org.apache.hadoop.hdfs.qjournal.protocol

Interface QJournalProtocol

All Known Implementing Classes:

QJournalProtocolTranslatorPB

@InterfaceAudience.Private
public interface QJournalProtocol

Protocol used to communicate between QuorumJournalManager and each JournalNode. This is responsible for sending edits as well as coordinating recovery of the nodes.

Field Summary

Fields

Modifier and Type	Field and Description
static long	versionID

Method Summary

Methods

Modifier and Type	Method and Description
void	acceptRecovery(RequestInfo reqInfo, QJournalProtocolProtos.SegmentStateProto stateToAccept, URL fromUrl) Accept a proposed recovery for the given transaction ID.
void	finalizeLogSegment(RequestInfo reqInfo, long startTxId, long endTxId) Finalize the given log segment on the JournalNode.
void	format(String journalId, NamespaceInfo nsInfo) Format the underlying storage for the given namespace.
QJournalProtocolProtos.GetEditLogManifestResponseProto	getEditLogManifest(String jid, long sinceTxId, boolean forReading, boolean inProgressOk)
QJournalProtocolProtos.GetJournalStateResponseProto	getJournalState(String journalId) Get the current state of the journal, including the most recent epoch number and the HTTP port.
void	heartbeat(RequestInfo reqInfo) Heartbeat.
boolean	isFormatted(String journalId)
void	journal(RequestInfo reqInfo, long segmentTxId, long firstTxnId, int numTxns, byte[] records) Journal edit records.
QJournalProtocolProtos.NewEpochResponseProto	newEpoch(String journalId, NamespaceInfo nsInfo, long epoch) Begin a new epoch.
QJournalProtocolProtos.PrepareRecoveryResponseProto	prepareRecovery(RequestInfo reqInfo, long segmentTxId) Begin the recovery process for a given segment.
void	purgeLogsOlderThan(RequestInfo requestInfo, long minTxIdToKeep)
void	startLogSegment(RequestInfo reqInfo, long txid) Start writing to a new log segment on the JournalNode.

Field Detail

versionID

static final long versionID

See Also:

Constant Field Values

Method Detail

isFormatted

boolean isFormatted(String journalId)
                    throws IOException

Returns:

true if the given journal has been formatted and contains valid data.

Throws:

IOException

getJournalState

QJournalProtocolProtos.GetJournalStateResponseProto getJournalState(String journalId)
                                                                    throws IOException

Get the current state of the journal, including the most recent epoch number and the HTTP port.

Throws:

IOException

format

void format(String journalId,
          NamespaceInfo nsInfo)
            throws IOException

Format the underlying storage for the given namespace.

Throws:

IOException

newEpoch

QJournalProtocolProtos.NewEpochResponseProto newEpoch(String journalId,
                                                    NamespaceInfo nsInfo,
                                                    long epoch)
                                                      throws IOException

Begin a new epoch. See the HDFS-3077 design doc for details.

Throws:

IOException

journal

void journal(RequestInfo reqInfo,
           long segmentTxId,
           long firstTxnId,
           int numTxns,
           byte[] records)
             throws IOException

Journal edit records. This message is sent by the active name-node to the JournalNodes to write edits to their local logs.

Throws:

IOException

heartbeat

void heartbeat(RequestInfo reqInfo)
               throws IOException

Heartbeat. This is a no-op on the server, except that it verifies that the caller is in fact still the active writer, and provides up-to-date information on the most recently committed txid.

Throws:

IOException

startLogSegment

void startLogSegment(RequestInfo reqInfo,
                   long txid)
                     throws IOException

Start writing to a new log segment on the JournalNode. Before calling this, one should finalize the previous segment using finalizeLogSegment(RequestInfo, long, long).

Parameters:

txid - the first txid in the new log

Throws:

IOException

finalizeLogSegment

void finalizeLogSegment(RequestInfo reqInfo,
                      long startTxId,
                      long endTxId)
                        throws IOException

Finalize the given log segment on the JournalNode. The segment is expected to be in-progress and starting at the given startTxId.

Parameters:

startTxId - the starting transaction ID of the log

endTxId - the expected last transaction in the given log

Throws:

IOException - if no such segment exists

purgeLogsOlderThan

void purgeLogsOlderThan(RequestInfo requestInfo,
                      long minTxIdToKeep)
                        throws IOException

Throws:

IOException

See Also:

LogsPurgeable.purgeLogsOlderThan(long)

getEditLogManifest

QJournalProtocolProtos.GetEditLogManifestResponseProto getEditLogManifest(String jid,
                                                                        long sinceTxId,
                                                                        boolean forReading,
                                                                        boolean inProgressOk)
                                                                          throws IOException

Parameters:

jid - the journal from which to enumerate edits

sinceTxId - the first transaction which the client cares about

forReading - whether or not the caller intends to read from the edit logs

inProgressOk - whether or not to check the in-progress edit log segment

Returns:

a list of edit log segments since the given transaction ID.

Throws:

IOException

prepareRecovery

QJournalProtocolProtos.PrepareRecoveryResponseProto prepareRecovery(RequestInfo reqInfo,
                                                                  long segmentTxId)
                                                                    throws IOException

Begin the recovery process for a given segment. See the HDFS-3077 design document for details.

Throws:

IOException

acceptRecovery

void acceptRecovery(RequestInfo reqInfo,
                  QJournalProtocolProtos.SegmentStateProto stateToAccept,
                  URL fromUrl)
                    throws IOException

Accept a proposed recovery for the given transaction ID.

Throws:

IOException