From 5caab82485132370bbb7c8ca1a1f15d018d399f3 Mon Sep 17 00:00:00 2001
From: Ibrahim Jarif <ibrahim@dgraph.io>
Date: Mon, 8 Jul 2019 12:06:44 +0530
Subject: [PATCH] Fix race condition in flushDiscardStats function (#921)

A couple of builds failed on teamcity with data race error.
See https://teamcity.dgraph.io/viewLog.html?buildId=16131

This PR fixes the data race in `flushDiscardStats` function.
---
 value.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/value.go b/value.go
index 815e808b2..c01fa70e0 100644
--- a/value.go
+++ b/value.go
@@ -1396,9 +1396,13 @@ func (vlog *valueLog) updateDiscardStats(stats map[uint32]int64) error {
 
 // flushDiscardStats inserts discard stats into badger. Returns error on failure.
 func (vlog *valueLog) flushDiscardStats() error {
+	vlog.lfDiscardStats.Lock()
 	if len(vlog.lfDiscardStats.m) == 0 {
+		vlog.lfDiscardStats.Unlock()
 		return nil
 	}
+	vlog.lfDiscardStats.Unlock()
+
 	entries := []*Entry{{
 		Key:   y.KeyWithTs(lfDiscardStatsKey, 1),
 		Value: vlog.encodedDiscardStats(),