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Type:
Bug
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Resolution: Fixed
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Priority:
Major - P3
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Affects Version/s: 3.6.0
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Component/s: Query Operations
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None
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Environment:openjdk version "1.8.0_151"
ubuntu v16.04
While testing the fix in JAVA-2821 for v3.7.0 (and v3.8.0-beta2) I noticed that change streams cursor resumes when the primary member fails, however only if there has been an event since the last election.
For example:
If a replica set with three members (PSS) 27017, 27018, 27019.
The primary member is currently on `27017`
- Insert on the primary 27017 -> change stream event sent
- Stop the primary 27017 -> the cursor now works in v3.7.0+ and resumes correctly
- Wait for a new primary to be elected.
- Insert on the new primary 27018 -> change stream event sent
- Stop the current primary 27018 -> cursor resumes correctly.
- Wait for a new primary to be elected.
- This time do not trigger any events on the collection (you can perform events on another collection though). Stop the new primary 27019.
- The cursor will throw an exception com.mongodb.MongoSocketReadException
Example code:
MongoClient mongoClient;
String mongoURI = "mongodb://localhost:27017,localhost:27018,localhost:27019/test?replicaSet=changestream";
mongoClient = new MongoClient(new MongoClientURI(mongoURI));
MongoDatabase database = mongoClient.getDatabase("dbname");
MongoCollection<Document> collection = database.getCollection("collname");
Block<ChangeStreamDocument<Document>> printBlock = new
Block<ChangeStreamDocument<Document>>() {
@Override
public void apply(final ChangeStreamDocument<Document> changeStreamDocument) {
System.out.println(changeStreamDocument);
}
};
MongoCursor<ChangeStreamDocument<Document>> cursor = collection.watch().iterator();
ChangeStreamDocument<Document> next = cursor.next();
System.out.println(next);
while(cursor.hasNext()){
next = cursor.next();
System.out.println(next);
}
The stack trace:
INFO: Closed connection [connectionId{localValue:35, serverValue:4}] to ironhide.local:27019 because there was a socket exception raised by this connection.
Exception in thread "main" com.mongodb.MongoSocketReadException: Prematurely reached end of stream
at com.mongodb.connection.SocketStream.read(SocketStream.java:87)
at com.mongodb.connection.InternalStreamConnection.receiveResponseBuffers(InternalStreamConnection.java:538)
at com.mongodb.connection.InternalStreamConnection.receiveMessage(InternalStreamConnection.java:409)
at com.mongodb.connection.InternalStreamConnection.receiveCommandMessageResponse(InternalStreamConnection.java:281)
at com.mongodb.connection.InternalStreamConnection.sendAndReceive(InternalStreamConnection.java:247)
at com.mongodb.connection.UsageTrackingInternalConnection.sendAndReceive(UsageTrackingInternalConnection.java:98)
at com.mongodb.connection.DefaultConnectionPool$PooledConnection.sendAndReceive(DefaultConnectionPool.java:441)
at com.mongodb.connection.CommandProtocolImpl.execute(CommandProtocolImpl.java:70)
at com.mongodb.connection.DefaultServer$DefaultServerProtocolExecutor.execute(DefaultServer.java:192)
at com.mongodb.connection.DefaultServerConnection.executeProtocol(DefaultServerConnection.java:264)
at com.mongodb.connection.DefaultServerConnection.command(DefaultServerConnection.java:126)
at com.mongodb.connection.DefaultServerConnection.command(DefaultServerConnection.java:118)
at com.mongodb.operation.QueryBatchCursor.getMore(QueryBatchCursor.java:222)
at com.mongodb.operation.QueryBatchCursor.hasNext(QueryBatchCursor.java:115)
at com.mongodb.operation.ChangeStreamBatchCursor$1.apply(ChangeStreamBatchCursor.java:58)
at com.mongodb.operation.ChangeStreamBatchCursor$1.apply(ChangeStreamBatchCursor.java:55)
at com.mongodb.operation.ChangeStreamBatchCursor.resumeableOperation(ChangeStreamBatchCursor.java:142)
at com.mongodb.operation.ChangeStreamBatchCursor.hasNext(ChangeStreamBatchCursor.java:55)
at com.mongodb.client.internal.MongoBatchCursorAdapter.hasNext(MongoBatchCursorAdapter.java:54)
at com.tour.ChangeStream.main(ChangeStream.java:53)
- is related to
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- Closed
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