diff --git a/fdbclient/MasterProxyInterface.h b/fdbclient/MasterProxyInterface.h
index 784331384b..89eb9d5eca 100644
--- a/fdbclient/MasterProxyInterface.h
+++ b/fdbclient/MasterProxyInterface.h
@@ -104,7 +104,7 @@ struct CommitID {
 	Version version; 			// returns invalidVersion if transaction conflicts
 	uint16_t txnBatchId;
 	Optional<Value> metadataVersion;
-	Optional<std::vector<int>> conflictingKRIndices;
+	Optional<Standalone<VectorRef<int>>> conflictingKRIndices;
 
 	template <class Ar>
 	void serialize(Ar& ar) {
@@ -112,7 +112,7 @@ struct CommitID {
 	}
 
 	CommitID() : version(invalidVersion), txnBatchId(0) {}
-	CommitID( Version version, uint16_t txnBatchId, const Optional<Value>& metadataVersion, const Optional<std::vector<int>>& conflictingKRIndices = Optional<std::vector<int>>() ) : version(version), txnBatchId(txnBatchId), metadataVersion(metadataVersion), conflictingKRIndices(conflictingKRIndices) {}
+	CommitID( Version version, uint16_t txnBatchId, const Optional<Value>& metadataVersion, const Optional<Standalone<VectorRef<int>>>& conflictingKRIndices = Optional<Standalone<VectorRef<int>>>() ) : version(version), txnBatchId(txnBatchId), metadataVersion(metadataVersion), conflictingKRIndices(conflictingKRIndices) {}
 };
 
 struct CommitTransactionRequest : TimedRequest {
diff --git a/fdbserver/ConflictSet.h b/fdbserver/ConflictSet.h
index ffe80e0e6d..3284f9f4ab 100644
--- a/fdbserver/ConflictSet.h
+++ b/fdbserver/ConflictSet.h
@@ -33,7 +33,7 @@ void clearConflictSet( ConflictSet*, Version );
 void destroyConflictSet(ConflictSet*);
 
 struct ConflictBatch {
-	explicit ConflictBatch( ConflictSet*,  std::map< int, std::vector< int > >* conflictingKeyRangeMap = nullptr);
+	explicit ConflictBatch( ConflictSet*,  std::map< int, VectorRef< int > >* conflictingKeyRangeMap = nullptr, Arena* resolveBatchReplyArena = nullptr);
 	~ConflictBatch();
 
 	enum TransactionCommitResult {
@@ -54,7 +54,8 @@ private:
 	std::vector< std::pair<StringRef,StringRef> > combinedWriteConflictRanges;
 	std::vector< struct ReadConflictRange > combinedReadConflictRanges;
 	bool* transactionConflictStatus;
-	std::map< int, std::vector< int > >* conflictingKeyRangeMap;
+	std::map< int, VectorRef< int > >* conflictingKeyRangeMap;
+	Arena* resolveBatchReplyArena;
 
 	void checkIntraBatchConflicts();
 	void combineWriteConflictRanges();
diff --git a/fdbserver/MasterProxyServer.actor.cpp b/fdbserver/MasterProxyServer.actor.cpp
index 7b4aaab6bc..01be822575 100644
--- a/fdbserver/MasterProxyServer.actor.cpp
+++ b/fdbserver/MasterProxyServer.actor.cpp
@@ -1034,15 +1034,15 @@ ACTOR Future<Void> commitBatch(
 		else {
 			// If enable the option to report conflicting keys from resolvers, we union all conflicting key ranges here and send back through CommitID
 			if (trs[t].transaction.report_conflicting_keys) {
-				std::vector<int> conflictingKRIndices;
+				Standalone<VectorRef<int>> conflictingKRIndices;
 				for (int resolverInd : transactionResolverMap[t]) {
-					const std::vector<int>& cKRs = resolution[resolverInd].conflictingKeyRangeMap.get()[nextTr[resolverInd]];
+					auto const & cKRs = resolution[resolverInd].conflictingKeyRangeMap[nextTr[resolverInd]];
 					for (auto const & rCRIndex : cKRs)
-						conflictingKRIndices.emplace_back(rCRIndex);
+						conflictingKRIndices.push_back(conflictingKRIndices.arena(), rCRIndex);
 				}
 				// At least one keyRange index should be returned
 				ASSERT(conflictingKRIndices.size());
-				trs[t].reply.send(CommitID(invalidVersion, t, Optional<Value>(), Optional<std::vector<int>>(conflictingKRIndices)));
+				trs[t].reply.send(CommitID(invalidVersion, t, Optional<Value>(), Optional<Standalone<VectorRef<int>>>(conflictingKRIndices)));
 			} else {
 				trs[t].reply.sendError(not_committed());
 			}
diff --git a/fdbserver/Resolver.actor.cpp b/fdbserver/Resolver.actor.cpp
index 2f0933d5c8..57700e4105 100644
--- a/fdbserver/Resolver.actor.cpp
+++ b/fdbserver/Resolver.actor.cpp
@@ -130,14 +130,15 @@ ACTOR Future<Void> resolveBatch(
 		if(req.debugID.present())
 			g_traceBatch.addEvent("CommitDebug", debugID.get().first(), "Resolver.resolveBatch.AfterOrderer");
 		
