import akka.japi.Procedure;
import akka.persistence.SnapshotSelectionCriteria;
-import com.google.protobuf.ByteString;
-import org.opendaylight.controller.cluster.DataPersistenceProvider;
+import com.google.common.annotations.VisibleForTesting;
+import java.util.List;
import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot;
import org.opendaylight.controller.cluster.raft.base.messages.SendInstallSnapshot;
import org.opendaylight.controller.cluster.raft.behaviors.RaftActorBehavior;
public class SnapshotManager implements SnapshotState {
-
private final SnapshotState IDLE = new Idle();
- private final SnapshotState CAPTURING = new Capturing();
private final SnapshotState PERSISTING = new Persisting();
private final SnapshotState CREATING = new Creating();
private SnapshotState currentState = IDLE;
private CaptureSnapshot captureSnapshot;
+ private long lastSequenceNumber = -1;
+
+ private Procedure<Void> createSnapshotProcedure;
+
+ private Snapshot applySnapshot;
+ private Procedure<byte[]> applySnapshotProcedure;
public SnapshotManager(RaftActorContext context, Logger logger) {
this.context = context;
}
@Override
- public void captureToInstall(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
- currentState.captureToInstall(lastLogEntry, replicatedToAllIndex);
+ public boolean captureToInstall(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex, String targetFollower) {
+ return currentState.captureToInstall(lastLogEntry, replicatedToAllIndex, targetFollower);
}
@Override
- public void capture(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
- currentState.capture(lastLogEntry, replicatedToAllIndex);
+ public boolean capture(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
+ return currentState.capture(lastLogEntry, replicatedToAllIndex);
}
@Override
- public void create(Procedure<Void> callback) {
- currentState.create(callback);
+ public void apply(Snapshot snapshot) {
+ currentState.apply(snapshot);
}
@Override
- public void persist(DataPersistenceProvider persistenceProvider, byte[] snapshotBytes, RaftActorBehavior currentBehavior) {
- currentState.persist(persistenceProvider, snapshotBytes, currentBehavior);
+ public void persist(byte[] snapshotBytes, RaftActorBehavior currentBehavior, long totalMemory) {
+ currentState.persist(snapshotBytes, currentBehavior, totalMemory);
}
@Override
- public void commit(DataPersistenceProvider persistenceProvider, long sequenceNumber) {
- currentState.commit(persistenceProvider, sequenceNumber);
+ public void commit(long sequenceNumber, RaftActorBehavior currentBehavior) {
+ currentState.commit(sequenceNumber, currentBehavior);
}
@Override
}
@Override
- public long trimLog(long desiredTrimIndex) {
- return currentState.trimLog(desiredTrimIndex);
+ public long trimLog(long desiredTrimIndex, RaftActorBehavior currentBehavior) {
+ return currentState.trimLog(desiredTrimIndex, currentBehavior);
+ }
+
+ public void setCreateSnapshotCallable(Procedure<Void> createSnapshotProcedure) {
+ this.createSnapshotProcedure = createSnapshotProcedure;
+ }
+
+ public void setApplySnapshotProcedure(Procedure<byte[]> applySnapshotProcedure) {
+ this.applySnapshotProcedure = applySnapshotProcedure;
+ }
+
+ public long getLastSequenceNumber() {
+ return lastSequenceNumber;
+ }
+
+ @VisibleForTesting
+ public CaptureSnapshot getCaptureSnapshot() {
+ return captureSnapshot;
}
private boolean hasFollowers(){
@Override
public boolean isCapturing() {
- return false;
+ return true;
}
@Override
- public void capture(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
+ public boolean capture(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
