From c3943c0111bfb5c744095ae47b3341e62bb9790e Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 21 Jan 2016 01:50:22 -0800
Subject: [PATCH] chaindb. avoid buffered writes.

---
 lib/bcoin/chain.js | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/lib/bcoin/chain.js b/lib/bcoin/chain.js
index 5ea973c8..63164e89 100644
--- a/lib/bcoin/chain.js
+++ b/lib/bcoin/chain.js
@@ -25,15 +25,18 @@ function Chain(options) {
 
   EventEmitter.call(this);
 
-  this.options = options || {};
-  this.prefix = 'bt/chain/';
-  this.storage = this.options.storage;
-  this.strict = this.options.strict || false;
-  this.db = new ChainDB(this);
+  if (!options)
+    options = {};
+
+  this.options = options;
 
   if (this.options.debug)
     bcoin.debug = this.options.debug;
 
+  this.db = new ChainDB(this);
+  this.heightLookup = {};
+  this.request = new utils.RequestCache();
+  this.loading = false;
   this.tip = null;
 
   this.orphan = {
@@ -43,10 +46,6 @@ function Chain(options) {
     size: 0
   };
 
-  this.heightLookup = {};
-
-  this.request = new utils.RequestCache();
-
   this._addIndex(ChainBlock.fromJSON(this, {
     hash: network.genesis.hash,
     version: network.genesis.version,
@@ -60,7 +59,6 @@ function Chain(options) {
 
   Chain.global = this;
 
-  this.loading = false;
   this._init();
 }
 
@@ -711,6 +709,7 @@ function ChainDB(chain, options) {
   this.tip = -1;
   this.size = 0;
   this.fd = null;
+  this._writing = 0;
 
   // Need to cache up to the retarget interval
   // if we're going to be checking the damn
@@ -768,6 +767,7 @@ ChainDB.prototype.count = function count() {
 };
 
 ChainDB.prototype.cache = function cache(entry) {
+  assert.equal(this.tip, this.count() - 1);
   if (entry.height > this.tip) {
     this.tip = entry.height;
     delete this._cache[entry.height - this._cacheWindow];
@@ -828,11 +828,16 @@ ChainDB.prototype.save = function save(entry, callback) {
   // Speed up writes by doing them asynchronously
   // and keeping the data to be written in memory.
   this._queue[entry.height] = entry;
+  this._writing++;
 
   // Write asynchronously to the db.
   raw = entry.toRaw();
   offset = entry.height * BLOCK_SIZE;
 
+  // Avoid using buffered writes for now.
+  delete this._queue[entry.height];
+  return this._writeSync(raw, offset);
+
   return this._write(raw, offset, function(err, success) {
     var item = self._queue[entry.height];
 
@@ -848,6 +853,7 @@ ChainDB.prototype.save = function save(entry, callback) {
     }
 
     delete self._queue[entry.height];
+    self._writing--;
 
     if (err) {
       if (callback)
@@ -948,7 +954,7 @@ ChainDB.prototype._writeSync = function _writeSync(data, offset) {
     size -= bytes;
     offset += bytes;
     if (index === data.length) {
-      self.size += data.length;
+      this.size += data.length;
       return true;
     }
   }