+		ResolveTransactionBatchReply &reply = proxyInfo.outstandingBatches[req.version];
+
 		vector<int> commitList;
 		vector<int> tooOldList;
-		std::map< int, std::vector< int > > conflictingKeyRangeMap;
 
 		// Detect conflicts
 		double expire = now() + SERVER_KNOBS->SAMPLE_EXPIRATION_TIME;
 		double tstart = timer();
-		ConflictBatch conflictBatch(self->conflictSet, &conflictingKeyRangeMap);
+		ConflictBatch conflictBatch(self->conflictSet, &reply.conflictingKeyRangeMap, &reply.arena);
 		int keys = 0;
 		for(int t=0; t<req.transactions.size(); t++) {
 			conflictBatch.addTransaction( req.transactions[t] );
@@ -156,7 +157,6 @@ ACTOR Future<Void> resolveBatch(
 		g_counters.conflictTransactions += req.transactions.size();
 		g_counters.conflictKeys += keys;
 
-		ResolveTransactionBatchReply &reply = proxyInfo.outstandingBatches[req.version];
 		reply.debugID = req.debugID;
 		reply.committed.resize( reply.arena, req.transactions.size() );
 		for(int c=0; c<commitList.size(); c++)
@@ -164,9 +164,6 @@ ACTOR Future<Void> resolveBatch(
 
 		for (int c = 0; c<tooOldList.size(); c++)
 			reply.committed[tooOldList[c]] = ConflictBatch::TransactionTooOld;
-		
-		if (!conflictingKeyRangeMap.empty())
-			reply.conflictingKeyRangeMap = std::move(conflictingKeyRangeMap);
 
 		ASSERT(req.prevVersion >= 0 || req.txnStateTransactions.size() == 0); // The master's request should not have any state transactions
 
diff --git a/fdbserver/ResolverInterface.h b/fdbserver/ResolverInterface.h
index d53779a5c7..e1f74707b9 100644
--- a/fdbserver/ResolverInterface.h
+++ b/fdbserver/ResolverInterface.h
@@ -77,11 +77,11 @@ struct ResolveTransactionBatchReply {
 	VectorRef<uint8_t> committed;
 	Optional<UID> debugID;
 	VectorRef<VectorRef<StateTransactionRef>> stateMutations;  // [version][transaction#] -> (committed, [mutation#])
-	Optional<std::map<int, std::vector<int>>> conflictingKeyRangeMap; // transaction index -> conflicting read_conflict_range ids given by the resolver
+	std::map<int, VectorRef<int>> conflictingKeyRangeMap; // transaction index -> conflicting read_conflict_range ids given by the resolver
 
 	template <class Archive>
 	void serialize(Archive& ar) {
-		serializer(ar, committed, stateMutations, arena, debugID, conflictingKeyRangeMap);
+		serializer(ar, committed, stateMutations, debugID, conflictingKeyRangeMap, arena);
 	}
 
 };
diff --git a/fdbserver/SkipList.cpp b/fdbserver/SkipList.cpp
index 038214cd60..3f1b6af859 100644
--- a/fdbserver/SkipList.cpp
+++ b/fdbserver/SkipList.cpp
@@ -123,10 +123,12 @@ struct ReadConflictRange {
 	StringRef begin, end;
 	Version version;
 	int transaction;
-	std::vector<int>* conflictingKeyRange;
 	int indexInTx;
-	ReadConflictRange( StringRef begin, StringRef end, Version version, int transaction, int indexInTx, std::vector<int> * cKR = nullptr )
-		: begin(begin), end(end), version(version), transaction(transaction), indexInTx(indexInTx), conflictingKeyRange(cKR)
+	VectorRef<int>* conflictingKeyRange;
+	Arena* cKRArena;
+	
+	ReadConflictRange( StringRef begin, StringRef end, Version version, int transaction, int indexInTx, VectorRef<int> * cKR = nullptr, Arena* cKRArena = nullptr)
+		: begin(begin), end(end), version(version), transaction(transaction), indexInTx(indexInTx), conflictingKeyRange(cKR), cKRArena(cKRArena)
 	{
 	}
 	bool operator<(const ReadConflictRange& rhs) const { return compare(begin, rhs.begin)<0; }
@@ -531,7 +533,7 @@ public:
 
