we need to send notifications when the leader fitness becomes worse s…

…o that we repopulate availableCandidates to compare with the new lower fitness
apple · Aug 14, 2018 · f52d841 · f52d841
1 parent 2341e5d
commit f52d841
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Showing 2 changed files with 8 additions and 5 deletions.
diff --git a/fdbclient/CoordinationInterface.h b/fdbclient/CoordinationInterface.h
@@ -113,9 +113,11 @@ struct LeaderInfo {
 		return ((changeID.first() & mask) == (leaderInfo.changeID.first() & mask)) && changeID.second() == leaderInfo.changeID.second();
 	}
 
-	// Change leader only if the candidate has better process class fitness
+	// Change leader only if
+	// 1. the candidate has better process class fitness and the candidate is not the leader
+	// 2. the leader process class fitness becomes worse
 	bool leaderChangeRequired(LeaderInfo const& candidate) const {
-		return (changeID.first() & ~mask) > (candidate.changeID.first() & ~mask);
+		return ((changeID.first() & ~mask) > (candidate.changeID.first() & ~mask) && !equalInternalId(candidate)) || ((changeID.first() & ~mask) < (candidate.changeID.first() & ~mask) && equalInternalId(candidate));
 	}
 
 	template <class Ar>

diff --git a/fdbserver/Coordination.actor.cpp b/fdbserver/Coordination.actor.cpp
@@ -285,15 +285,16 @@ ACTOR Future<Void> leaderRegister(LeaderElectionRegInterface interf, Key key) {
 					}
 				}
 
-				if (currentNominee.present() && nextNominee.present() && currentNominee.get().equalInternalId(nextNominee.get())) {
-					currentNominee = nextNominee;
-				} else if ( !nextNominee.present() || !foundCurrentNominee || currentNominee.get().leaderChangeRequired(nextNominee.get()) ) {
+				if ( !nextNominee.present() || !foundCurrentNominee || currentNominee.get().leaderChangeRequired(nextNominee.get()) ) {
 					TraceEvent("NominatingLeader").detail("Nominee", nextNominee.present() ? nextNominee.get().changeID : UID())
 						.detail("Changed", nextNominee != currentNominee).detail("Key", printable(key));
 					for(int i=0; i<notify.size(); i++)
 						notify[i].send( nextNominee );
 					notify.clear();
 					currentNominee = nextNominee;
+				} else if (currentNominee.get().equalInternalId(nextNominee.get())) {
+					// leader becomes better
+					currentNominee = nextNominee;
 				}
 
 				if( availableLeaders.size() ) {