diff --git a/lib/blockchain/chain.js b/lib/blockchain/chain.js
index 9b07b33b..6c041bfd 100644
--- a/lib/blockchain/chain.js
+++ b/lib/blockchain/chain.js
@@ -2268,6 +2268,7 @@ Chain.prototype.getLocks = co(function* getLocks(prev, tx, view, flags) {
   var disableFlag = constants.sequence.DISABLE_FLAG;
   var typeFlag = constants.sequence.TYPE_FLAG;
   var hasFlag = flags & constants.flags.VERIFY_SEQUENCE;
+  var nextHeight = this.height + 1;
   var minHeight = -1;
   var minTime = -1;
   var coinHeight, coinTime;
@@ -2285,7 +2286,7 @@ Chain.prototype.getLocks = co(function* getLocks(prev, tx, view, flags) {
     coinHeight = view.getHeight(input);
 
     if (coinHeight === -1)
-      coinHeight = this.height + 1;
+      coinHeight = nextHeight;
 
     if ((input.sequence & typeFlag) === 0) {
       coinHeight += (input.sequence & mask) - 1;
diff --git a/lib/mempool/mempool.js b/lib/mempool/mempool.js
index f4bca289..31953c78 100644
--- a/lib/mempool/mempool.js
+++ b/lib/mempool/mempool.js
@@ -1500,13 +1500,13 @@ Mempool.prototype.isDoubleSpend = function isDoubleSpend(tx) {
 };
 
 /**
- * Get coin viewpoint.
+ * Get coin viewpoint (no lock).
  * @param {TX} tx
  * @param {CoinView} view
  * @returns {Promise} - Returns {@link CoinView}.
  */
 
-Mempool.prototype.getCoinView = co(function* getCoinView(tx) {
+Mempool.prototype._getCoinView = co(function* getCoinView(tx) {
   var view = new CoinView();
   var prevout = tx.getPrevout();
   var i, entry, hash, coins;
@@ -1535,6 +1535,35 @@ Mempool.prototype.getCoinView = co(function* getCoinView(tx) {
   return view;
 });
 
+/**
+ * Get coin viewpoint (lock).
+ * @param {TX} tx
+ * @param {CoinView} view
+ * @returns {Promise} - Returns {@link CoinView}.
+ */
+
+Mempool.prototype.getCoinView = co(function* getCoinView(tx) {
+  var view = yield this.chain.getCoinView(tx);
+  var entries = view.toArray();
+  var i, entry, coins;
+
+  for (i = 0; i < entries.length; i++) {
+    coins = entries[i];
+
+    if (!coins.isEmpty())
+      continue;
+
+    entry = this.getEntry(coins.hash);
+
+    if (!entry)
+      continue;
+
+    view.addTX(entry.tx, -1);
+  }
+
+  return view;
+});
+
 /**
  * Spend coins for transaction.
  * @param {TX} tx