From 497190f343abbb71294a57e1c54b3d75778788f2 Mon Sep 17 00:00:00 2001
From: Julian Kornberger <jk+github@digineo.de>
Date: Sat, 12 Mar 2016 16:27:52 +0100
Subject: [PATCH] Optimize batch insertion

---
 stats_db.go | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/stats_db.go b/stats_db.go
index d4e0793..9bfd432 100644
--- a/stats_db.go
+++ b/stats_db.go
@@ -10,7 +10,7 @@ import (
 )
 
 const (
-	saveInterval = time.Second * 5
+	batchWaiting = time.Second * 5
 )
 
 type StatsDb struct {
@@ -99,8 +99,6 @@ func (c *StatsDb) Close() {
 
 // stores data points in batches into the influxdb
 func (c *StatsDb) worker() {
-	lastSent := time.Now()
-	open := true // channel open?
 	bpConfig := client.BatchPointsConfig{
 		Database:  config.Influxdb.Database,
 		Precision: "m",
@@ -108,9 +106,10 @@ func (c *StatsDb) worker() {
 
 	var bp client.BatchPoints
 	var err error
-	var dirty bool
+	var dirty, closed bool
+	var batchStarted time.Time
 
-	for open {
+	for !closed {
 		// create new batch points?
 		if bp == nil {
 			if bp, err = client.NewBatchPoints(bpConfig); err != nil {
@@ -123,22 +122,24 @@ func (c *StatsDb) worker() {
 		case point, ok := <-c.points:
 			if ok {
 				bp.AddPoint(point)
-				dirty = true
+				if !dirty {
+					batchStarted = time.Now()
+					dirty = true
+				}
 			} else {
-				open = false
+				closed = true
 			}
 		case <-time.After(time.Second):
 			// nothing
 		}
 
 		// write batch now?
-		if dirty && (!open || lastSent.Add(saveInterval).Before(time.Now())) {
+		if (dirty && batchStarted.Add(batchWaiting).Before(time.Now())) || closed {
 			log.Println("saving", len(bp.Points()), "points")
 
 			if err = c.client.Write(bp); err != nil {
 				panic(err)
 			}
-			lastSent = time.Now()
 			dirty = false
 			bp = nil
 		}