LOG.debug("capture should not be called in state {}", this);
+ return false;
}
@Override
- public void captureToInstall(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
+ public boolean captureToInstall(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex, String targetFollower) {
LOG.debug("captureToInstall should not be called in state {}", this);
+ return false;
}
@Override
- public void create(Procedure<Void> callback) {
- LOG.debug("create should not be called in state {}", this);
+ public void apply(Snapshot snapshot) {
+ LOG.debug("apply should not be called in state {}", this);
}
@Override
- public void persist(DataPersistenceProvider persistenceProvider, byte[] snapshotBytes, RaftActorBehavior currentBehavior) {
+ public void persist(byte[] snapshotBytes, RaftActorBehavior currentBehavior, long totalMemory) {
LOG.debug("persist should not be called in state {}", this);
}
@Override
- public void commit(DataPersistenceProvider persistenceProvider, long sequenceNumber) {
+ public void commit(long sequenceNumber, RaftActorBehavior currentBehavior) {
LOG.debug("commit should not be called in state {}", this);
}
}
@Override
- public long trimLog(long desiredTrimIndex) {
+ public long trimLog(long desiredTrimIndex, RaftActorBehavior currentBehavior) {
LOG.debug("trimLog should not be called in state {}", this);
return -1;
}
- protected long doTrimLog(long desiredTrimIndex){
+ protected long doTrimLog(long desiredTrimIndex, RaftActorBehavior currentBehavior){
// we would want to keep the lastApplied as its used while capturing snapshots
long lastApplied = context.getLastApplied();
long tempMin = Math.min(desiredTrimIndex, (lastApplied > -1 ? lastApplied - 1 : -1));
- if (tempMin > -1 && context.getReplicatedLog().isPresent(tempMin)) {
+ if(LOG.isTraceEnabled()) {
+ LOG.trace("{}: performSnapshotWithoutCapture: desiredTrimIndex: {}, lastApplied: {}, tempMin: {}",
+ persistenceId(), desiredTrimIndex, lastApplied, tempMin);
+ }
+
+ if (tempMin > -1 && context.getReplicatedLog().isPresent(tempMin)) {
LOG.debug("{}: fakeSnapshot purging log to {} for term {}", persistenceId(), tempMin,
context.getTermInformation().getCurrentTerm());
context.getReplicatedLog().snapshotPreCommit(tempMin, entry.getTerm());
context.getReplicatedLog().snapshotCommit();
return tempMin;
+ } else if(tempMin > currentBehavior.getReplicatedToAllIndex()) {
+ // It's possible a follower was lagging and an install snapshot advanced its match index past
+ // the current replicatedToAllIndex. Since the follower is now caught up we should advance the
+ // replicatedToAllIndex (to tempMin). The fact that tempMin wasn't found in the log is likely
+ // due to a previous snapshot triggered by the memory threshold exceeded, in that case we
+ // trim the log to the last applied index even if previous entries weren't replicated to all followers.
+ currentBehavior.setReplicatedToAllIndex(tempMin);
}
-
return -1;
}
}
private class Idle extends AbstractSnapshotState {
- private void capture(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex, boolean toInstall) {
+ @Override
+ public boolean isCapturing() {
+ return false;
+ }
+
+ private boolean capture(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex, String targetFollower) {
TermInformationReader lastAppliedTermInfoReader =
lastAppliedTermInformationReader.init(context.getReplicatedLog(), context.getLastApplied(),
lastLogEntry, hasFollowers());
long newReplicatedToAllTerm = replicatedToAllTermInfoReader.getTerm();
// send a CaptureSnapshot to self to make the expensive operation async.
- captureSnapshot = new CaptureSnapshot(lastLogEntry.getIndex(),
- lastLogEntry.getTerm(), lastAppliedIndex, lastAppliedTerm,
- newReplicatedToAllIndex, newReplicatedToAllTerm, toInstall);
- SnapshotManager.this.currentState = CAPTURING;
+ List<ReplicatedLogEntry> unAppliedEntries = context.getReplicatedLog().getFrom(lastAppliedIndex + 1);
- LOG.info("{}: Initiating snapshot capture {}: {}", persistenceId(), toInstall ? "to install" : "",
- captureSnapshot);
+ long lastLogEntryIndex = lastAppliedIndex;
+ long lastLogEntryTerm = lastAppliedTerm;
+ if(lastLogEntry != null) {
+ lastLogEntryIndex = lastLogEntry.getIndex();
+ lastLogEntryTerm = lastLogEntry.getTerm();
+ } else {
+ LOG.warn("Capturing Snapshot : lastLogEntry is null. Using lastAppliedIndex {} and lastAppliedTerm {} instead.",
+ lastAppliedIndex, lastAppliedTerm);
+ }
- context.getActor().tell(captureSnapshot, context.getActor());
- }
+ captureSnapshot = new CaptureSnapshot(lastLogEntryIndex,
+ lastLogEntryTerm, lastAppliedIndex, lastAppliedTerm,
+ newReplicatedToAllIndex, newReplicatedToAllTerm, unAppliedEntries, targetFollower != null);
- @Override
- public void capture(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
- capture(lastLogEntry, replicatedToAllIndex, false);
+ if(captureSnapshot.isInstallSnapshotInitiated()) {
+ LOG.info("{}: Initiating snapshot capture {} to install on {}",
+ persistenceId(), captureSnapshot, targetFollower);
+ } else {
+ LOG.info("{}: Initiating snapshot capture {}", persistenceId(), captureSnapshot);
+ }
+
+ lastSequenceNumber = context.getPersistenceProvider().getLastSequenceNumber();
+
+ LOG.debug("lastSequenceNumber prior to capture: {}", lastSequenceNumber);
+
+ SnapshotManager.this.currentState = CREATING;
+
+ try {
+ createSnapshotProcedure.apply(null);
+ } catch (Exception e) {
+ SnapshotManager.this.currentState = IDLE;
+ LOG.error("Error creating snapshot", e);
+ return false;
+ }
+
+ return true;
}
@Override
- public void captureToInstall(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
- capture(lastLogEntry, replicatedToAllIndex, true);
+ public boolean capture(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex) {
+ return capture(lastLogEntry, replicatedToAllIndex, null);
}
@Override
- public String toString() {
- return "Idle";
+ public boolean captureToInstall(ReplicatedLogEntry lastLogEntry, long replicatedToAllIndex, String targetFollower) {
+ return capture(lastLogEntry, replicatedToAllIndex, targetFollower);
}
@Override
- public long trimLog(long desiredTrimIndex) {
- return doTrimLog(desiredTrimIndex);
- }
- }
+ public void apply(Snapshot snapshot) {
+ applySnapshot = snapshot;
- private class Capturing extends AbstractSnapshotState {
+ lastSequenceNumber = context.getPersistenceProvider().getLastSequenceNumber();
- @Override
- public boolean isCapturing() {
- return true;
- }
+ LOG.debug("lastSequenceNumber prior to persisting applied snapshot: {}", lastSequenceNumber);
- @Override
- public void create(Procedure<Void> callback) {
- try {
- callback.apply(null);
- SnapshotManager.this.currentState = CREATING;
- } catch (Exception e) {
- LOG.error("Unexpected error occurred", e);
- }
+ context.getPersistenceProvider().saveSnapshot(snapshot);
+
+ SnapshotManager.this.currentState = PERSISTING;
}
@Override
public String toString() {
- return "Capturing";
+ return "Idle";
}
+ @Override
+ public long trimLog(long desiredTrimIndex, RaftActorBehavior currentBehavior) {
+ return doTrimLog(desiredTrimIndex, currentBehavior);
+ }
}
private class Creating extends AbstractSnapshotState {
@Override
- public boolean isCapturing() {
- return true;
- }
-
- @Override
- public void persist(DataPersistenceProvider persistenceProvider, byte[] snapshotBytes,
- RaftActorBehavior currentBehavior) {
+ public void persist(byte[] snapshotBytes, RaftActorBehavior currentBehavior, long totalMemory) {
// create a snapshot object from the state provided and save it
// when snapshot is saved async, SaveSnapshotSuccess is raised.
