/**
* Set up the request processors for an Observer: firstProcesor->commitProcessor->finalProcessor
*/
@Override
protected void setupRequestProcessors() {
// We might consider changing the processor behaviour of
// Observers to, for example, remove the disk sync requirements.
// Currently, they behave almost exactly the same as followers.
RequestProcessor finalProcessor = new FinalRequestProcessor(this);
commitProcessor =
new CommitProcessor(
finalProcessor, Long.toString(getServerId()), true, getZooKeeperServerListener());
commitProcessor.start();
firstProcessor = new ObserverRequestProcessor(this, commitProcessor);
((ObserverRequestProcessor) firstProcessor).start();
/*
* Observer should write to disk, so that the it won't request
* too old txn from the leader which may lead to getting an entire
* snapshot.
*
* However, this may degrade performance as it has to write to disk
* and do periodic snapshot which may double the memory requirements
*/
if (syncRequestProcessorEnabled) {
syncProcessor = new SyncRequestProcessor(this, null);
syncProcessor.start();
}
}