 		int started = min(M,count);
 		for(int i=0; i<started; i++){
-			inProgress[i].init( ranges[i], header, transactionConflictStatus, ranges[i].indexInTx, ranges[i].conflictingKeyRange );
+			inProgress[i].init( ranges[i], header, transactionConflictStatus, ranges[i].indexInTx, ranges[i].conflictingKeyRange, ranges[i].cKRArena );
 			nextJob[i] = i+1;
 		}
 		nextJob[started-1] = 0;
@@ -548,7 +550,7 @@ public:
 				}
 				else {
 					int temp = started++;
-					inProgress[job].init( ranges[temp], header, transactionConflictStatus, ranges[temp].indexInTx, ranges[temp].conflictingKeyRange );
+					inProgress[job].init( ranges[temp], header, transactionConflictStatus, ranges[temp].indexInTx, ranges[temp].conflictingKeyRange, ranges[temp].cKRArena );
 				}
 			}
 			prevJob = job;
@@ -762,13 +764,15 @@ private:
 		bool *result;
 		int state;
 		int indexInTx;
-		std::vector<int>* conflictingKeyRange; // null if report_conflicting_keys is not enabled.
+		VectorRef<int>* conflictingKeyRange; // null if report_conflicting_keys is not enabled.
+		Arena* cKRArena; // null if report_conflicting_keys is not enabled.
 
-		void init( const ReadConflictRange& r, Node* header, bool* tCS, int indexInTx, std::vector<int>* cKR) {
+		void init( const ReadConflictRange& r, Node* header, bool* tCS, int indexInTx, VectorRef<int>* cKR, Arena* cKRArena) {
 			this->start.init( r.begin, header );
 			this->end.init( r.end, header );
 			this->version = r.version;
 			this->indexInTx = indexInTx;
+			this->cKRArena = cKRArena;
 			result = &tCS[ r.transaction ];
 			conflictingKeyRange = cKR;
 			this->state = 0;
@@ -778,7 +782,7 @@ private:
 		bool conflict() { 
 			*result = true;
 			if(conflictingKeyRange != nullptr)
-				conflictingKeyRange->push_back(indexInTx);
+				conflictingKeyRange->push_back(*cKRArena, indexInTx);
 			return true;
 		}
 
@@ -974,8 +978,8 @@ void destroyConflictSet(ConflictSet* cs) {
 	delete cs;
 }
 
-ConflictBatch::ConflictBatch( ConflictSet* cs, std::map< int, std::vector< int > >* conflictingKeyRangeMap )
-	: cs(cs), transactionCount(0), conflictingKeyRangeMap(conflictingKeyRangeMap)
+ConflictBatch::ConflictBatch( ConflictSet* cs, std::map< int, VectorRef< int > >* conflictingKeyRangeMap, Arena* resolveBatchReplyArena )
+	: cs(cs), transactionCount(0), conflictingKeyRangeMap(conflictingKeyRangeMap),resolveBatchReplyArena(resolveBatchReplyArena)
 {
 }
 
@@ -1010,7 +1014,9 @@ void ConflictBatch::addTransaction( const CommitTransactionRef& tr ) {
 			points.emplace_back(range.begin, false, true, false, t, &info->readRanges[r].first);
 			//points.back().keyEnd = StringRef(buf,range.second);
 			points.emplace_back(range.end, false, false, false, t, &info->readRanges[r].second);
-			combinedReadConflictRanges.emplace_back(range.begin, range.end, tr.read_snapshot, t, r, tr.report_conflicting_keys ? &(*conflictingKeyRangeMap)[t] : nullptr);
+			combinedReadConflictRanges.emplace_back(range.begin, range.end, tr.read_snapshot, t, r,
+				tr.report_conflicting_keys ? &(*conflictingKeyRangeMap)[t] : nullptr,
+				tr.report_conflicting_keys ? resolveBatchReplyArena : nullptr);
 		}
 		for(int r=0; r<tr.write_conflict_ranges.size(); r++) {
 			const KeyRangeRef& range = tr.write_conflict_ranges[r];
@@ -1158,7 +1164,7 @@ void ConflictBatch::checkIntraBatchConflicts() {
 		for(int i=0; i<tr.readRanges.size(); i++){
 			if ( mcs.any( tr.readRanges[i].first , tr.readRanges[i].second ) ) {
 				if (tr.reportConflictingKeys){
-					(*conflictingKeyRangeMap)[t].push_back(i);
+					(*conflictingKeyRangeMap)[t].push_back(*resolveBatchReplyArena, i);
 				}
 				conflict = true;
 				break;