diff --git a/lib/mempool/mempool.js b/lib/mempool/mempool.js
index 741182ad..3d2b64c7 100644
--- a/lib/mempool/mempool.js
+++ b/lib/mempool/mempool.js
@@ -724,7 +724,7 @@ Mempool.prototype.removeUnchecked = function removeUnchecked(entry, limit) {
   // are still spending valid coins (which
   // now exist on the blockchain).
   if (limit) {
-    this._removeSpenders(entry);
+    this.removeSpenders(entry);
     this.logger.debug('Evicting %s from the mempool.', entry.tx.rhash);
   }
 
@@ -976,6 +976,58 @@ Mempool.prototype.countDescendants = function countDescendants(tx) {
   return max;
 };
 
+/**
+ * Get all transaction ancestors.
+ * @param {TX} tx
+ * @returns {MempoolEntry[]}
+ */
+
+Mempool.prototype.getAncestors = function getAncestors(tx) {
+  var self = this;
+  var entries = [];
+
+  (function traverse(tx) {
+    var i, input, prev;
+
+    for (i = 0; i < tx.inputs.length; i++) {
+      input = tx.inputs[i];
+      prev = self.getTX(input.prevout.hash);
+      if (!prev)
+        continue;
+      entries.push(prev);
+      traverse(prev);
+    }
+  })(tx);
+
+  return entries;
+};
+
+/**
+ * Get all a transaction descendants.
+ * @param {TX} tx
+ * @returns {MempoolEntry[]}
+ */
+
+Mempool.prototype.getDescendants = function getDescendants(tx) {
+  var self = this;
+  var entries = [];
+
+  (function traverse(tx) {
+    var hash = tx.hash('hex');
+    var i, next;
+
+    for (i = 0; i < tx.outputs.length; i++) {
+      next = self.isSpent(hash, i);
+      if (!next)
+        continue;
+      entries.push(next);
+      traverse(next.tx);
+    }
+  })(tx);
+
+  return entries;
+};
+
 /**
  * Find a unconfirmed transactions that
  * this transaction depends on.
@@ -1387,7 +1439,7 @@ Mempool.prototype.trackEntry = function trackEntry(entry) {
     assert(input.coin);
 
     if (this.options.indexAddress)
-      this.coinIndex.removeCoin(input.coin);
+      this.coinIndex.removeCoin(input.prevout);
 
     this.spents[key] = entry;
   }
@@ -1430,12 +1482,10 @@ Mempool.prototype.untrackEntry = function untrackEntry(entry) {
     input = tx.inputs[i];
     key = input.prevout.hash + input.prevout.index;
 
-    delete this.spents[key];
-
-    assert(input.coin);
-
     if (this.options.indexAddress)
-      this.coinIndex.removeCoin(input.coin);
+      this.coinIndex.removeCoin(input.prevout);
+
+    delete this.spents[key];
   }
 
   if (this.options.indexAddress) {
@@ -1462,7 +1512,7 @@ Mempool.prototype.untrackEntry = function untrackEntry(entry) {
  * @param {Function} callback
  */
 
-Mempool.prototype._removeSpenders = function _removeSpenders(entry) {
+Mempool.prototype.removeSpenders = function removeSpenders(entry) {
   var tx = entry.tx;
   var hash = tx.hash('hex');
   var i, spender;
@@ -1855,6 +1905,7 @@ AddressIndex.prototype.getTX = function getTX(address) {
 };
 
 AddressIndex.prototype.addTX = function addTX(tx) {
+  var key = tx.hash('hex');
   var hashes = tx.getHashes('hex');
   var i, hash, items;
 
@@ -1869,12 +1920,18 @@ AddressIndex.prototype.addTX = function addTX(tx) {
 
     utils.binaryInsert(items, tx.hash(), utils.cmp);
   }
+
+  this.map[key] = hashes;
 };
 
 AddressIndex.prototype.removeTX = function removeTX(tx) {
-  var hashes = tx.getHashes('hex');
+  var key = tx.hash('hex');
+  var hashes = this.map[key];
   var i, hash, items;
 
+  if (!hashes)
+    return;
+
   for (i = 0; i < hashes.length; i++) {
     hash = hashes[i];
     items = this.map[hash];
@@ -1887,9 +1944,12 @@ AddressIndex.prototype.removeTX = function removeTX(tx) {
     if (items.length === 0)
       delete this.map[hash];
   }
+
+  delete this.map[key];
 };
 
 AddressIndex.prototype.addCoin = function addCoin(coin) {
+  var key = coin.hash + coin.index;
   var hash = coin.getHash('hex');
   var outpoint, items;
 
@@ -1905,10 +1965,13 @@ AddressIndex.prototype.addCoin = function addCoin(coin) {
 
   outpoint = bcoin.outpoint(coin.hash, coin.index).toRaw();
   utils.binaryInsert(items, outpoint, utils.cmp);
+
+  this.map[key] = hash;
 };
 
 AddressIndex.prototype.removeCoin = function removeCoin(coin) {
-  var hash = coin.getHash('hex');
+  var key = coin.hash + coin.index;
+  var hash = this.map[key];
   var outpoint, items;
 
   if (!hash)
@@ -1924,6 +1987,8 @@ AddressIndex.prototype.removeCoin = function removeCoin(coin) {
 
   if (items.length === 0)
     delete this.map[hash];
+
+  delete this.map[key];
 };
 
 /*