Fix resurrect timeout formula (#833)

* Fixes #827

* Updated test

Author: delvedor

lib/ConnectionPool.js

@@ -34,11 +34,7 @@ class ConnectionPool {
     this._ssl = opts.ssl
     this._agent = opts.agent
     // the resurrect timeout is 60s
-    // we multiply it by 2 because the resurrect formula is
-    // `Math.pow(resurrectTimeout * 2, deadCount -1)`
-    // and we don't need to multiply by 2
-    // the resurrectTimeout every time
-    this.resurrectTimeout = 1000 * 60 * 2
+    this.resurrectTimeout = 1000 * 60
     // number of consecutive failures after which
     // the timeout doesn't increase
     this.resurrectTimeoutCutoff = 5
@@ -94,15 +90,9 @@ class ConnectionPool {
     connection.status = Connection.statuses.DEAD
     connection.deadCount++
     // resurrectTimeout formula:
-    // `Math.pow(resurrectTimeout * 2, deadCount -1)`
-    // we don't need to multiply the resurrectTimeout by 2
-    // every time, it is cached during the initialization
-    connection.resurrectTimeout = Date.now() + Math.pow(
-      this.resurrectTimeout,
-      Math.min(
-        connection.deadCount - 1,
-        this.resurrectTimeoutCutoff
-      )
+    // `resurrectTimeout * 2 ** min(deadCount - 1, resurrectTimeoutCutoff)`
+    connection.resurrectTimeout = Date.now() + this.resurrectTimeout * Math.pow(
+      2, Math.min(connection.deadCount - 1, this.resurrectTimeoutCutoff)
     )
 
     // sort the dead list in ascending order

test/behavior/resurrect.test.js

@@ -74,7 +74,7 @@ test('Should execute the recurrect API with the ping strategy', t => {
     })
 
     q.add((q, done) => {
-      clock.tick(10)
+      clock.tick(1000 * 61)
       client.info((err, result) => {
         t.error(err)
         done()
@@ -133,15 +133,15 @@ test('Resurrect a node and handle 502/3/4 status code', t => {
     })
 
     q.add((q, done) => {
-      clock.tick(10)
+      clock.tick(1000 * 61)
       client.info((err, result) => {
         t.error(err)
         done()
       })
     })
 
     q.add((q, done) => {
-      clock.tick(150000)
+      clock.tick(1000 * 10 * 60)
       client.info((err, result) => {
         t.error(err)
         done()
@@ -194,7 +194,7 @@ test('Should execute the recurrect API with the optimistic strategy', t => {
     })
 
     q.add((q, done) => {
-      clock.tick(10)
+      clock.tick(1000 * 61)
       client.info((err, result) => {
         t.error(err)
         done()