diff --git a/lightrag/lightrag.py b/lightrag/lightrag.py
index 67f82910..03699e08 100644
--- a/lightrag/lightrag.py
+++ b/lightrag/lightrag.py
@@ -1504,6 +1504,15 @@ class LightRAG:
                                 pipeline_status["latest_message"] = log_message
                                 pipeline_status["history_messages"].append(log_message)
 
+                                # Prevent memory growth: keep only latest 5000 messages when exceeding 10000
+                                if len(pipeline_status["history_messages"]) > 10000:
+                                    pipeline_status["history_messages"] = (
+                                        pipeline_status["history_messages"][-5000:]
+                                    )
+                                    logger.info(
+                                        f"Trimming pipeline history from {len(pipeline_status['history_messages'])} to 5000 messages"
+                                    )
+
                             # Get document content from full_docs
                             content_data = await self.full_docs.get_by_id(doc_id)
                             if not content_data: