diff --git a/lib/bcoin/mempool.js b/lib/bcoin/mempool.js
index c425ec0c..9bc7b1d4 100644
--- a/lib/bcoin/mempool.js
+++ b/lib/bcoin/mempool.js
@@ -10,8 +10,6 @@ module.exports = function(bcoin) {
 /*
  * Database Layout:
  *  (inherits all from txdb)
- *  o/[hash] -> orphan/waiting hashes
- *  O/[hash] -> orphan tx
  */
 
 var EventEmitter = require('events').EventEmitter;
@@ -43,7 +41,7 @@ var DUMMY = new Buffer([0]);
  * @property {Boolean} loaded
  * @property {Object} db
  * @property {Number} size
- * @property {Number} orphans
+ * @property {Number} totalOrphans
  * @property {Locker} locker
  * @property {Number} freeCount
  * @property {Number} lastTime
@@ -76,7 +74,9 @@ function Mempool(options) {
   this.db = null;
   this.tx = null;
   this.size = 0;
-  this.orphans = 0;
+  this.waiting = {};
+  this.orphans = {};
+  this.totalOrphans = 0;
   this.spent = 0;
   this.total = 0;
 
@@ -406,47 +406,14 @@ Mempool.prototype.limitMempoolSize = function limitMempoolSize(callback) {
 
 Mempool.prototype.pruneOrphans = function pruneOrphans(callback) {
   var self = this;
-  var hashes = [];
-  var iter;
 
   callback = utils.ensure(callback);
 
-  iter = this.db.iterator({
-    gte: 'O',
-    lte: 'O~',
-    keys: true,
-    values: false,
-    fillCache: false,
-    keyAsBuffer: false
-  });
-
-  function done(err) {
-    if (err)
-      return callback(err);
-
-    utils.forEachSerial(hashes, function(hash, next) {
-      if (self.orphans <= constants.mempool.MAX_ORPHAN_TX)
-        return next();
-      self.removeOrphan(hash, next);
-    }, callback);
-  }
-
-  (function next() {
-    iter.next(function(err, key, value) {
-      if (err) {
-        return iter.end(function() {
-          callback(err);
-        });
-      }
-
-      if (key === undefined)
-        return iter.end(done);
-
-      hashes.push(key.split('/')[1]);
-
-      next();
-    });
-  })();
+  utils.forEachSerial(Object.keys(this.orphans), function(hash, next) {
+    if (self.totalOrphans <= constants.mempool.MAX_ORPHAN_TX)
+      return next();
+    self.removeOrphan(hash, next);
+  }, callback);
 };
 
 /**
@@ -1020,7 +987,7 @@ Mempool.prototype.countAncestors = function countAncestors(tx, callback) {
 Mempool.prototype.storeOrphan = function storeOrphan(tx, callback, force) {
   var self = this;
   var prevout = {};
-  var i, hash, batch, input, p;
+  var i, hash, batch, input, prev;
 
   if (tx.getSize() > 5000) {
     bcoin.debug('Ignoring large orphan: %s', tx.rhash);
@@ -1028,7 +995,6 @@ Mempool.prototype.storeOrphan = function storeOrphan(tx, callback, force) {
   }
 
   hash = tx.hash('hex');
-  batch = this.db.batch();
 
   for (i = 0; i < tx.inputs.length; i++) {
     input = tx.inputs[i];
@@ -1040,40 +1006,25 @@ Mempool.prototype.storeOrphan = function storeOrphan(tx, callback, force) {
 
   assert(prevout.length > 0);
 
-  utils.forEachSerial(prevout, function(prev, next) {
-    self.getWaiting(prev, function(err, orphans, buf) {
+  for (i = 0; i < prevout.length; i++) {
+    prev = prevout[i];
+    if (!this.waiting[prev])
+      this.waiting[prev] = [];
+    this.waiting[prev].push(hash);
+  }
+
+  this.orphans[hash] = tx.toExtended(true);
+  this.totalOrphans++;
+
+  if (self.totalOrphans > constants.mempool.MAX_ORPHAN_TX) {
+    return self.pruneOrphans(function(err) {
       if (err)
-        return next(err);
-
-      p = new BufferWriter();
-
-      if (buf)
-        p.writeBytes(buf);
-
-      p.writeHash(hash);
-
-      batch.put('o/' + prev, p.render());
-
-      next();
+        return callback(err);
+      callback();
     });
-  }, function(err) {
-    if (err)
-      return callback(err);
+  }
 
-    self.orphans++;
-
-    batch.put('O/' + hash, tx.toExtended(true));
-
-    if (self.orphans > constants.mempool.MAX_ORPHAN_TX) {
-      return self.pruneOrphans(function(err) {
-        if (err)
-          return callback(err);
-        batch.write(callback);
-      });
-    }
-
-    batch.write(callback);
-  });
+  return callback();
 };
 
 /**
@@ -1101,28 +1052,7 @@ Mempool.prototype.getHistory = function getHistory(callback) {
  */
 
