at max look at 64 ranges (random) on each tick (#594)

Author: mafintosh

lib/replicator.js

@@ -38,6 +38,8 @@ const DEFAULT_SEGMENT_SIZE = 256 * 1024 * 8 // 256 KiB in bits
 const NOT_DOWNLOADING_SLACK = 20000 + (Math.random() * 20000) | 0
 const MAX_PEERS_UPGRADE = 3
 
+const MAX_RANGES = 64
+
 const PRIORITY = {
   NORMAL: 0,
   HIGH: 1,
@@ -1623,11 +1625,18 @@ module.exports = class Replicator {
 
     const ref = r.attach(session)
 
-    this._ranges.push(r)
-
     // Trigger this to see if this is already resolved...
     // Also auto compresses the range based on local bitfield
-    this._updateNonPrimary(true)
+    clampRange(this.core, r)
+
+    this._ranges.push(r)
+
+    if (r.end !== -1 && r.start >= r.end) {
+      this._resolveRangeRequest(r, this._ranges.length - 1)
+      return ref
+    }
+
+    this.updateAll()
 
     return ref
   }
@@ -1899,13 +1908,16 @@ module.exports = class Replicator {
   async _updateNonPrimary (updateAll) {
     // Check if running, if so skip it and the running one will issue another update for us (debounce)
     while (++this._updatesPending === 1) {
-      for (let i = 0; i < this._ranges.length; i++) {
+      let len = Math.min(MAX_RANGES, this._ranges.length)
+
+      for (let i = 0; i < len; i++) {
         const r = this._ranges[i]
 
         clampRange(this.core, r)
 
         if (r.end !== -1 && r.start >= r.end) {
           this._resolveRangeRequest(r, i--)
+          if (len > this._ranges.length) len--
         }
       }
 
@@ -2187,11 +2199,13 @@ module.exports = class Replicator {
     }
 
     const ranges = new RandomIterator(this._ranges)
+    let tried = 0
 
     for (const r of ranges) {
       if (peer._requestRange(r) === true) {
         return true
       }
+      if (++tried >= MAX_RANGES) break
     }
 
     // Iterate from newest fork to oldest fork...