterBacktrack
DBClusterBacktrack'
    { $sel:status:DBClusterBacktrack' :: Maybe Text
status = Maybe Text
forall a. Maybe a
Prelude.Nothing,
      $sel:backtrackIdentifier:DBClusterBacktrack' :: Maybe Text
backtrackIdentifier = Maybe Text
forall a. Maybe a
Prelude.Nothing,
      $sel:backtrackTo:DBClusterBacktrack' :: Maybe ISO8601
backtrackTo = Maybe ISO8601
forall a. Maybe a
Prelude.Nothing,
      $sel:dbClusterIdentifier:DBClusterBacktrack' :: Maybe Text
dbClusterIdentifier = Maybe Text
forall a. Maybe a
Prelude.Nothing,
      $sel:backtrackedFrom:DBClusterBacktrack' :: Maybe ISO8601
backtrackedFrom = Maybe ISO8601
forall a. Maybe a
Prelude.Nothing,
      $sel:backtrackRequestCreationTime:DBClusterBacktrack' :: Maybe ISO8601
backtrackRequestCreationTime = Maybe ISO8601
forall a. Maybe a
Prelude.Nothing
    }

-- | The status of the backtrack. This property returns one of the following
-- values:
--
-- -   @applying@ - The backtrack is currently being applied to or rolled
--     back from the DB cluster.
--
-- -   @completed@ - The backtrack has successfully been applied to or
--     rolled back from the DB cluster.
--
-- -   @failed@ - An error occurred while the backtrack was applied to or
--     rolled back from the DB cluster.
--
-- -   @pending@ - The backtrack is currently pending application to or
--     rollback from the DB cluster.
dbClusterBacktrack_status :: Lens.Lens' DBClusterBacktrack (Prelude.Maybe Prelude.Text)
dbClusterBacktrack_status :: (Maybe Text -> f (Maybe Text))
-> DBClusterBacktrack -> f DBClusterBacktrack
dbClusterBacktrack_status = (DBClusterBacktrack -> Maybe Text)
-> (DBClusterBacktrack -> Maybe Text -> DBClusterBacktrack)
-> Lens
     DBClusterBacktrack DBClusterBacktrack (Maybe Text) (Maybe Text)
forall s a b t. (s -> a) -> (s -> b -> t) -> Lens s t a b
Lens.lens (\DBClusterBacktrack' {Maybe Text
status :: Maybe Text
$sel:status:DBClusterBacktrack' :: DBClusterBacktrack -> Maybe Text
status} -> Maybe Text
status) (\s :: DBClusterBacktrack
s@DBClusterBacktrack' {} Maybe Text
a -> DBClusterBacktrack
s {$sel:status:DBClusterBacktrack' :: Maybe Text
status = Maybe Text
a} :: DBClusterBacktrack)

-- | Contains the backtrack identifier.
dbClusterBacktrack_backtrackIdentifier :: Lens.Lens' DBClusterBacktrack (Prelude.Maybe Prelude.Text)
dbClusterBacktrack_backtrackIdentifier :: (Maybe Text -> f (Maybe Text))
-> DBClusterBacktrack -> f DBClusterBacktrack
dbClusterBacktrack_backtrackIdentifier = (DBClusterBacktrack -> Maybe Text)
-> (DBClusterBacktrack -> Maybe Text -> DBClusterBacktrack)
-> Lens
     DBClusterBacktrack DBClusterBacktrack (Maybe Text) (Maybe Text)
forall s a b t. (s -> a) -> (s -> b -> t) -> Lens s t a b
Lens.lens (\DBClusterBacktrack' {Maybe Text
backtrackIdentifier :: Maybe Text
$sel:backtrackIdentifier:DBClusterBacktrack' :: DBClusterBacktrack -> Maybe Text
backtrackIdentifier} -> Maybe Text
backtrackIdentifier) (\s :: DBClusterBacktrack
s@DBClusterBacktrack' {} Maybe Text
a -> DBClusterBacktrack
s {$sel:backtrackIdentifier:DBClusterBacktrack' :: Maybe Text
backtrackIdentifier = Maybe Text
a} :: DBClusterBacktrack)

