feat: implement Summary Index feature.

api/controllers/console/datasets/datasets.py

@@ -146,6 +146,7 @@ class DatasetUpdatePayload(BaseModel):
     embedding_model: str | None = None
     embedding_model_provider: str | None = None
     retrieval_model: dict[str, Any] | None = None
+    summary_index_setting: dict[str, Any] | None = None
     partial_member_list: list[str] | None = None
     external_retrieval_model: dict[str, Any] | None = None
     external_knowledge_id: str | None = None

api/controllers/console/datasets/datasets_document.py

@@ -39,9 +39,10 @@ from fields.document_fields import (
 from libs.datetime_utils import naive_utc_now
 from libs.login import current_account_with_tenant, login_required
 from models import DatasetProcessRule, Document, DocumentSegment, UploadFile
-from models.dataset import DocumentPipelineExecutionLog
+from models.dataset import DocumentPipelineExecutionLog, DocumentSegmentSummary
 from services.dataset_service import DatasetService, DocumentService
 from services.entities.knowledge_entities.knowledge_entities import KnowledgeConfig, ProcessRule, RetrievalModel
+from tasks.generate_summary_index_task import generate_summary_index_task
 
 from ..app.error import (
     ProviderModelCurrentlyNotSupportError,
@@ -104,6 +105,10 @@ class DocumentRenamePayload(BaseModel):
     name: str
 
 
+class GenerateSummaryPayload(BaseModel):
+    document_list: list[str]
+
+
 register_schema_models(
     console_ns,
     KnowledgeConfig,
@@ -111,6 +116,7 @@ register_schema_models(
     RetrievalModel,
     DocumentRetryPayload,
     DocumentRenamePayload,
+    GenerateSummaryPayload,
 )
 
 
@@ -295,6 +301,97 @@ class DatasetDocumentListApi(Resource):
 
         paginated_documents = db.paginate(select=query, page=page, per_page=limit, max_per_page=100, error_out=False)
         documents = paginated_documents.items
+        
+        # Check if dataset has summary index enabled
+        has_summary_index = (
+            dataset.summary_index_setting
+            and dataset.summary_index_setting.get("enable") is True
+        )
+        
+        # Filter documents that need summary calculation
+        documents_need_summary = [doc for doc in documents if doc.need_summary is True]
+        document_ids_need_summary = [str(doc.id) for doc in documents_need_summary]
+        
+        # Calculate summary_index_status for documents that need summary (only if dataset summary index is enabled)
+        summary_status_map = {}
+        if has_summary_index and document_ids_need_summary:
+            # Get all segments for these documents (excluding qa_model and re_segment)
+            segments = (
+                db.session.query(DocumentSegment.id, DocumentSegment.document_id)
+                .where(
+                    DocumentSegment.document_id.in_(document_ids_need_summary),
+                    DocumentSegment.status != "re_segment",
+                    DocumentSegment.tenant_id == current_tenant_id,
+                )
+                .all()
+            )
+            
+            # Group segments by document_id
+            document_segments_map = {}
+            for segment in segments:
+                doc_id = str(segment.document_id)
+                if doc_id not in document_segments_map:
+                    document_segments_map[doc_id] = []
+                document_segments_map[doc_id].append(segment.id)
+            
+            # Get all summary records for these segments
+            all_segment_ids = [seg.id for seg in segments]
+            summaries = {}
+            if all_segment_ids:
+                summary_records = (
+                    db.session.query(DocumentSegmentSummary)
+                    .where(
+                        DocumentSegmentSummary.chunk_id.in_(all_segment_ids),
+                        DocumentSegmentSummary.dataset_id == dataset_id,
+                        DocumentSegmentSummary.enabled == True,  # Only count enabled summaries
+                    )
+                    .all()
+                )
+                summaries = {summary.chunk_id: summary.status for summary in summary_records}
+            
+            # Calculate summary_index_status for each document
+            for doc_id in document_ids_need_summary:
+                segment_ids = document_segments_map.get(doc_id, [])
+                if not segment_ids:
+                    # No segments, status is "GENERATING" (waiting to generate)
+                    summary_status_map[doc_id] = "GENERATING"
+                    continue
+                
+                # Count summary statuses for this document's segments
+                status_counts = {"completed": 0, "generating": 0, "error": 0, "not_started": 0}
+                for segment_id in segment_ids:
+                    status = summaries.get(segment_id, "not_started")
+                    if status in status_counts:
+                        status_counts[status] += 1
+                    else:
+                        status_counts["not_started"] += 1
+                
+                total_segments = len(segment_ids)
+                completed_count = status_counts["completed"]
+                generating_count = status_counts["generating"]
+                error_count = status_counts["error"]
+                
+                # Determine overall status (only three states: GENERATING, COMPLETED, ERROR)
+                if completed_count == total_segments:
+                    summary_status_map[doc_id] = "COMPLETED"
+                elif error_count > 0:
+                    # Has errors (even if some are completed or generating)
+                    summary_status_map[doc_id] = "ERROR"
+                elif generating_count > 0 or status_counts["not_started"] > 0:
+                    # Still generating or not started
+                    summary_status_map[doc_id] = "GENERATING"
+                else:
+                    # Default to generating
+                    summary_status_map[doc_id] = "GENERATING"
+        
+        # Add summary_index_status to each document
+        for document in documents:
+            if has_summary_index and document.need_summary is True:
+                document.summary_index_status = summary_status_map.get(str(document.id), "GENERATING")
+            else:
+                # Return null if summary index is not enabled or document doesn't need summary
+                document.summary_index_status = None
+        
         if fetch:
             for document in documents:
                 completed_segments = (
@@ -393,6 +490,7 @@ class DatasetDocumentListApi(Resource):
         return {"result": "success"}, 204
 
