Hasql.Pool

Documentation

data Pool

A pool of connections to DB.

type Settings = (Int, Int, Settings)

Settings of the connection pool. Consist of:

• Pool-size.
• Timeout. An amount of time in milliseconds for which the unused connections are kept open.
• Connection settings.

acquire :: Settings -> IO Pool

Given the pool-size, timeout and connection settings create a connection-pool.

release :: Pool -> IO ()

Release the connection-pool.

data UsageError

A union over the connection establishment error and the session error.

Constructors

ConnectionUsageError ConnectionError

Error during an attempt to connect.

SessionUsageError QueryError

Error during session execution.

PoolIsReleasedUsageError

Pool has been released and can no longer be used.

Instances

Show UsageError

Defined in Hasql.Pool

Methods

showsPrec :: Int -> UsageError -> ShowS

show :: UsageError -> String

showList :: [UsageError] -> ShowS

Eq UsageError

Defined in Hasql.Pool

Methods

(==) :: UsageError -> UsageError -> Bool

(/=) :: UsageError -> UsageError -> Bool

use :: Pool -> Session a -> IO (Either UsageError a)

Use a connection from the pool to run a session and return the connection to the pool, when finished. If the session fails with ClientError the connection gets reestablished.