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Fix Issue with Concurrent Snapshot Init + Delete #38518

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merged 5 commits into from
Feb 8, 2019
Merged

Fix Issue with Concurrent Snapshot Init + Delete #38518

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6387014
Fix Issue with Concurrent Snapshot Init + Delete
original-brownbear Feb 6, 2019
3a95407
Merge remote-tracking branch 'elastic/master' into 38489
original-brownbear Feb 6, 2019
28128cd
Merge remote-tracking branch 'elastic/master' into 38489
original-brownbear Feb 7, 2019
5aafa44
assert instead of if
original-brownbear Feb 7, 2019
46bb7a3
Merge remote-tracking branch 'elastic/master' into 38489
original-brownbear Feb 8, 2019
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19 changes: 16 additions & 3 deletions server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -331,7 +331,6 @@ public void onFailure(final Exception e) {
public TimeValue timeout() {
return request.masterNodeTimeout();
}

});
}

Expand Down Expand Up @@ -394,6 +393,8 @@ private void beginSnapshot(final ClusterState clusterState,

boolean snapshotCreated;

boolean hadAbortedInitializations;

@Override
protected void doRun() {
assert initializingSnapshots.contains(snapshot.snapshot());
Expand Down Expand Up @@ -433,6 +434,8 @@ public ClusterState execute(ClusterState currentState) {

if (entry.state() == State.ABORTED) {
entries.add(entry);
assert entry.shards().isEmpty();
hadAbortedInitializations = true;
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Since we now don't finalise this case in applyClusterState we need to end it when the cluster state for the init has been processed, so we set the flag here to mark that case.

} else {
// Replace the snapshot that was just initialized
ImmutableOpenMap<ShardId, ShardSnapshotStatus> shards =
Expand Down Expand Up @@ -491,6 +494,16 @@ public void clusterStateProcessed(String source, ClusterState oldState, ClusterS
// completion listener in this method. For the snapshot completion to work properly, the snapshot
// should still exist when listener is registered.
userCreateSnapshotListener.onResponse(snapshot.snapshot());

if (hadAbortedInitializations) {
final SnapshotsInProgress snapshotsInProgress = newState.custom(SnapshotsInProgress.TYPE);
if (snapshotsInProgress != null) {
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we should be able to assert != null here?

final SnapshotsInProgress.Entry entry = snapshotsInProgress.snapshot(snapshot.snapshot());
if (entry != null) {
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we should be able to assert != null here?

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I guess I was paranoid about potentially throwing an NPE in the cluster state thread :D but yea, assert should in theory be just fine => moving to assert :)

endSnapshot(entry);
}
}
}
}
});
}
Expand Down Expand Up @@ -701,8 +714,8 @@ public void applyClusterState(ClusterChangedEvent event) {
// 3. Snapshots in any other state that have all their shard tasks completed
snapshotsInProgress.entries().stream().filter(
entry -> entry.state().completed()
|| entry.state() == State.INIT && initializingSnapshots.contains(entry.snapshot()) == false
|| entry.state() != State.INIT && completed(entry.shards().values())
|| initializingSnapshots.contains(entry.snapshot()) == false
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@original-brownbear original-brownbear Feb 6, 2019 •
edited
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Before we were finalising all snapshots that had all their shards completed here.
This caught the case where a snapshot had just went from INIT to ABORTED and was finalised in the repository when at the same time we were initialising it in https://github.com/elastic/elasticsearch/pull/38518/files#diff-a0853be4492c052f24917b5c1464003dR413 (this is what the failing test in #38489 forced by setting the on init block in the MockRepository).

With this change we will never finalise a snapshot here that is still being initialised.

&& (entry.state() == State.INIT || completed(entry.shards().values()))
).forEach(this::endSnapshot);
}
if (newMaster) {
Expand Down
1 change: 0 additions & 1 deletion server/src/test/java/org/elasticsearch/snapshots/DedicatedClusterSnapshotRestoreIT.java
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Original file line number Diff line number Diff line change
Expand Up @@ -855,7 +855,6 @@ public void testMasterShutdownDuringSnapshot() throws Exception {
assertEquals(0, snapshotInfo.failedShards());
}


public void testMasterAndDataShutdownDuringSnapshot() throws Exception {
logger.info("--> starting three master nodes and two data nodes");
internalCluster().startMasterOnlyNodes(3);
Expand Down