diff --git a/opensearch/client.go b/opensearch/client.go
index 5051407..910775a 100644
--- a/opensearch/client.go
+++ b/opensearch/client.go
@@ -76,21 +76,23 @@ func (c *Client) SendBulk(ds map[string]*LogDocument) {
 }
 
 type stringSliceReader struct {
-	src     [][]byte
-	pointer int
+	src [][]byte
 }
 
 func (b *stringSliceReader) Read(p []byte) (n int, err error) {
-	for b.pointer < len(b.src) {
-		sbt := b.src[b.pointer]
+	for len(b.src) > 0 {
+		sbt := b.src[0]
 		if len(p) < len(sbt) {
-			return
+			b.src[0] = sbt[len(p):]
+			sbt = sbt[:len(p)]
+			copy(p, sbt)
+			return n + len(sbt), nil
 		}
+
 		copy(p, sbt)
-		p = p[len(sbt):]
-		b.pointer++
 		n += len(sbt)
-		err = nil
+		p = p[len(sbt):]
+		b.src = b.src[1:]
 	}
 	err = io.EOF
 	return
@@ -134,7 +136,7 @@ func (c *Client) sendLoop(ctx context.Context) {
 				}
 			}()
 
-			reader := &stringSliceReader{src: sending, pointer: 0}
+			reader := &stringSliceReader{src: sending}
 			req := osapi.BulkReq{
 				Body:   reader,
 				Header: c.bulkHeader,