Database.Cassandra.Pool

Documentation

type CPool = Pool Cassandra Server

A round-robin pool of cassandra connections

type Server = (HostName, PortID)

defServer :: Server

A localhost server with default configuration

defServers :: [Server]

A single localhost server with default configuration

type KeySpace = String

data Cassandra

Constructors

Cassandra

Fields

cHandle :: Handle

cFramed :: FramedTransport Handle

cProto :: BinaryProtocol (FramedTransport Handle)

createCassandraPool

Arguments

:: [Server]

List of servers to connect to

-> Int

Max connections per server (n)

-> NominalDiffTime

Kill each connection after this many seconds

-> KeySpace

Each pool operates on a single KeySpace

-> IO CPool

Create a pool of connections to a cluster of Cassandra boxes

Each box in the cluster will get up to n connections. The pool will send queries in round-robin fashion to balance load on each box in the cluster.

newtype Pool a s

Constructors

Pool

Fields

stripes :: TVar (Ring (Stripe a s))

withPool :: Pool a s -> (a -> IO b) -> IO b

data Ring a

Constructors

Ring

Fields

current :: !a

used :: [a]

upcoming :: [a]

next :: Ring a -> Ring a

data Stripe a s

Constructors

Stripe

Fields

idle :: TVar [Connection a]

FIFO buffer of idle connections

inUse :: TVar Int

Set of in-use connections

server :: s

Server this strip is connected to

create :: s -> IO a

Create action

destroy :: a -> IO ()

Destroy action

cxns :: Int

Max connections

ttl :: NominalDiffTime

TTL for each connection

createStripe :: (s -> IO a) -> (a -> IO ()) -> Int -> NominalDiffTime -> s -> IO (Stripe a s)

withStripe :: Stripe a s -> (a -> IO b) -> IO b

data Connection a

Constructors

Connection

Fields

cxn :: a

lastUse :: UTCTime

modifyTVar_ :: TVar a -> (a -> a) -> STM ()

modError :: String -> String -> a