wip

lib/services/block/index.js

@@ -26,6 +26,10 @@ var BlockService = function(options) {
   this._subscriptions.block = [];
   this._subscriptions.reorg = [];
 
+  //memory
+  this._maxMem = options.maxMemory || 1500; // in MB
+  this._deferTimeout = null;
+
   // meta is [{ chainwork: chainwork, hash: hash }]
   this._meta = [];
 
@@ -198,6 +202,9 @@ BlockService.prototype.start = function(callback) {
 };
 
 BlockService.prototype.stop = function(callback) {
+  if (this._deferTimeout) {
+    this._deferTimeout.unref();
+  }
   callback();
 };
 
@@ -663,23 +670,44 @@ BlockService.prototype._sendDelta = function() {
   if (++this._blockCount >= BlockService.MAX_BLOCKS) {
     this._latestBlockHash = this._tip.hash;
     this._blockCount = 0;
-    // this is where we ask the p2p network for more block
+    this._continueSync();
-    var self = this;
-
-    // we need a pause here before asking for more blocks so that the db work write queue,
-    // does not get too large and cause a memory issue
-    // the larger the difference between network speeds and disk i/o speeds should result in
-    // larger waits, e.g. gigabit internet speeds and a usb 2.0 5400 rpm hard disk might 10-20
-    // between each 500 block chunk
-    setTimeout(function() {
-
-      self._sync();
-
-    }, 10000);
   }
 
 };
 
+BlockService.prototype._continueSync = function() {
+  /*
+     Essentially, we have three distinct tasks taking place during a sync operation
+
+     1. receiving network data
+     2. light processing of that data (data manipulation)
+     3. writing that data to disk
+
+     Our goal: Sync as quickly as our least performant task will allow using a modest amount of memory.
+     If our network is very fast and our disk is very slow and we have very little memory to work with,
+     this is the worst case scenario. We want to defer asking the p2p service for more blocks until the
+     disk has time to process all the queued everts.
+
+     Our way of dealing with this is to review the resident set size and defer the next call to sync if
+     we are in danger of a 'JS Object Allocation Failed - Out of Memory' fault.
+
+     You can use the "maxMemory" config setting for this service to limit the amount of memory considered.
+     The default is 1.5GB of memory, max.
+
+     If we are over 95% of max memory usage, we will defer the sync until we are 95% or less.
+  */
+
+  var self = this;
+  var totalRss = process.memoryUsage().rss;
+  if ((totalRss / 1E6) / self._maxMem > 0.95) {
+    self._deferTimeout = setTimeout(function() {
+      self._continueSync();
+    }, 1000);
+    return;
+  }
+  self._sync();
+};
+
 BlockService.prototype._setListeners = function() {
 
   this._p2p.once('bestHeight', this._onBestHeight.bind(this));

lib/services/db/index.js

@@ -37,6 +37,7 @@ function DB(options) {
 
   this.subscriptions = {};
 
+  this._operationsCount = 0;
   this.GENESIS_HASH = constants.BITCOIN_GENESIS_HASH[this.node.getNetworkName()];
   this.node.on('stopping', function() {
     log.warn('Node is stopping, gently closing the database.');
@@ -158,8 +159,10 @@ DB.prototype.put = function(key, value, options) {
     return;
   }
 
+  self._operationsCount++;
   self._store.put(key, value, options, function(err) {
 
+    self._operationsCount--;
     if (err) {
       self.emit('error', err);
       return;
@@ -176,8 +179,11 @@ DB.prototype.batch = function(ops, options) {
     return;
   }
 
+  self._operationsCount += ops.length;
   self._store.batch(ops, options, function(err) {
 
+    self._operationsCount -= ops.length;
+
     if (err) {
       self.emit('error', err);
       return;
@@ -212,6 +218,7 @@ DB.prototype.createKeyStream = function(op) {
 DB.prototype.stop = function(callback) {
   var self = this;
   self._stopping = true;
+
   self.close(callback);
 };