fix: Add data consistency validation to document processing pipeline

- Add _validate_and_fix_document_consistency() method to detect and fix documents with missing content in full_docs storage
- Integrate consistency check into apipeline_process_enqueue_documents() to automatically mark inconsistent documents as FAILED before processing
- Prevent processing errors caused by documents having status records but missing actual content data

lightrag/lightrag.py

@@ -1110,6 +1110,48 @@ class LightRAG:
 
         return track_id
 
+    async def _validate_and_fix_document_consistency(
+        self, to_process_docs: dict[str, DocProcessingStatus]
+    ) -> dict[str, DocProcessingStatus]:
+        """Validate and fix document data consistency"""
+        inconsistent_docs = []
+
+        for doc_id, status_doc in to_process_docs.items():
+            # Check if corresponding content exists in full_docs
+            content_data = await self.full_docs.get_by_id(doc_id)
+            if not content_data:
+                inconsistent_docs.append(doc_id)
+                logger.warning(
+                    f"Document {doc_id} has status record but missing content in full_docs"
+                )
+
+        # Mark inconsistent documents as FAILED
+        if inconsistent_docs:
+            failed_updates = {}
+            for doc_id in inconsistent_docs:
+                status_doc = to_process_docs[doc_id]
+                failed_updates[doc_id] = {
+                    "status": DocStatus.FAILED,
+                    "error_msg": "Document content not found in full_docs storage - data inconsistency detected",
+                    "content_summary": status_doc.content_summary,
+                    "content_length": status_doc.content_length,
+                    "created_at": status_doc.created_at,
+                    "updated_at": datetime.now(timezone.utc).isoformat(),
+                    "file_path": status_doc.file_path,
+                    "track_id": status_doc.track_id,
+                }
+
+            await self.doc_status.upsert(failed_updates)
+            logger.info(
+                f"Marked {len(inconsistent_docs)} inconsistent documents as FAILED"
+            )
+
+            # Remove these documents from the processing list
+            for doc_id in inconsistent_docs:
+                to_process_docs.pop(doc_id, None)
+
+        return to_process_docs
+
     async def apipeline_process_enqueue_documents(
         self,
         split_by_character: str | None = None,
@@ -1121,9 +1163,10 @@ class LightRAG:
         document status.
 
         1. Get all pending, failed, and abnormally terminated processing documents.
-        2. Split document content into chunks
+        2. Validate document data consistency and fix any issues
-        3. Process each chunk for entity and relation extraction
+        3. Split document content into chunks
-        4. Update the document status
+        4. Process each chunk for entity and relation extraction
+        5. Update the document status
         """
 
         # Get pipeline status shared data and lock
@@ -1149,6 +1192,15 @@ class LightRAG:
                     logger.info("No documents to process")
                     return
 
+                # Validate document data consistency and fix any issues
+                to_process_docs = await self._validate_and_fix_document_consistency(
+                    to_process_docs
+                )
+
+                if not to_process_docs:
+                    logger.info("No valid documents to process after consistency check")
+                    return
+
                 pipeline_status.update(
                     {
                         "busy": True,