Interface SnapshotState
- All Known Implementing Classes:
SnapshotManager
public interface SnapshotState
Interface for a snapshot phase state.
- Author:
- Moiz Raja, Thomas Pantelis
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Method Summary
Modifier and TypeMethodDescriptionvoidapply(ApplySnapshot snapshot) Applies a snapshot on a follower that was installed by the leader.booleancapture(RaftEntryMeta lastLogEntry, long replicatedToAllIndex) Initiates a capture snapshot.booleancaptureToInstall(RaftEntryMeta lastLogEntry, long replicatedToAllIndex, String targetFollower) Initiates a capture snapshot for the purposing of installing the snapshot on a follower.booleancaptureWithForcedTrim(RaftEntryMeta lastLogEntry, long replicatedToAllIndex) Initiates a capture snapshot, while enforcing trimming of the log up to lastAppliedIndex.voidcommit(long sequenceNumber, long timeStamp) Commit the snapshot by trimming the log.booleanReturns whether or not a capture is in progress.voidpersist(Snapshot.State snapshotState, Optional<OutputStream> installSnapshotStream, long totalMemory) Persists a snapshot.voidrollback()Rolls back the snapshot on failure.longtrimLog(long desiredTrimIndex) Trims the in-memory log.
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Method Details
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isCapturing
boolean isCapturing()Returns whether or not a capture is in progress.- Returns:
- true when a snapshot is being captured, false otherwise
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capture
Initiates a capture snapshot.- Parameters:
lastLogEntry- the last entry in the replicated logreplicatedToAllIndex- the current replicatedToAllIndex- Returns:
- true if capture was started
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captureToInstall
boolean captureToInstall(RaftEntryMeta lastLogEntry, long replicatedToAllIndex, String targetFollower) Initiates a capture snapshot for the purposing of installing the snapshot on a follower.- Parameters:
lastLogEntry- the last entry in the replicated logreplicatedToAllIndex- the current replicatedToAllIndextargetFollower- the id of the follower on which to install- Returns:
- true if capture was started
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captureWithForcedTrim
Initiates a capture snapshot, while enforcing trimming of the log up to lastAppliedIndex.- Parameters:
lastLogEntry- the last entry in the replicated logreplicatedToAllIndex- the current replicatedToAllIndex- Returns:
- true if capture was started
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apply
Applies a snapshot on a follower that was installed by the leader.- Parameters:
snapshot- the Snapshot to apply.
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persist
void persist(Snapshot.State snapshotState, Optional<OutputStream> installSnapshotStream, long totalMemory) Persists a snapshot.- Parameters:
snapshotState- the snapshot StateinstallSnapshotStream- Optional OutputStream that is present if the snapshot is to also be installed on a follower.totalMemory- the total memory threshold
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commit
void commit(long sequenceNumber, long timeStamp) Commit the snapshot by trimming the log.- Parameters:
sequenceNumber- the sequence number of the persisted snapshottimeStamp- the time stamp of the persisted snapshot
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rollback
void rollback()Rolls back the snapshot on failure. -
trimLog
long trimLog(long desiredTrimIndex) Trims the in-memory log.- Parameters:
desiredTrimIndex- the desired index to trim from- Returns:
- the actual trim index
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