From 75a6f605c1a4c903ec0e3f212dff3c6d54d53c9a Mon Sep 17 00:00:00 2001
From: Peter Surda <surda@economicsofbitcoin.com>
Date: Sun, 22 Oct 2017 11:32:37 +0200
Subject: [PATCH] Download optimisation

- more accurate tracking
- randomise download order
- longer cycle
---
 src/network/downloadthread.py | 25 ++++++++++++++++---------
 src/network/objectracker.py   |  3 ++-
 2 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/network/downloadthread.py b/src/network/downloadthread.py
index 98b6df05..7cbe11ad 100644
--- a/src/network/downloadthread.py
+++ b/src/network/downloadthread.py
@@ -9,9 +9,10 @@ from helper_threading import StoppableThread
 #from inventory import Inventory
 from network.connectionpool import BMConnectionPool
 import protocol
+from state import missingObjects
 
 class DownloadThread(threading.Thread, StoppableThread):
-    maxPending = 200
+    minPending = 200
     requestChunk = 1000
     requestTimeout = 60
     cleanInterval = 60
@@ -22,13 +23,18 @@ class DownloadThread(threading.Thread, StoppableThread):
         self.initStop()
         self.name = "Downloader"
         logger.info("init download thread")
-        self.pending = {}
         self.lastCleaned = time.time()
 
     def cleanPending(self):
         deadline = time.time() - DownloadThread.requestExpires
-        self.pending = {k: v for k, v in self.pending.iteritems() if v >= deadline}
-        self.lastCleaned = time.time()
+        try:
+            toDelete = [k for k, v in missingObjects.iteritems() if v < deadline]
+        except RuntimeError:
+            pass
+        else:
+            for i in toDelete:
+                del missingObjects[i]
+            self.lastCleaned = time.time()
 
     def run(self):
         while not self._stopped:
@@ -41,11 +47,12 @@ class DownloadThread(threading.Thread, StoppableThread):
                 timedOut = now - DownloadThread.requestTimeout
                 # this may take a while, but it needs a consistency so I think it's better to lock a bigger chunk
                 with i.objectsNewToMeLock:
-                    downloadPending = len(list((k for k, v in i.objectsNewToMe.iteritems() if k in self.pending and self.pending[k] > timedOut)))
-                    if downloadPending >= DownloadThread.maxPending:
+                    downloadPending = len(list((k for k, v in i.objectsNewToMe.iteritems() if k in missingObjects and missingObjects[k] > timedOut)))
+                    if downloadPending >= DownloadThread.minPending:
                         continue
                     # keys with True values in the dict
-                    request = list((k for k, v in i.objectsNewToMe.iteritems() if k not in self.pending or self.pending[k] < timedOut))
+                    request = list((k for k, v in i.objectsNewToMe.iteritems() if k not in missingObjects or missingObjects[k] < timedOut))
+                    random.shuffle(request)
                     if not request:
                         continue
                     if len(request) > DownloadThread.requestChunk - downloadPending:
@@ -53,7 +60,7 @@ class DownloadThread(threading.Thread, StoppableThread):
                     # mark them as pending
                     for k in request:
                         i.objectsNewToMe[k] = False
-                        self.pending[k] = now
+                        missingObjects[k] = now
 
                 payload = bytearray()
                 payload.extend(addresses.encodeVarint(len(request)))
@@ -65,4 +72,4 @@ class DownloadThread(threading.Thread, StoppableThread):
             if time.time() >= self.lastCleaned + DownloadThread.cleanInterval:
                 self.cleanPending()
             if not requested:
-                self.stop.wait(1)
+                self.stop.wait(5)
diff --git a/src/network/objectracker.py b/src/network/objectracker.py
index bfb75174..a86ec23f 100644
--- a/src/network/objectracker.py
+++ b/src/network/objectracker.py
@@ -83,7 +83,8 @@ class ObjectTracker(object):
         except KeyError:
             pass
         if hashId not in Inventory():
-            missingObjects[hashId] = None
+            if hashId not in missingObjects:
+                missingObjects[hashId] = time.time()
             with self.objectsNewToMeLock:
                 self.objectsNewToMe[hashId] = True
         elif hashId in Dandelion().hashMap: