diff --git a/src/addressindex.h b/src/addressindex.h
index b6e3587c1..43b49dca9 100644
--- a/src/addressindex.h
+++ b/src/addressindex.h
@@ -57,7 +57,7 @@ struct CMempoolAddressDeltaKey
 
 struct CMempoolAddressDeltaKeyCompare
 {
-    bool operator()(const CMempoolAddressDeltaKey& a, const CMempoolAddressDeltaKey& b) {
+    bool operator()(const CMempoolAddressDeltaKey& a, const CMempoolAddressDeltaKey& b) const {
         if (a.type == b.type) {
             if (a.addressBytes == b.addressBytes) {
                 if (a.txhash == b.txhash) {
diff --git a/src/txdb.cpp b/src/txdb.cpp
index 4843735aa..4b505af97 100644
--- a/src/txdb.cpp
+++ b/src/txdb.cpp
@@ -401,7 +401,7 @@ bool CBlockTreeDB::ReadAddressIndex(uint160 addressHash, int type,
 
 bool CBlockTreeDB::WriteTimestampIndex(const CTimestampIndexKey &timestampIndex) {
     CDBBatch batch(*this);
-    batch.Write(make_pair(DB_TIMESTAMPINDEX, timestampIndex), NULL);
+    batch.Write(make_pair(DB_TIMESTAMPINDEX, timestampIndex), 0);
     return WriteBatch(batch);
 }