- Snapshot sn = Snapshot.create(snapshotBytes,
- context.getReplicatedLog().getFrom(captureSnapshot.getLastAppliedIndex() + 1),
+ Snapshot snapshot = Snapshot.create(snapshotBytes,
+ captureSnapshot.getUnAppliedEntries(),
captureSnapshot.getLastIndex(), captureSnapshot.getLastTerm(),
- captureSnapshot.getLastAppliedIndex(), captureSnapshot.getLastAppliedTerm());
+ captureSnapshot.getLastAppliedIndex(), captureSnapshot.getLastAppliedTerm(),
+ context.getTermInformation().getCurrentTerm(),
+ context.getTermInformation().getVotedFor());
- persistenceProvider.saveSnapshot(sn);
+ context.getPersistenceProvider().saveSnapshot(snapshot);
- LOG.info("{}: Persisting of snapshot done:{}", persistenceId(), sn.getLogMessage());
+ LOG.info("{}: Persisting of snapshot done: {}", persistenceId(), snapshot);
- long dataThreshold = Runtime.getRuntime().totalMemory() *
+ long dataThreshold = totalMemory *
context.getConfigParams().getSnapshotDataThresholdPercentage() / 100;
- if (context.getReplicatedLog().dataSize() > dataThreshold) {
- // if memory is less, clear the log based on lastApplied.
- // this could/should only happen if one of the followers is down
- // as normally we keep removing from the log when its replicated to all.
+ boolean dataSizeThresholdExceeded = context.getReplicatedLog().dataSize() > dataThreshold;
+
+ boolean logSizeExceededSnapshotBatchCount =
+ context.getReplicatedLog().size() >= context.getConfigParams().getSnapshotBatchCount();
+
+ if (dataSizeThresholdExceeded || logSizeExceededSnapshotBatchCount) {
+ if(LOG.isDebugEnabled()) {
+ if(dataSizeThresholdExceeded) {
+ LOG.debug("{}: log data size {} exceeds the memory threshold {} - doing snapshotPreCommit with index {}",
+ context.getId(), context.getReplicatedLog().dataSize(), dataThreshold,
+ captureSnapshot.getLastAppliedIndex());
+ } else {
+ LOG.debug("{}: log size {} exceeds the snapshot batch count {} - doing snapshotPreCommit with index {}",
+ context.getId(), context.getReplicatedLog().size(),
+ context.getConfigParams().getSnapshotBatchCount(), captureSnapshot.getLastAppliedIndex());
+ }
+ }
+
+ // We either exceeded the memory threshold or the log size exceeded the snapshot batch
+ // count so, to keep the log memory footprint in check, clear the log based on lastApplied.
+ // This could/should only happen if one of the followers is down as normally we keep
+ // removing from the log as entries are replicated to all.
context.getReplicatedLog().snapshotPreCommit(captureSnapshot.getLastAppliedIndex(),
captureSnapshot.getLastAppliedTerm());
- currentBehavior.setReplicatedToAllIndex(captureSnapshot.getReplicatedToAllIndex());
+ // Don't reset replicatedToAllIndex to -1 as this may prevent us from trimming the log after an
+ // install snapshot to a follower.