 Mempool.prototype.getWaiting = function getWaiting(hash, callback) {
-  var self = this;
-  var hashes = [];
-  var p;
-
-  this.db.get('o/' + hash, function(err, buf) {
-    if (err && err.type !== 'NotFoundError')
-      return callback(err);
-
-    if (!buf)
-      return callback(null, hashes, buf);
-
-    p = new BufferReader(buf);
-
-    try {
-      while (p.left())
-        hashes.push(p.readHash('hex'));
-    } catch (e) {
-      return callback(e);
-    }
-
-    return callback(null, hashes, buf);
-  });
+  return callback(null, this.waiting[hash] || []);
 };
 
 /**
@@ -1133,22 +1063,18 @@ Mempool.prototype.getWaiting = function getWaiting(hash, callback) {
 
 Mempool.prototype.getOrphan = function getOrphan(orphanHash, callback) {
   var self = this;
+  var orphan = this.orphans[orphanHash];
 
-  this.db.get('O/' + orphanHash, function(err, orphan) {
-    if (err && err.type !== 'NotFoundError')
-      return callback(err);
+  if (!orphan)
+    return callback();
 
-    if (!orphan)
-      return callback();
+  try {
+    orphan = bcoin.tx.fromExtended(orphan, true);
+  } catch (e) {
+    return callback(e);
+  }
 
-    try {
-      orphan = bcoin.tx.fromExtended(orphan, true);
-    } catch (e) {
-      return callback(e);
-    }
-
-    return callback(null, orphan);
-  });
+  return callback(null, orphan);
 };
 
 /**
@@ -1157,12 +1083,7 @@ Mempool.prototype.getOrphan = function getOrphan(orphanHash, callback) {
  */
 
 Mempool.prototype.hasOrphan = function hasOrphan(orphanHash, callback) {
-  this.db.get('O/' + orphanHash, function(err, orphan) {
-    if (err && err.type !== 'NotFoundError')
-      return callback(err);
-
-    return callback(null, orphan != null);
-  });
+  return callback(null, this.orphans[orphanHash] != null);
 };
 
 /**
@@ -1178,7 +1099,6 @@ Mempool.prototype.resolveOrphans = function resolveOrphans(tx, callback, force)
   var self = this;
   var hash = tx.hash('hex');
   var resolved = [];
-  var batch = this.db.batch();
 
   this.getWaiting(hash, function(err, hashes) {
     if (err)
@@ -1195,29 +1115,23 @@ Mempool.prototype.resolveOrphans = function resolveOrphans(tx, callback, force)
         orphan.fillCoins(tx);
 
         if (orphan.hasCoins()) {
-          self.orphans--;
-          batch.del('O/' + orphanHash);
+          self.totalOrphans--;
+          delete self.orphans[orphanHash];
           resolved.push(orphan);
           return next();
         }
 
-        batch.put('O/' + orphanHash, orphan.toExtended(true));
+        self.orphans[orphanHash] = orphan.toExtended(true);
+
         next();
       });
     }, function(err) {
       if (err)
         return callback(err);
 
-      function done(err) {
-        if (err)
-          return callback(err);
+      delete self.waiting[hash];
 
-        return callback(null, resolved);
-      }
-
-      batch.del('o/' + hash);
-
-      return batch.write(done);
+      return callback(null, resolved);
     });
   });
 };
@@ -1230,7 +1144,7 @@ Mempool.prototype.resolveOrphans = function resolveOrphans(tx, callback, force)
 
 Mempool.prototype.removeOrphan = function removeOrphan(tx, callback) {
   var self = this;
-  var batch, prevout, hash;
+  var prevout, hash;
 
   function getOrphan(tx, callback) {
     if (typeof tx === 'string')
@@ -1245,14 +1159,10 @@ Mempool.prototype.removeOrphan = function removeOrphan(tx, callback) {
     if (!tx)
       return callback();
 
-    batch = self.db.batch();
-
     hash = tx.hash('hex');
     prevout = tx.getPrevout();
 
-    batch.del('O/' + hash);
-
-    utils.forEach(prevout, function(prev, next) {
+    utils.forEachSerial(prevout, function(prev, next) {
       var i, p;
       self.getWaiting(prev, function(err, hashes) {
         if (err)
@@ -1266,16 +1176,11 @@ Mempool.prototype.removeOrphan = function removeOrphan(tx, callback) {
           hashes.splice(i, 1);
 
         if (hashes.length === 0) {
-          batch.del('o/' + prev);
+          delete self.waiting[prev];
           return next();
         }
 
-        p = new BufferWriter();
-
-        for (i = 0; i < hashes.length; i++)
-          p.writeHash(hashes[i]);
-
-        batch.put('o/' + prev, p.render());
+        self.waiting[prev] = hashes;
 
         next();
       });
@@ -1283,9 +1188,10 @@ Mempool.prototype.removeOrphan = function removeOrphan(tx, callback) {
       if (err)
         return callback(err);
 
-      self.orphans--;
+      delete self.orphans[hash];
+      self.totalOrphans--;
 
-      batch.write(callback);
+      callback();
     });
   });
 };