Event replay and cleanup

pkg/docbuf/docbuf.go

@@ -263,6 +263,11 @@ func NewDocumentBuffer(
  * If cache is full oldest document is written to backing writer.
  */
 func (b *DocBuf) Push(doc string) error {
+	if b.cacheSize == 0 {
+		b.writeToBackingStore(doc)
+		return nil
+	}
+
 	if len(b.cache) >= b.cacheSize {
 		if err := b.demote(); err != nil {
 			return err
@@ -280,6 +285,14 @@ func (b *DocBuf) Push(doc string) error {
  * out of the backing ReaderWriter.
  */
 func (b *DocBuf) Pop() (string, error) {
+	if b.cacheSize == 0 {
+		d, e := b.readDocumentsFromDisk(1, true, false)
+		if len(d) > 0 {
+			return d[0], e
+		}
+		return "", e
+	}
+
 	if len(b.cache) < 1 {
 		if err := b.promote(true); err != nil {
 			return "", err