From 5ac4de87753c9d2d2f3db85ddfe663258fe2e2de Mon Sep 17 00:00:00 2001
From: Evan Tschannen <ejt@apple.com>
Date: Thu, 13 Jul 2017 16:31:55 -0700
Subject: [PATCH] fix: the same tag could be in the server tags list twice

---
 fdbserver/ApplyMetadataMutation.h           | 11 +++++++----
 fdbserver/LogSystem.h                       |  2 +-
 fdbserver/TagPartitionedLogSystem.actor.cpp |  2 +-
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/fdbserver/ApplyMetadataMutation.h b/fdbserver/ApplyMetadataMutation.h
index 1fc6a29154..03c0b754a1 100644
--- a/fdbserver/ApplyMetadataMutation.h
+++ b/fdbserver/ApplyMetadataMutation.h
@@ -202,17 +202,20 @@ static void applyMetadataMutations(UID const& dbgid, Arena &arena, VectorRef<Mut
 				if(toCommit) {
 					// Notifies all servers that a Master's server epoch ends
 					auto allServers = txnStateStore->readRange(serverTagKeys).get();
+					std::set<Tag> allTags;
+					for (auto &kv : allServers)
+						allTags.insert(decodeServerTagValue(kv.value));
 
 					if (m.param1 == lastEpochEndKey) {
-						for (auto &kv : allServers)
-							toCommit->addTag(decodeServerTagValue(kv.value));
+						for (auto t : allTags)
+							toCommit->addTag(t);
 						toCommit->addTypedMessage(LogProtocolMessage());
 					}
 
 					MutationRef privatized = m;
 					privatized.param1 = m.param1.withPrefix(systemKeys.begin, arena);
-					for (auto &kv : allServers)
-						toCommit->addTag(decodeServerTagValue(kv.value));
+					for (auto t : allTags)
+						toCommit->addTag(t);
 					toCommit->addTypedMessage(privatized);
 				}
 			}
diff --git a/fdbserver/LogSystem.h b/fdbserver/LogSystem.h
index 78ae8d8c5f..d0109ba3a7 100644
--- a/fdbserver/LogSystem.h
+++ b/fdbserver/LogSystem.h
@@ -498,7 +498,7 @@ struct ILogSystem {
 
 	virtual void getPushLocations( std::vector<Tag> const& tags, vector<int>& locations ) = 0;
 
-	virtual void addRemoteTags( int logSet, std::vector<Tag> originalTags, std::vector<int>& tags ) = 0;
+	virtual void addRemoteTags( int logSet, std::vector<Tag> const& originalTags, std::vector<int>& tags ) = 0;
 
 	virtual Tag getRandomRouterTag() = 0;
 
diff --git a/fdbserver/TagPartitionedLogSystem.actor.cpp b/fdbserver/TagPartitionedLogSystem.actor.cpp
index b95ce49f49..4ea512dab1 100644
--- a/fdbserver/TagPartitionedLogSystem.actor.cpp
+++ b/fdbserver/TagPartitionedLogSystem.actor.cpp
@@ -546,7 +546,7 @@ struct TagPartitionedLogSystem : ILogSystem, ReferenceCounted<TagPartitionedLogS
 			return std::numeric_limits<Version>::max();
 	}
 
-	virtual void addRemoteTags( int logSet, std::vector<Tag> originalTags, std::vector<int>& tags ) {
+	virtual void addRemoteTags( int logSet, std::vector<Tag> const& originalTags, std::vector<int>& tags ) {
 		tLogs[logSet]->getPushLocations(originalTags, tags, SERVER_KNOBS->MAX_TAG);
 	}