Added a block cache to speed up syncing.

lib/services/block/index.js

@@ -29,6 +29,7 @@ var BlockService = function(options) {
   this._blocksInQueue = 0;
   this._recentBlockHashesCount = options.recentBlockHashesCount || 50; // if you expect this chain to reorg deeper than 50, set this
   this._recentBlockHashes = new LRU(this._recentBlockHashesCount);
+  this._readAheadBlockCount = options.readAheadBlockCount || 2; // this is the number of blocks to direct the p2p service to read aheead
 };
 
 inherits(BlockService, BaseService);
@@ -943,13 +944,13 @@ BlockService.prototype._sync = function() {
 
   log.debug('Block Service: querying header service for next block using tip: ' + self._tip.hash);
 
-  self._header.getNextHash(self._tip, function(err, targetHash, nextHash) {
+  self._header.getEndHash(self._tip, self._readAheadBlockCount, function(err, targetHash, endHash) {
 
     if(err) {
       return self._handleError(err);
     }
 
-    if (!targetHash && !nextHash) {
+    if (!targetHash && !endHash) {
       return self.emit('synced');
     }
 
@@ -974,7 +975,7 @@ BlockService.prototype._sync = function() {
     self._p2p.getP2PBlock({
       filter: {
         startHash: self._tip.hash,
-        endHash: nextHash
+        endHash: endHash
       },
       blockHash: targetHash
     }, self._syncBlock.bind(self));

lib/services/header/index.js

@@ -852,12 +852,13 @@ HeaderService.prototype._sync = function() {
 
 };
 
-// this gets the header that is +2 places from hash or returns 0 if there is no such
-HeaderService.prototype.getNextHash = function(tip, callback) {
+HeaderService.prototype.getEndHash = function(tip, blockCount, callback) {
+
+  assert(blockCount >= 1, 'Header Service: block count to getEndHash must be at least 1.');
 
   var self = this;
 
-  var numResultsNeeded = Math.min((self._tip.height - tip.height), 2);
+  var numResultsNeeded = Math.min((self._tip.height - tip.height), blockCount + 1);
 
   if (numResultsNeeded === 0 && self._tip.hash === tip.hash) {
     return callback();
@@ -867,14 +868,14 @@ HeaderService.prototype.getNextHash = function(tip, callback) {
     return callback(new Error('Header Service: block service is mis-aligned '));
   }
 
-
-  var start = self._encoding.encodeHeaderHeightKey(tip.height + 1);
-  var end = self._encoding.encodeHeaderHeightKey(tip.height + 3);
+  var startingHeight = tip.height + 1;
+  var start = self._encoding.encodeHeaderHeightKey(startingHeight);
+  var end = self._encoding.encodeHeaderHeightKey(startingHeight + blockCount);
   var results = [];
 
   var criteria = {
     gte: start,
-    lt: end
+    lte: end
   };
 
   var stream = self._db.createReadStream(criteria);
@@ -895,19 +896,18 @@ HeaderService.prototype.getNextHash = function(tip, callback) {
       return streamErr;
     }
 
-    assert(results.length === numResultsNeeded, 'GetNextHash returned incorrect number of results.');
+    assert(results.length === numResultsNeeded, 'getEndHash returned incorrect number of results.');
 
-    if (!results[1]) {
-      results[1] = 0;
-    }
+    var index = numResultsNeeded - 1;
+    var endHash =  index <= 0 || !results[index] ? 0 : results[index];
 
     if (self._slowMode) {
       return setTimeout(function() {
-        callback(null, results[0], results[1]);
+        callback(null, results[0], endHash);
       }, self._slowMode);
     }
 
-    callback(null, results[0], results[1]);
+    callback(null, results[0], endHash);
 
   });
 

lib/services/p2p/index.js

@@ -27,6 +27,10 @@ var P2P = function(options) {
   this._currentBestHeight = null;
   this._latestBits = 0x1d00ffff;
   this._outgoingTxs = LRU(100); // these are outgoing txs that are awaiting getdata messages
+  this._blockCache = options.blockCacheCount || LRU({
+    max: 10,
+    maxAge: 1000 * 60 * 5}); // keep this modest to avoid memory dumps [hash -> block]
+
 };
 
 util.inherits(P2P, BaseService);
@@ -53,8 +57,18 @@ P2P.prototype.getNumberOfPeers = function() {
 };
 
 P2P.prototype.getP2PBlock = function(opts, callback) {
+
   // opts is { filter: {<start and end hashes>}, blockHash: block hash we want }
+
   var self = this;
+
+  // do we already have this block in our cache?
+  var block = self._blockCache.get(opts.blockHash);
+
+  if (block) {
+    return callback(block);
+  }
+
   var peer = self._getPeer();
 
   var blockFilter = self._setResourceFilter(opts.filter, 'blocks');
@@ -291,6 +305,7 @@ P2P.prototype._initPubSub = function() {
 };
 
 P2P.prototype._onPeerBlock = function(peer, message) {
+  this._blockCache.set(message.block.rhash(), message.block);
   this.emit(message.block.rhash(), message.block);
   this._broadcast(this.subscriptions.block, 'p2p/block', message.block);
 };