org.apache.ratis.server.raftlog.segmented

Class SegmentedRaftLog

java.lang.Object

org.apache.ratis.server.raftlog.RaftLogBase

org.apache.ratis.server.raftlog.segmented.SegmentedRaftLog

All Implemented Interfaces:

Closeable, AutoCloseable, RaftLog

public final class SegmentedRaftLog
extends RaftLogBase

The RaftLog implementation that writes log entries into segmented files in local disk. The max log segment size is 8MB. The real log segment size may not be exactly equal to this limit. If a log entry's size exceeds 8MB, this entry will be stored in a single segment. There are two types of segments: closed segment and open segment. The former is named as "log_startindex-endindex", the later is named as "log_inprogress_startindex". There can be multiple closed segments but there is at most one open segment. When the open segment reaches the size limit, or the log term increases, we close the open segment and start a new open segment. A closed segment cannot be appended anymore, but it can be truncated in case that a follower's log is inconsistent with the current leader. Every closed segment should be non-empty, i.e., it should contain at least one entry. There should not be any gap between segments. The first segment may not start from index 0 since there may be snapshots as log compaction. The last index in segments should be no smaller than the last index of snapshot, otherwise we may have hole when append further log.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RaftLogSequentialOps.Runner
static class	SegmentedRaftLog.Builder

Nested classes/interfaces inherited from interface org.apache.ratis.server.raftlog.RaftLog

RaftLog.EntryWithData

Field Summary

Fields inherited from class org.apache.ratis.server.raftlog.RaftLogBase

INVALID_LOG_INDEX, LEAST_VALID_LOG_INDEX

Fields inherited from interface org.apache.ratis.server.raftlog.RaftLog

LOG

Method Summary

Modifier and Type	Method and Description
default List<CompletableFuture<Long>>	append(org.apache.ratis.proto.RaftProtos.LogEntryProto... arg0) Deprecated.
protected CompletableFuture<Long>	appendEntryImpl(org.apache.ratis.proto.RaftProtos.LogEntryProto entry, TransactionContext context)
List<CompletableFuture<Long>>	appendImpl(List<org.apache.ratis.proto.RaftProtos.LogEntryProto> entries)
void	close()
org.apache.ratis.proto.RaftProtos.LogEntryProto	get(long index)
LogEntryHeader[]	getEntries(long startIndex, long endIndex)
RaftLog.EntryWithData	getEntryWithData(long index)
long	getFlushIndex()
TermIndex	getLastEntryTermIndex()
SegmentedRaftLogMetrics	getRaftLogMetrics()
long	getStartIndex()
TermIndex	getTermIndex(long index)
RaftStorageMetadata	loadMetadata()
static SegmentedRaftLog.Builder	newBuilder()
CompletableFuture<Long>	onSnapshotInstalled(long lastSnapshotIndex)
protected void	openImpl(long lastIndexInSnapshot, Consumer<org.apache.ratis.proto.RaftProtos.LogEntryProto> consumer)
void	persistMetadata(RaftStorageMetadata metadata)
protected CompletableFuture<Long>	purgeImpl(long index)
String	toLogEntryString(org.apache.ratis.proto.RaftProtos.LogEntryProto logEntry)
protected CompletableFuture<Long>	truncateImpl(long index)

Methods inherited from class org.apache.ratis.server.raftlog.RaftLogBase

append, append, append, appendEntry, appendEntry, appendMetadata, checkLogState, getLastCommittedIndex, getName, getSnapshotIndex, hasReadLock, hasWriteLock, isOpened, newEntryWithData, open, purge, readLock, toString, truncate, updateCommitIndex, updateSnapshotIndex, updateSnapshotIndexFromStateMachine, validateLogEntry, writeLock

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.ratis.server.raftlog.RaftLog

contains, getNextIndex

Method Detail

getRaftLogMetrics

public SegmentedRaftLogMetrics getRaftLogMetrics()

openImpl

protected void openImpl(long lastIndexInSnapshot,
                        Consumer<org.apache.ratis.proto.RaftProtos.LogEntryProto> consumer)
                 throws IOException

Overrides:

openImpl in class RaftLogBase

Throws:

IOException

getStartIndex

public long getStartIndex()

get

public org.apache.ratis.proto.RaftProtos.LogEntryProto get(long index)
                                                    throws RaftLogIOException

Throws:

RaftLogIOException

getEntryWithData

public RaftLog.EntryWithData getEntryWithData(long index)
                                       throws RaftLogIOException

Throws:

RaftLogIOException

getTermIndex

public TermIndex getTermIndex(long index)

getEntries

public LogEntryHeader[] getEntries(long startIndex,
                                   long endIndex)

getLastEntryTermIndex

public TermIndex getLastEntryTermIndex()

truncateImpl

protected CompletableFuture<Long> truncateImpl(long index)

Specified by:

truncateImpl in class RaftLogBase

purgeImpl

protected CompletableFuture<Long> purgeImpl(long index)

Specified by:

purgeImpl in class RaftLogBase

appendEntryImpl

protected CompletableFuture<Long> appendEntryImpl(org.apache.ratis.proto.RaftProtos.LogEntryProto entry,
                                                  TransactionContext context)

Specified by:

appendEntryImpl in class RaftLogBase

appendImpl

public List<CompletableFuture<Long>> appendImpl(List<org.apache.ratis.proto.RaftProtos.LogEntryProto> entries)

Specified by:

appendImpl in class RaftLogBase

getFlushIndex

public long getFlushIndex()

persistMetadata

public void persistMetadata(RaftStorageMetadata metadata)
                     throws IOException

Throws:

IOException

loadMetadata

public RaftStorageMetadata loadMetadata()
                                 throws IOException

Throws:

IOException

onSnapshotInstalled

public CompletableFuture<Long> onSnapshotInstalled(long lastSnapshotIndex)

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Overrides:

close in class RaftLogBase

Throws:

IOException

toLogEntryString

public String toLogEntryString(org.apache.ratis.proto.RaftProtos.LogEntryProto logEntry)

Overrides:

toLogEntryString in class RaftLogBase

newBuilder

public static SegmentedRaftLog.Builder newBuilder()

append

@Deprecated
public List<CompletableFuture<Long>> append(org.apache.ratis.proto.RaftProtos.LogEntryProto... arg0)

Deprecated.