save source buffer index start for log files

weed/util/log_buffer/log_buffer.go

@@ -63,6 +63,7 @@ func NewLogBuffer(name string, flushInterval time.Duration, flushFn LogFlushFunc
 		notifyFn:       notifyFn,
 		flushChan:      make(chan *dataToFlush, 256),
 		isStopping:     new(atomic.Bool),
+		batchIndex:     time.Now().UnixNano(), // Initialize with process start time for uniqueness
 	}
 	go lb.loopFlush()
 	go lb.loopInterval()
@@ -343,6 +344,20 @@ func (logBuffer *LogBuffer) ReleaseMemory(b *bytes.Buffer) {
 	bufferPool.Put(b)
 }
 
+// GetName returns the log buffer name for metadata tracking
+func (logBuffer *LogBuffer) GetName() string {
+	logBuffer.RLock()
+	defer logBuffer.RUnlock()
+	return logBuffer.name
+}
+
+// GetBatchIndex returns the current batch index for metadata tracking
+func (logBuffer *LogBuffer) GetBatchIndex() int64 {
+	logBuffer.RLock()
+	defer logBuffer.RUnlock()
+	return logBuffer.batchIndex
+}
+
 var bufferPool = sync.Pool{
 	New: func() interface{} {
 		return new(bytes.Buffer)