-- | The timestamp of the time to which the DB cluster was backtracked.
dbClusterBacktrack_backtrackTo :: Lens.Lens' DBClusterBacktrack (Prelude.Maybe Prelude.UTCTime)
dbClusterBacktrack_backtrackTo :: (Maybe UTCTime -> f (Maybe UTCTime))
-> DBClusterBacktrack -> f DBClusterBacktrack
dbClusterBacktrack_backtrackTo = (DBClusterBacktrack -> Maybe ISO8601)
-> (DBClusterBacktrack -> Maybe ISO8601 -> DBClusterBacktrack)
-> Lens
     DBClusterBacktrack
     DBClusterBacktrack
     (Maybe ISO8601)
     (Maybe ISO8601)
forall s a b t. (s -> a) -> (s -> b -> t) -> Lens s t a b
Lens.lens (\DBClusterBacktrack' {Maybe ISO8601
backtrackTo :: Maybe ISO8601
$sel:backtrackTo:DBClusterBacktrack' :: DBClusterBacktrack -> Maybe ISO8601
backtrackTo} -> Maybe ISO8601
backtrackTo) (\s :: DBClusterBacktrack
s@DBClusterBacktrack' {} Maybe ISO8601
a -> DBClusterBacktrack
s {$sel:backtrackTo:DBClusterBacktrack' :: Maybe ISO8601
backtrackTo = Maybe ISO8601
a} :: DBClusterBacktrack) ((Maybe ISO8601 -> f (Maybe ISO8601))
 -> DBClusterBacktrack -> f DBClusterBacktrack)
-> ((Maybe UTCTime -> f (Maybe UTCTime))
    -> Maybe ISO8601 -> f (Maybe ISO8601))
-> (Maybe UTCTime -> f (Maybe UTCTime))
-> DBClusterBacktrack
-> f DBClusterBacktrack
forall b c a. (b -> c) -> (a -> b) -> a -> c
Prelude.. AnIso ISO8601 ISO8601 UTCTime UTCTime
-> Iso
     (Maybe ISO8601) (Maybe ISO8601) (Maybe UTCTime) (Maybe UTCTime)
forall (f :: * -> *) (g :: * -> *) s t a b.
(Functor f, Functor g) =>
AnIso s t a b -> Iso (f s) (g t) (f a) (g b)
Lens.mapping AnIso ISO8601 ISO8601 UTCTime UTCTime
forall (a :: Format). Iso' (Time a) UTCTime
Core._Time

-- | Contains a user-supplied DB cluster identifier. This identifier is the
-- unique key that identifies a DB cluster.
dbClusterBacktrack_dbClusterIdentifier :: Lens.Lens' DBClusterBacktrack (Prelude.Maybe Prelude.Text)
dbClusterBacktrack_dbClusterIdentifier :: (Maybe Text -> f (Maybe Text))
-> DBClusterBacktrack -> f DBClusterBacktrack
dbClusterBacktrack_dbClusterIdentifier = (DBClusterBacktrack -> Maybe Text)
-> (DBClusterBacktrack -> Maybe Text -> DBClusterBacktrack)
-> Lens
     DBClusterBacktrack DBClusterBacktrack (Maybe Text) (Maybe Text)
forall s a b t. (s -> a) -> (s -> b -> t) -> Lens s t a b
Lens.lens (\DBClusterBacktrack' {Maybe Text
dbClusterIdentifier :: Maybe Text
$sel:dbClusterIdentifier:DBClusterBacktrack' :: DBClusterBacktrack -> Maybe Text
dbClusterIdentifier} -> Maybe Text
dbClusterIdentifier) (\s :: DBClusterBacktrack
s@DBClusterBacktrack' {} Maybe Text
a -> DBClusterBacktrack
s {$sel:dbClusterIdentifier:DBClusterBacktrack' :: Maybe Text
dbClusterIdentifier = Maybe Text
a} :: DBClusterBacktrack)