+ if(captureSnapshot.getReplicatedToAllIndex() >= 0) {
+ currentBehavior.setReplicatedToAllIndex(captureSnapshot.getReplicatedToAllIndex());
+ }
+
} else if(captureSnapshot.getReplicatedToAllIndex() != -1){
// clear the log based on replicatedToAllIndex
context.getReplicatedLog().snapshotPreCommit(captureSnapshot.getReplicatedToAllIndex(),
context.getReplicatedLog().getSnapshotTerm());
}
- LOG.info("{}: Removed in-memory snapshotted entries, adjusted snaphsotIndex:{} " +
- "and term:{}", persistenceId(), captureSnapshot.getLastAppliedIndex(),
- captureSnapshot.getLastAppliedTerm());
+ LOG.info("{}: Removed in-memory snapshotted entries, adjusted snaphsotIndex: {} " +
+ "and term: {}", context.getId(), context.getReplicatedLog().getSnapshotIndex(),
+ context.getReplicatedLog().getSnapshotTerm());
if (context.getId().equals(currentBehavior.getLeaderId())
&& captureSnapshot.isInstallSnapshotInitiated()) {
// this would be call straight to the leader and won't initiate in serialization
- currentBehavior.handleMessage(context.getActor(), new SendInstallSnapshot(
- ByteString.copyFrom(snapshotBytes)));
+ currentBehavior.handleMessage(context.getActor(), new SendInstallSnapshot(snapshot));
}
captureSnapshot = null;
private class Persisting extends AbstractSnapshotState {
@Override
- public void commit(DataPersistenceProvider persistenceProvider, long sequenceNumber) {
- context.getReplicatedLog().snapshotCommit();
- persistenceProvider.deleteSnapshots(new SnapshotSelectionCriteria(
+ public void commit(long sequenceNumber, RaftActorBehavior currentBehavior) {
+ LOG.debug("Snapshot success sequence number:", sequenceNumber);
+
+ if(applySnapshot != null) {
+ try {
+ applySnapshotProcedure.apply(applySnapshot.getState());
+
+ //clears the followers log, sets the snapshot index to ensure adjusted-index works
+ context.setReplicatedLog(ReplicatedLogImpl.newInstance(applySnapshot, context, currentBehavior));
+ context.setLastApplied(applySnapshot.getLastAppliedIndex());
+ context.setCommitIndex(applySnapshot.getLastAppliedIndex());
+ } catch (Exception e) {
+ LOG.error("Error applying snapshot", e);
+ }
+ } else {
+ context.getReplicatedLog().snapshotCommit();
+ }
+
+ context.getPersistenceProvider().deleteSnapshots(new SnapshotSelectionCriteria(
sequenceNumber - context.getConfigParams().getSnapshotBatchCount(), 43200000));
- persistenceProvider.deleteMessages(sequenceNumber);
+ context.getPersistenceProvider().deleteMessages(lastSequenceNumber);
+ lastSequenceNumber = -1;
+ applySnapshot = null;
SnapshotManager.this.currentState = IDLE;
}
@Override
public void rollback() {
- context.getReplicatedLog().snapshotRollback();
-
- LOG.info("{}: Replicated Log rolled back. Snapshot will be attempted in the next cycle." +
- "snapshotIndex:{}, snapshotTerm:{}, log-size:{}", persistenceId(),
- context.getReplicatedLog().getSnapshotIndex(),
- context.getReplicatedLog().getSnapshotTerm(),
- context.getReplicatedLog().size());
+ // Nothing to rollback if we're applying a snapshot from the leader.
+ if(applySnapshot == null) {
+ context.getReplicatedLog().snapshotRollback();
+
+ LOG.info("{}: Replicated Log rolled back. Snapshot will be attempted in the next cycle." +
+ "snapshotIndex:{}, snapshotTerm:{}, log-size:{}", persistenceId(),
+ context.getReplicatedLog().getSnapshotIndex(),
+ context.getReplicatedLog().getSnapshotTerm(),
+ context.getReplicatedLog().size());
+ }
+ lastSequenceNumber = -1;
+ applySnapshot = null;
SnapshotManager.this.currentState = IDLE;
}
long getTerm();
}
- private static class LastAppliedTermInformationReader implements TermInformationReader{
+ static class LastAppliedTermInformationReader implements TermInformationReader{
private long index;
private long term;
this.term = -1L;
if (!hasFollowers) {
if(lastLogEntry != null) {
+ // since we have persisted the last-log-entry to persistent journal before the capture,
+ // we would want to snapshot from this entry.
index = lastLogEntry.getIndex();
term = lastLogEntry.getTerm();
}
} else if (entry != null) {
index = entry.getIndex();
term = entry.getTerm();
- } else if(originalIndex == log.getSnapshotIndex()){
+ } else if(log.getSnapshotIndex() > -1){
index = log.getSnapshotIndex();
term = log.getSnapshotTerm();
}