org.corfudb.infrastructure

Class LogUnitServer

java.lang.Object

org.corfudb.infrastructure.AbstractServer

org.corfudb.infrastructure.LogUnitServer

public class LogUnitServer
extends AbstractServer

Created by mwei on 12/10/15.

A Log Unit Server, which is responsible for providing the persistent storage for the Corfu Distributed Shared Log.

All reads and writes go through a cache. For persistence, every 10,000 log entries are written to individual files (logs), which are represented as FileHandles. Each FileHandle contains a pointer to the tail of the file, a memory-mapped file channel, and a set of addresses known to be in the file. To append an entry, the pointer to the tail is first extended to the length of the entry, and the entry is added to the set of known addresses. A header is written, which consists of the ASCII characters LE, followed by a set of flags, the log unit address, the size of the entry, then the metadata size, metadata and finally the entry itself . When the entry is complete, a written flag is set in the flags field.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LogUnitServer.LogUnitServerConfig Log unit server configuration class

Nested classes/interfaces inherited from class org.corfudb.infrastructure.AbstractServer

AbstractServer.ServerState

Constructor Summary

Constructors

Constructor and Description
LogUnitServer(ServerContext serverContext) Returns a new LogUnitServer.

Method Summary

Modifier and Type	Method and Description
com.github.benmanes.caffeine.cache.LoadingCache<Long,ILogData>	getDataCache()
ExecutorService	getExecutor()
void	handleLogAddressSpaceRequest(CorfuMsg msg, io.netty.channel.ChannelHandlerContext ctx, IServerRouter r) Service an incoming request for log address space, i.e., the map of addresses for every stream in the log.
void	handleTailRequest(CorfuPayloadMsg<TailsRequest> msg, io.netty.channel.ChannelHandlerContext ctx, IServerRouter r) Service an incoming request for maximum global address the log unit server has written.
void	handleTrimMarkRequest(CorfuMsg msg, io.netty.channel.ChannelHandlerContext ctx, IServerRouter r) Service an incoming request to retrieve the starting address of this logging unit.
boolean	isServerReadyToHandleMsg(CorfuMsg msg)
void	rangeWrite(CorfuPayloadMsg<RangeWriteMsg> msg, io.netty.channel.ChannelHandlerContext ctx, IServerRouter r) Services incoming range write calls.
void	sealServerWithEpoch(long epoch) Seal the server with the epoch.
void	shutdown() Shutdown the server.
void	write(CorfuPayloadMsg<WriteRequest> msg, io.netty.channel.ChannelHandlerContext ctx, IServerRouter r) Service an incoming write request.

Methods inherited from class org.corfudb.infrastructure.AbstractServer

getHandler, getState, handleMessage, setState

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

LogUnitServer

public LogUnitServer(ServerContext serverContext)

Returns a new LogUnitServer.

Parameters:

serverContext - context object providing settings and objects

Method Detail

getExecutor

public ExecutorService getExecutor()

Specified by:

getExecutor in class AbstractServer

handleTailRequest

public void handleTailRequest(CorfuPayloadMsg<TailsRequest> msg,
                              io.netty.channel.ChannelHandlerContext ctx,
                              IServerRouter r)

Service an incoming request for maximum global address the log unit server has written.

handleLogAddressSpaceRequest

public void handleLogAddressSpaceRequest(CorfuMsg msg,
                                         io.netty.channel.ChannelHandlerContext ctx,
                                         IServerRouter r)

Service an incoming request for log address space, i.e., the map of addresses for every stream in the log. This is used on sequencer bootstrap to provide the address maps for initialization.

handleTrimMarkRequest

public void handleTrimMarkRequest(CorfuMsg msg,
                                  io.netty.channel.ChannelHandlerContext ctx,
                                  IServerRouter r)

Service an incoming request to retrieve the starting address of this logging unit.

write

public void write(CorfuPayloadMsg<WriteRequest> msg,
                  io.netty.channel.ChannelHandlerContext ctx,
                  IServerRouter r)

Service an incoming write request.

rangeWrite

public void rangeWrite(CorfuPayloadMsg<RangeWriteMsg> msg,
                       io.netty.channel.ChannelHandlerContext ctx,
                       IServerRouter r)

Services incoming range write calls.

sealServerWithEpoch

public void sealServerWithEpoch(long epoch)

Seal the server with the epoch.

- A seal operation is inserted in the queue and then we wait to flush all operations in the queue before this operation. - All operations after this operation but stamped with an older epoch will be failed.

Overrides:

sealServerWithEpoch in class AbstractServer

Parameters:

epoch - Epoch to seal with

isServerReadyToHandleMsg

public boolean isServerReadyToHandleMsg(CorfuMsg msg)

Specified by:

isServerReadyToHandleMsg in class AbstractServer

shutdown

public void shutdown()

Shutdown the server.

Overrides:

shutdown in class AbstractServer

getDataCache

public com.github.benmanes.caffeine.cache.LoadingCache<Long,ILogData> getDataCache()