-- | The timestamp of the time from which the DB cluster was backtracked.
dbClusterBacktrack_backtrackedFrom :: Lens.Lens' DBClusterBacktrack (Prelude.Maybe Prelude.UTCTime)
dbClusterBacktrack_backtrackedFrom :: (Maybe UTCTime -> f (Maybe UTCTime))
-> DBClusterBacktrack -> f DBClusterBacktrack
dbClusterBacktrack_backtrackedFrom = (DBClusterBacktrack -> Maybe ISO8601)
-> (DBClusterBacktrack -> Maybe ISO8601 -> DBClusterBacktrack)
-> Lens
     DBClusterBacktrack
     DBClusterBacktrack
     (Maybe ISO8601)
     (Maybe ISO8601)
forall s a b t. (s -> a) -> (s -> b -> t) -> Lens s t a b
Lens.lens (\DBClusterBacktrack' {Maybe ISO8601
backtrackedFrom :: Maybe ISO8601
$sel:backtrackedFrom:DBClusterBacktrack' :: DBClusterBacktrack -> Maybe ISO8601
backtrackedFrom} -> Maybe ISO8601
backtrackedFrom) (\s :: DBClusterBacktrack
s@DBClusterBacktrack' {} Maybe ISO8601
a -> DBClusterBacktrack
s {$sel:backtrackedFrom:DBClusterBacktrack' :: Maybe ISO8601
backtrackedFrom = Maybe ISO8601
a} :: DBClusterBacktrack) ((Maybe ISO8601 -> f (Maybe ISO8601))
 -> DBClusterBacktrack -> f DBClusterBacktrack)
-> ((Maybe UTCTime -> f (Maybe UTCTime))
    -> Maybe ISO8601 -> f (Maybe ISO8601))
-> (Maybe UTCTime -> f (Maybe UTCTime))
-> DBClusterBacktrack
-> f DBClusterBacktrack
forall b c a. (b -> c) -> (a -> b) -> a -> c
Prelude.. AnIso ISO8601 ISO8601 UTCTime UTCTime
-> Iso
     (Maybe ISO8601) (Maybe ISO8601) (Maybe UTCTime) (Maybe UTCTime)
forall (f :: * -> *) (g :: * -> *) s t a b.
(Functor f, Functor g) =>
AnIso s t a b -> Iso (f s) (g t) (f a) (g b)
Lens.mapping AnIso ISO8601 ISO8601 UTCTime UTCTime
forall (a :: Format). Iso' (Time a) UTCTime
Core._Time

-- | The timestamp of the time at which the backtrack was requested.
dbClusterBacktrack_backtrackRequestCreationTime :: Lens.Lens' DBClusterBacktrack (Prelude.Maybe Prelude.UTCTime)
dbClusterBacktrack_backtrackRequestCreationTime :: (Maybe UTCTime -> f (Maybe UTCTime))
-> DBClusterBacktrack -> f DBClusterBacktrack
dbClusterBacktrack_backtrackRequestCreationTime = (DBClusterBacktrack -> Maybe ISO8601)
-> (DBClusterBacktrack -> Maybe ISO8601 -> DBClusterBacktrack)
-> Lens
     DBClusterBacktrack
     DBClusterBacktrack
     (Maybe ISO8601)
     (Maybe ISO8601)
forall s a b t. (s -> a) -> (s -> b -> t) -> Lens s t a b
Lens.lens (\DBClusterBacktrack' {Maybe ISO8601
backtrackRequestCreationTime :: Maybe ISO8601
$sel:backtrackRequestCreationTime:DBClusterBacktrack' :: DBClusterBacktrack -> Maybe ISO8601
backtrackRequestCreationTime} -> Maybe ISO8601
backtrackRequestCreationTime) (\s :: DBClusterBacktrack
s@DBClusterBacktrack' {} Maybe ISO8601
a -> DBClusterBacktrack
s {$sel:backtrackRequestCreationTime:DBClusterBacktrack' :: Maybe ISO8601
backtrackRequestCreationTime = Maybe ISO8601
a} :: DBClusterBacktrack) ((Maybe ISO8601 -> f (Maybe ISO8601))
 -> DBClusterBacktrack -> f DBClusterBacktrack)
-> ((Maybe UTCTime -> f (Maybe UTCTime))
    -> Maybe ISO8601 -> f (Maybe ISO8601))
-> (Maybe UTCTime -> f (Maybe UTCTime))
-> DBClusterBacktrack
-> f DBClusterBacktrack
forall b c a. (b -> c) -> (a -> b) -> a -> c
Prelude.. AnIso ISO8601 ISO8601 UTCTime UTCTime
-> Iso
     (Maybe ISO8601) (Maybe ISO8601) (Maybe UTCTime) (Maybe UTCTime)
forall (f :: * -> *) (g :: * -> *) s t a b.
(Functor f, Functor g) =>
AnIso s t a b -> Iso (f s) (g t) (f a) (g b)
Lens.mapping AnIso ISO8601 ISO8601 UTCTime UTCTime
forall (a :: Format). Iso' (Time a) UTCTime
Core._Time

