wal: consolidate LogRecycler.[Set]MinRecycleLogNum

These MinRecycleLogNum and SetMinRecycleLogNum methods were only used to
ratchet the minimum log num, so this commit consolidates the two under a
RatchetMinRecycleLogNum method.

Author: jbowens

wal/failover_manager.go

@@ -526,9 +526,7 @@ func (wm *failoverManager) init(o Options, initial Logs) error {
 	}
 	wm.recycler.Init(o.MaxNumRecyclableLogs)
 	for _, ll := range initial {
-		if wm.recycler.MinRecycleLogNum() <= ll.Num {
-			wm.recycler.SetMinRecycleLogNum(ll.Num + 1)
-		}
+		wm.recycler.RatchetMinRecycleLogNum(ll.Num + 1)
 		var err error
 		wm.initialObsolete, err = appendDeletableLogs(wm.initialObsolete, ll)
 		if err != nil {

wal/failover_manager_test.go

@@ -382,7 +382,7 @@ func TestManagerFailover(t *testing.T) {
 				var b strings.Builder
 				fmt.Fprintf(&b, "%s\n", errorToStr(err))
 				if err == nil {
-					fmt.Fprintf(&b, "recycler min-log-num: %d\n", fm.recycler.MinRecycleLogNum())
+					fmt.Fprintf(&b, "recycler min-log-num: %d\n", fm.recycler.minRecycleLogNum)
 				}
 				return b.String()
 

wal/log_recycler.go

@@ -40,16 +40,12 @@ func (r *LogRecycler) Init(maxNumLogFiles int) {
 	r.limit = maxNumLogFiles
 }
 
-// MinRecycleLogNum returns the current minimum log number that is allowed to
-// be recycled.
-func (r *LogRecycler) MinRecycleLogNum() NumWAL {
-	return NumWAL(r.minRecycleLogNum)
-}
-
-// SetMinRecycleLogNum sets the minimum log number that is allowed to be
-// recycled.
-func (r *LogRecycler) SetMinRecycleLogNum(n NumWAL) {
-	r.minRecycleLogNum = base.DiskFileNum(n)
+// RatchetMinRecycleLogNum ratchets the minimum log number that is allowed to be
+// recycled to be at least as high as the given log number.
+func (r *LogRecycler) RatchetMinRecycleLogNum(n NumWAL) {
+	if num := base.DiskFileNum(n); num > r.minRecycleLogNum {
+		r.minRecycleLogNum = num
+	}
 }
 
 // Add attempts to recycle the log file specified by logInfo. Returns true if

wal/standalone_manager.go

@@ -67,9 +67,7 @@ func (m *StandaloneManager) init(o Options, initial Logs) error {
 		return err
 	}
 	for _, ll := range initial {
-		if m.recycler.MinRecycleLogNum() <= ll.Num {
-			m.recycler.SetMinRecycleLogNum(ll.Num + 1)
-		}
+		m.recycler.RatchetMinRecycleLogNum(ll.Num + 1)
 		m.initialObsolete, err = appendDeletableLogs(m.initialObsolete, ll)
 		if err != nil {
 			return closeAndReturnErr(err)