Fix old snapshot read in consecutive snapshot synchronization #217
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added 4 commits
October 25, 2023 11:41
State transition will depend on callers of the state update function.
RaftActor of the source replica group of the synchronization can execute compactions during snapshot synchronization. In such a case, the single SnapshotSyncManager instance could perform multiple snapshot synchronizations in serial order. If the SnapsotSyncManager does so, it could read an old snapshot in the newer synchronization. This old snapshot read is related to the following aspects: * SnapshotSyncManager reads snapshots from a SnapshotStore that the SnapshotSyncManager spawns as its descendant. The SnapshotStore is a different instance from a SnapshotStore running as a descendant of RaftActor of the source replica group. The SnapshotStore cannot read new snapshots the other one wrote (by such as compaction) if it has already recovered from persisted data. * SnapshotSyncManager reuses an instance of SnapshotStore among multiple snapshot synchronizations. It cannot read a new snapshot written by a compaction that happens during the synchronization. Change SnapshotSyncManager such that it executes only one snapshot synchronization in its lifecycle. That means SnapshotSyncManager doesn't reuse SnapshotStore instances. Each synchronization will be performed by a different SnapshotSyncManager instance and in serial order.
SnapshotSyncManager no longer needs the Stop messages. It can decide immediately to stop itself in the finalizing state.
xirc
commented
Oct 26, 2023
core/src/main/scala/lerna/akka/entityreplication/raft/snapshot/sync/SnapshotSyncManager.scala
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Use SnapshotSyncManagerFinalizingSpec instead. It will contain tests for non-persistence features in the finalizing state.
…hot-synchronization
negokaz
reviewed
Oct 31, 2023
...cala/lerna/akka/entityreplication/raft/snapshot/sync/SnapshotSyncManagerFinalizingSpec.scala
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...cala/lerna/akka/entityreplication/raft/snapshot/sync/SnapshotSyncManagerFinalizingSpec.scala
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...src/test/scala/lerna/akka/entityreplication/raft/snapshot/sync/SnapshotSyncManagerSpec.scala
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negokaz
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fix-old-snapshot-read-in-consecutive-snapshot-synchronization
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Closes #215
Changes SnapshotSyncManager such that it executes only one snapshotsynchronization in its lifecycle. That means SnapshotSyncManager doesn't reuse SnapshotStore instances. Each synchronization will be performed by a different SnapshotSyncManager instance and in serial order.
TODO: