Acquire lock before incrementing orc.nextTxnTs (dgraph-io#806)

* Acquire lock before incrementing orc.nextTxnTs Incrementing the value of db.orc.nextTxnTs without acquiring lock causes race condition. See https://teamcity.dgraph.io/viewLog.html?buildId=11417&buildTypeId=Badger_UnitTests logs
ahdong2007 · May 9, 2019 · 3374ec2 · 3374ec2
1 parent 50bef1d
commit 3374ec2
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Showing 2 changed files with 7 additions and 1 deletion.
diff --git a/db.go b/db.go
@@ -309,7 +309,7 @@ func Open(opt Options) (db *DB, err error) {
 	// In normal mode, we must update readMark so older versions of keys can be removed during
 	// compaction when run in offline mode via the flatten tool.
 	db.orc.readMark.Done(db.orc.nextTxnTs)
-	db.orc.nextTxnTs++
+	db.orc.incrementNextTs()
 
 	db.writeCh = make(chan *request, kvWriteChCapacity)
 	db.closers.writes = y.NewCloser(1)

diff --git a/txn.go b/txn.go
@@ -127,6 +127,12 @@ func (o *oracle) nextTs() uint64 {
 	return o.nextTxnTs
 }
 
+func (o *oracle) incrementNextTs() {
+	o.Lock()
+	defer o.Unlock()
+	o.nextTxnTs++
+}
+
 // Any deleted or invalid versions at or below ts would be discarded during
 // compaction to reclaim disk space in LSM tree and thence value log.
 func (o *oracle) setDiscardTs(ts uint64) {