instance Core.FromXML DBClusterBacktrack where
  parseXML :: [Node] -> Either String DBClusterBacktrack
parseXML [Node]
x =
    Maybe Text
-> Maybe Text
-> Maybe ISO8601
-> Maybe Text
-> Maybe ISO8601
-> Maybe ISO8601
-> DBClusterBacktrack
DBClusterBacktrack'
      (Maybe Text
 -> Maybe Text
 -> Maybe ISO8601
 -> Maybe Text
 -> Maybe ISO8601
 -> Maybe ISO8601
 -> DBClusterBacktrack)
-> Either String (Maybe Text)
-> Either
     String
     (Maybe Text
      -> Maybe ISO8601
      -> Maybe Text
      -> Maybe ISO8601
      -> Maybe ISO8601
      -> DBClusterBacktrack)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
Prelude.<$> ([Node]
x [Node] -> Text -> Either String (Maybe Text)
forall a. FromXML a => [Node] -> Text -> Either String (Maybe a)
Core..@? Text
"Status")
      Either
  String
  (Maybe Text
   -> Maybe ISO8601
   -> Maybe Text
   -> Maybe ISO8601
   -> Maybe ISO8601
   -> DBClusterBacktrack)
-> Either String (Maybe Text)
-> Either
     String
     (Maybe ISO8601
      -> Maybe Text
      -> Maybe ISO8601
      -> Maybe ISO8601
      -> DBClusterBacktrack)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
Prelude.<*> ([Node]
x [Node] -> Text -> Either String (Maybe Text)
forall a. FromXML a => [Node] -> Text -> Either String (Maybe a)
Core..@? Text
"BacktrackIdentifier")
      Either
  String
  (Maybe ISO8601
   -> Maybe Text
   -> Maybe ISO8601
   -> Maybe ISO8601
   -> DBClusterBacktrack)
-> Either String (Maybe ISO8601)
-> Either
     String
     (Maybe Text
      -> Maybe ISO8601 -> Maybe ISO8601 -> DBClusterBacktrack)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
Prelude.<*> ([Node]
x [Node] -> Text -> Either String (Maybe ISO8601)
forall a. FromXML a => [Node] -> Text -> Either String (Maybe a)
Core..@? Text
"BacktrackTo")
      Either
  String
  (Maybe Text
   -> Maybe ISO8601 -> Maybe ISO8601 -> DBClusterBacktrack)
-> Either String (Maybe Text)
-> Either
     String (Maybe ISO8601 -> Maybe ISO8601 -> DBClusterBacktrack)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
Prelude.<*> ([Node]
x [Node] -> Text -> Either String (Maybe Text)
forall a. FromXML a => [Node] -> Text -> Either String (Maybe a)
Core..@? Text
"DBClusterIdentifier")
      Either
  String (Maybe ISO8601 -> Maybe ISO8601 -> DBClusterBacktrack)
-> Either String (Maybe ISO8601)
-> Either String (Maybe ISO8601 -> DBClusterBacktrack)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
Prelude.<*> ([Node]
x [Node] -> Text -> Either String (Maybe ISO8601)
forall a. FromXML a => [Node] -> Text -> Either String (Maybe a)
Core..@? Text
"BacktrackedFrom")
      Either String (Maybe ISO8601 -> DBClusterBacktrack)
-> Either String (Maybe ISO8601)
-> Either String DBClusterBacktrack
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
Prelude.<*> ([Node]
x [Node] -> Text -> Either String (Maybe ISO8601)
forall a. FromXML a => [Node] -> Text -> Either String (Maybe a)
Core..@? Text
"BacktrackRequestCreationTime")

instance Prelude.Hashable DBClusterBacktrack

instance Prelude.NFData DBClusterBacktrack