Copyright	(c) James King 2020 2021
License	BSD3
Maintainer	[email protected]
Stability	experimental
Portability	POSIX
Safe Haskell	None
Language	Haskell2010

Database.PostgreSQL.Replicant.Protocol

Description

This module implements the Postgres streaming replication protocol.

See: https://www.postgresql.org/docs/9.5/protocol-replication.html

Synopsis

data IdentifySystem = IdentifySystem {
}
identifySystemCommand :: ByteString
identifySystemSync :: ReplicantConnection -> IO (Maybe IdentifySystem)
startReplicationCommand :: ReplicantConnection -> ByteString -> LSN -> IO ByteString
handleCopyOutData :: TChan PrimaryKeepAlive -> WalProgressState -> ReplicantConnection -> (Change -> IO LSN) -> IO ()
handleReplicationRow :: TChan PrimaryKeepAlive -> WalProgressState -> ReplicantConnection -> ByteString -> (Change -> IO LSN) -> IO ()
handleReplicationError :: ReplicantConnection -> IO ()
handleReplicationNoop :: IO ()
startReplicationStream :: ReplicantConnection -> ByteString -> LSN -> Int -> (Change -> IO LSN) -> IO ()
keepAliveHandler :: ReplicantConnection -> TChan PrimaryKeepAlive -> WalProgressState -> IO ()
sendStatusUpdate :: ReplicantConnection -> WalProgressState -> IO ()

Documentation

data IdentifySystem Source #

The information returned by the IDENTIFY_SYSTEM command establishes the stream's log start, position, and information about the database.

Constructors

IdentifySystem
Fields identifySystemSytemId :: ByteString identifySystemTimeline :: ByteString identifySystemLogPos :: LSN identifySystemDbName :: Maybe ByteString

Instances

Instances details

Eq IdentifySystem Source #
Instance details Defined in Database.PostgreSQL.Replicant.Protocol Methods (==) :: IdentifySystem -> IdentifySystem -> Bool # (/=) :: IdentifySystem -> IdentifySystem -> Bool #
Show IdentifySystem Source #
Instance details Defined in Database.PostgreSQL.Replicant.Protocol Methods showsPrec :: Int -> IdentifySystem -> ShowS # show :: IdentifySystem -> String # showList :: [IdentifySystem] -> ShowS #

identifySystemCommand :: ByteString Source #

identifySystemSync :: ReplicantConnection -> IO (Maybe IdentifySystem) Source #

Synchronously execute the IDENTIFY SYSTEM command which returns some basic system information about the server.

startReplicationCommand :: ReplicantConnection -> ByteString -> LSN -> IO ByteString Source #

Create a START_REPLICATION_SLOT query, escaping the slot name passed in by the user.

handleCopyOutData :: TChan PrimaryKeepAlive -> WalProgressState -> ReplicantConnection -> (Change -> IO LSN) -> IO () Source #

This handles the COPY OUT mode messages. PostgreSQL uses this mode to copy the data from a WAL log file to the socket in the streaming replication protocol.

handleReplicationRow :: TChan PrimaryKeepAlive -> WalProgressState -> ReplicantConnection -> ByteString -> (Change -> IO LSN) -> IO () Source #

handleReplicationError :: ReplicantConnection -> IO () Source #

Used to re-throw an exception received from the server.

handleReplicationNoop :: IO () Source #

startReplicationStream :: ReplicantConnection -> ByteString -> LSN -> Int -> (Change -> IO LSN) -> IO () Source #

Initiate the streaming replication protocol handler. This will race the keep-alive and copy data handler threads. It will catch and rethrow exceptions from either thread if any fails or returns.

keepAliveHandler :: ReplicantConnection -> TChan PrimaryKeepAlive -> WalProgressState -> IO () Source #

This listens on the channel for primary keep-alive messages from the server and responds to them with the update status message using the current WAL stream state. It will attempt to buffer prior update messages when the socket is blocked.

sendStatusUpdate :: ReplicantConnection -> WalProgressState -> IO () Source #