Safe Haskell	Safe-Inferred
Language	Haskell2010

Database.PostgreSQL.PQTypes.Internal.Connection

Contents

Connection
Running queries

Synopsis

newtype Connection = Connection {
- unConnection :: MVar (Maybe ConnectionData)
}
getBackendPidIO :: Connection -> IO BackendPid
data ConnectionData = ConnectionData {
- cdPtr :: !(Ptr PGconn)
- cdBackendPid :: !BackendPid
- cdStats :: !ConnectionStats
- cdPreparedQueries :: !(IORef (Set Text))
}
withConnectionData :: Connection -> String -> (ConnectionData -> IO (ConnectionData, r)) -> IO r
data ConnectionStats = ConnectionStats {
- statsQueries :: !Int
- statsRows :: !Int
- statsValues :: !Int
- statsParams :: !Int
}
data ConnectionSettings = ConnectionSettings {
- csConnInfo :: !Text
- csClientEncoding :: !(Maybe Text)
- csRole :: !(Maybe (RawSQL ()))
- csComposites :: ![Text]
}
defaultConnectionSettings :: ConnectionSettings
newtype ConnectionSourceM m = ConnectionSourceM {
- withConnection :: forall r. (Connection -> m r) -> m r
}
newtype ConnectionSource (cs :: [(Type -> Type) -> Constraint]) = ConnectionSource {
- unConnectionSource :: forall m. MkConstraint m cs => ConnectionSourceM m
}
simpleSource :: ConnectionSettings -> ConnectionSource [MonadBase IO, MonadMask]
poolSource :: ConnectionSettings -> (IO Connection -> (Connection -> IO ()) -> PoolConfig Connection) -> IO (ConnectionSource [MonadBase IO, MonadMask])
connect :: ConnectionSettings -> IO Connection
disconnect :: Connection -> IO ()
runQueryIO :: (HasCallStack, IsSQL sql) => Connection -> sql -> IO (Int, ForeignPtr PGresult)
newtype QueryName = QueryName Text
runPreparedQueryIO :: (HasCallStack, IsSQL sql) => Connection -> QueryName -> sql -> IO (Int, ForeignPtr PGresult)

Connection

newtype Connection Source #

Wrapper for hiding representation of a connection object.

Constructors

Connection
Fields unConnection :: MVar (Maybe ConnectionData)

getBackendPidIO :: Connection -> IO BackendPid Source #

data ConnectionData Source #

Representation of a connection object.

Note: PGconn is not managed with a ForeignPtr because finalizers are broken and at program exit might run even though another thread is inside the relevant withForeignPtr block, executing a safe FFI call (in this case executing an SQL query).

See https://gitlab.haskell.org/ghc/ghc/-/issues/10975 for more info.

Constructors

ConnectionData
Fields cdPtr :: !(Ptr PGconn) Pointer to connection object. cdBackendPid :: !BackendPid Process ID of the server process attached to the current session. cdStats :: !ConnectionStats Statistics associated with the connection. cdPreparedQueries :: !(IORef (Set Text)) A set of named prepared statements of the connection.

withConnectionData :: Connection -> String -> (ConnectionData -> IO (ConnectionData, r)) -> IO r Source #

data ConnectionStats Source #

Simple connection statistics.

Constructors

ConnectionStats
Fields statsQueries :: !Int Number of queries executed so far. statsRows :: !Int Number of rows fetched from the database. statsValues :: !Int Number of values fetched from the database. statsParams :: !Int Number of parameters sent to the database.

Instances

Instances details

Show ConnectionStats Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods showsPrec :: Int -> ConnectionStats -> ShowS # show :: ConnectionStats -> String # showList :: [ConnectionStats] -> ShowS #
Eq ConnectionStats Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods (==) :: ConnectionStats -> ConnectionStats -> Bool # (/=) :: ConnectionStats -> ConnectionStats -> Bool #
Ord ConnectionStats Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods compare :: ConnectionStats -> ConnectionStats -> Ordering # (<) :: ConnectionStats -> ConnectionStats -> Bool # (<=) :: ConnectionStats -> ConnectionStats -> Bool # (>) :: ConnectionStats -> ConnectionStats -> Bool # (>=) :: ConnectionStats -> ConnectionStats -> Bool # max :: ConnectionStats -> ConnectionStats -> ConnectionStats # min :: ConnectionStats -> ConnectionStats -> ConnectionStats #

data ConnectionSettings Source #

Constructors

ConnectionSettings
Fields csConnInfo :: !Text Connection info string. csClientEncoding :: !(Maybe Text) Client-side encoding. If set to `Nothing`, database encoding is used. csRole :: !(Maybe (RawSQL ())) A custom role to set with "SET ROLE". csComposites :: ![Text] A list of composite types to register. In order to be able to (de)serialize specific composite types, you need to register them.

