Merge pull request #465 from 4miners/462_improve-sync-speed

Improve sync speed - Closes #462

modules/loader.js

@@ -521,12 +521,15 @@ __private.sync = function (cb) {
 // Given a list of peers (with associated blockchain height), we find a list of good peers (likely to sync with), then perform a histogram cut, removing peers far from the most common observed height. This is not as easy as it sounds, since the histogram has likely been made accross several blocks, therefore need to aggregate).
 __private.findGoodPeers = function (heights) {
 	var lastBlockHeight = modules.blocks.getLastBlock().height;
+	library.logger.trace('Good peers - received', {count: heights.length});
 
 	heights = heights.filter(function (item) {
 		// Removing unreachable peers or heights below last block height
-		return item != null || item.height >= lastBlockHeight;
+		return item != null && item.height >= lastBlockHeight;
 	});
 
+	library.logger.trace('Good peers - filtered', {count: heights.length});
+
 	// No peers found
 	if (heights.length === 0) {
 		return {height: 0, peers: []};
@@ -557,8 +560,11 @@ __private.findGoodPeers = function (heights) {
 		// Performing histogram cut of peers too far from histogram maximum
 		var peers = heights.filter(function (item) {
 			return item && Math.abs(height - item.height) < aggregation + 1;
+		}).map(function (item) {
+			return library.logic.peers.create(item);
 		});
 
+		library.logger.trace('Good peers - accepted', {count: peers.length});
 		library.logger.debug('Good peers', peers);
 
 		return {height: height, peers: peers};
@@ -576,13 +582,19 @@ Loader.prototype.getNetwork = function (cb) {
 		return setImmediate(cb, null, __private.network);
 	}
 
-	__private.network = __private.findGoodPeers(library.logic.peers.list());
+	modules.peers.list({}, function (err, peers) {
+		if (err) {
+			return setImmediate(cb, err);
+		}
 
-	if (!__private.network.peers.length) {
-		return setImmediate(cb, 'Failed to find enough good peers');
-	} else {
-		return setImmediate(cb, null, __private.network);
-	}
+		__private.network = __private.findGoodPeers(peers);
+
+		if (!__private.network.peers.length) {
+			return setImmediate(cb, 'Failed to find enough good peers');
+		} else {
+			return setImmediate(cb, null, __private.network);
+		}
+	});
 };
 
 Loader.prototype.syncing = function () {