mempool: preliminary work for persistent fees.

lib/mempool/fees.js

@@ -439,8 +439,6 @@ function PolicyEstimator(network, logger) {
   this.map = {};
   this.mapSize = 0;
   this.bestHeight = 0;
-
-  this.init();
 }
 
 /**

lib/mempool/layout-browser.js

@@ -10,6 +10,7 @@ var layout = {
   binary: false,
   R: 'R',
   V: 'V',
+  F: 'F',
   e: function e(hash) {
     return 'e' + hex(hash);
   },

lib/mempool/layout.js

@@ -17,6 +17,7 @@ var layout = {
   binary: true,
   R: new Buffer([0x52]),
   V: new Buffer([0x76]),
+  F: new Buffer([0x46]),
   e: function e(hash) {
     var key = new Buffer(33);
     key[0] = 0x65;

lib/mempool/mempool.js

@@ -27,6 +27,7 @@ var Network = require('../protocol/network');
 var encoding = require('../utils/encoding');
 var layout = require('./layout');
 var LDB = require('../db/ldb');
+var Fees = require('./fees');
 var VerifyError = errors.VerifyError;
 var VerifyResult = errors.VerifyResult;
 
@@ -106,7 +107,7 @@ util.inherits(Mempool, AsyncObject);
 
 Mempool.prototype._open = co(function* open() {
   var size = (this.options.maxSize / 1024).toFixed(2);
-  var i, entries, entry;
+  var i, entries, entry, fees;
 
   yield this.chain.open();
   yield this.cache.open();
@@ -123,6 +124,17 @@ Mempool.prototype._open = co(function* open() {
       entry = entries[i];
       this.updateAncestors(entry);
     }
+
+    if (this.fees) {
+      fees = yield this.cache.getFees();
+
+      if (fees) {
+        this.fees.inject(fees);
+        this.logger.info(
+          'Loaded mempool fee data (rate=%d).',
+          this.fees.estimateFee());
+      }
+    }
   }
 
   this.logger.info('Mempool loaded (maxsize=%dkb).', size);
@@ -189,8 +201,11 @@ Mempool.prototype._addBlock = co(function* addBlock(block, txs) {
     entries.push(entry);
   }
 
-  if (this.fees)
+  if (this.fees) {
     this.fees.processBlock(block.height, entries, this.chain.synced);
+    // Note: disable for now.
+    // this.cache.writeFees(this.fees);
+  }
 
   // We need to reset the rejects filter periodically.
   // There may be a locktime in a TX that is now valid.
@@ -2299,6 +2314,7 @@ function MempoolCache(options) {
 
   this.logger = options.logger;
   this.chain = options.chain;
+  this.network = options.network;
   this.db = null;
   this.batch = null;
 
@@ -2326,6 +2342,15 @@ MempoolCache.prototype.getTip = co(function* getTip() {
   return hash.toString('hex');
 });
 
+MempoolCache.prototype.getFees = co(function* getFees() {
+  var data = yield this.db.get(layout.F);
+
+  if (!data)
+    return;
+
+  return Fees.fromRaw(data, this.network);
+});
+
 MempoolCache.prototype.getEntries = function getEntries() {
   return this.db.values({
     gte: layout.e(encoding.ZERO_HASH),
@@ -2380,6 +2405,13 @@ MempoolCache.prototype.sync = function sync(hash) {
   this.batch.put(layout.R, new Buffer(hash, 'hex'));
 };
 
+MempoolCache.prototype.writeFees = function writeFees(fees) {
+  if (!this.db)
+    return;
+
+  this.batch.put(layout.F, fees.toRaw());
+};
+
 MempoolCache.prototype.clear = function clear() {
   this.batch.clear();
   this.batch = this.db.batch();
@@ -2459,6 +2491,7 @@ MempoolCache.prototype.wipe = co(function* wipe() {
 
   batch.put(layout.V, encoding.U32(MempoolCache.VERSION));
   batch.put(layout.R, new Buffer(this.chain.tip.hash, 'hex'));
+  batch.del(layout.F);
 
   yield batch.write();
 

lib/node/fullnode.js

@@ -65,6 +65,7 @@ function FullNode(options) {
 
   // Fee estimation.
   this.fees = new Fees(this.network, this.logger);
+  this.fees.init();
 
   // Mempool needs access to the chain.
   this.mempool = new Mempool({