Instances

Instances details

Show ConnectionSettings Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods showsPrec :: Int -> ConnectionSettings -> ShowS # show :: ConnectionSettings -> String # showList :: [ConnectionSettings] -> ShowS #
Eq ConnectionSettings Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods (==) :: ConnectionSettings -> ConnectionSettings -> Bool # (/=) :: ConnectionSettings -> ConnectionSettings -> Bool #
Ord ConnectionSettings Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods compare :: ConnectionSettings -> ConnectionSettings -> Ordering # (<) :: ConnectionSettings -> ConnectionSettings -> Bool # (<=) :: ConnectionSettings -> ConnectionSettings -> Bool # (>) :: ConnectionSettings -> ConnectionSettings -> Bool # (>=) :: ConnectionSettings -> ConnectionSettings -> Bool # max :: ConnectionSettings -> ConnectionSettings -> ConnectionSettings # min :: ConnectionSettings -> ConnectionSettings -> ConnectionSettings #

defaultConnectionSettings :: ConnectionSettings Source #

Default connection settings. Note that all strings sent to PostgreSQL by the library are encoded as UTF-8, so don't alter client encoding unless you know what you're doing.

newtype ConnectionSourceM m Source #

Database connection supplier.

Constructors

ConnectionSourceM
Fields withConnection :: forall r. (Connection -> m r) -> m r

newtype ConnectionSource (cs :: [(Type -> Type) -> Constraint]) Source #

Wrapper for a polymorphic connection source.

Constructors

ConnectionSource
Fields unConnectionSource :: forall m. MkConstraint m cs => ConnectionSourceM m

simpleSource :: ConnectionSettings -> ConnectionSource [MonadBase IO, MonadMask] Source #

Default connection supplier. It establishes new database connection each time withConnection is called.

poolSource Source #

Arguments

:: ConnectionSettings

-> (IO Connection -> (Connection -> IO ()) -> PoolConfig Connection)

A function for creating the PoolConfig with desired parameters.

Note: supplied arguments are for creation and destruction of a database connection.

-> IO (ConnectionSource [MonadBase IO, MonadMask])

Pooled source. It uses striped pool from resource-pool package to cache established connections and reuse them.

connect :: ConnectionSettings -> IO Connection Source #

Low-level function for connecting to the database. Useful if one wants to implement custom connection source.

Warning: the Connection needs to be explicitly destroyed with disconnect, otherwise there will be a resource leak.

disconnect :: Connection -> IO () Source #

Low-level function for disconnecting from the database. Useful if one wants to implement custom connection source.

Running queries

runQueryIO :: (HasCallStack, IsSQL sql) => Connection -> sql -> IO (Int, ForeignPtr PGresult) Source #

Low-level function for running an SQL query.

newtype QueryName Source #

Name of a prepared query.

Constructors

QueryName Text

Instances

Instances details

IsString QueryName Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods fromString :: String -> QueryName #
Show QueryName Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods showsPrec :: Int -> QueryName -> ShowS # show :: QueryName -> String # showList :: [QueryName] -> ShowS #
Eq QueryName Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods (==) :: QueryName -> QueryName -> Bool # (/=) :: QueryName -> QueryName -> Bool #
Ord QueryName Source #
Instance details Defined in Database.PostgreSQL.PQTypes.Internal.Connection Methods compare :: QueryName -> QueryName -> Ordering # (<) :: QueryName -> QueryName -> Bool # (<=) :: QueryName -> QueryName -> Bool # (>) :: QueryName -> QueryName -> Bool # (>=) :: QueryName -> QueryName -> Bool # max :: QueryName -> QueryName -> QueryName # min :: QueryName -> QueryName -> QueryName #

runPreparedQueryIO :: (HasCallStack, IsSQL sql) => Connection -> QueryName -> sql -> IO (Int, ForeignPtr PGresult) Source #

Low-level function for running a prepared SQL query.