 
+
 @console_ns.route("/datasets/init")
 class DatasetInitApi(Resource):
     @console_ns.doc("init_dataset")
@@ -780,6 +878,7 @@ class DocumentApi(DocumentResource):
                 "display_status": document.display_status,
                 "doc_form": document.doc_form,
                 "doc_language": document.doc_language,
+                "need_summary": document.need_summary if document.need_summary is not None else False,
             }
         else:
             dataset_process_rules = DatasetService.get_process_rules(dataset_id)
@@ -815,6 +914,7 @@ class DocumentApi(DocumentResource):
                 "display_status": document.display_status,
                 "doc_form": document.doc_form,
                 "doc_language": document.doc_language,
+                "need_summary": document.need_summary if document.need_summary is not None else False,
             }
 
         return response, 200
@@ -1182,3 +1282,211 @@ class DocumentPipelineExecutionLogApi(DocumentResource):
             "input_data": log.input_data,
             "datasource_node_id": log.datasource_node_id,
         }, 200
+
+
+@console_ns.route("/datasets/<uuid:dataset_id>/documents/generate-summary")
+class DocumentGenerateSummaryApi(Resource):
+    @console_ns.doc("generate_summary_for_documents")
+    @console_ns.doc(description="Generate summary index for documents")
+    @console_ns.doc(params={"dataset_id": "Dataset ID"})
+    @console_ns.expect(console_ns.models[GenerateSummaryPayload.__name__])
+    @console_ns.response(200, "Summary generation started successfully")
+    @console_ns.response(400, "Invalid request or dataset configuration")
+    @console_ns.response(403, "Permission denied")
+    @console_ns.response(404, "Dataset not found")
+    @setup_required
+    @login_required
+    @account_initialization_required
+    @cloud_edition_billing_rate_limit_check("knowledge")
+    def post(self, dataset_id):
+        """
+        Generate summary index for specified documents.
+        
+        This endpoint checks if the dataset configuration supports summary generation
+        (indexing_technique must be 'high_quality' and summary_index_setting.enable must be true),
+        then asynchronously generates summary indexes for the provided documents.
+        """
+        current_user, _ = current_account_with_tenant()
+        dataset_id = str(dataset_id)
+        
+        # Get dataset
+        dataset = DatasetService.get_dataset(dataset_id)
+        if not dataset:
+            raise NotFound("Dataset not found.")
+        
+        # Check permissions
+        if not current_user.is_dataset_editor:
+            raise Forbidden()
+        
+        try:
+            DatasetService.check_dataset_permission(dataset, current_user)
+        except services.errors.account.NoPermissionError as e:
+            raise Forbidden(str(e))
+        
+        # Validate request payload
+        payload = GenerateSummaryPayload.model_validate(console_ns.payload or {})
+        document_list = payload.document_list
+        
+        if not document_list:
+            raise ValueError("document_list cannot be empty.")
+        
+        # Check if dataset configuration supports summary generation
+        if dataset.indexing_technique != "high_quality":
+            raise ValueError(
+                f"Summary generation is only available for 'high_quality' indexing technique. "
+                f"Current indexing technique: {dataset.indexing_technique}"
+            )
+        
+        summary_index_setting = dataset.summary_index_setting
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            raise ValueError(
+                "Summary index is not enabled for this dataset. "
+                "Please enable it in the dataset settings."
+            )
+        
+        # Verify all documents exist and belong to the dataset
+        documents = (
+            db.session.query(Document)
+            .filter(
+                Document.id.in_(document_list),
+                Document.dataset_id == dataset_id,
+            )
+            .all()
+        )
+        
+        if len(documents) != len(document_list):
+            found_ids = {doc.id for doc in documents}
+            missing_ids = set(document_list) - found_ids
+            raise NotFound(f"Some documents not found: {list(missing_ids)}")
+        
+        # Dispatch async tasks for each document
+        for document in documents:
+            # Skip qa_model documents as they don't generate summaries
+            if document.doc_form == "qa_model":
+                logger.info(
+                    f"Skipping summary generation for qa_model document {document.id}"
+                )
+                continue
+            
+            # Dispatch async task
+            generate_summary_index_task(dataset_id, document.id)
+            logger.info(
+                f"Dispatched summary generation task for document {document.id} in dataset {dataset_id}"
+            )
+        
+        return {"result": "success"}, 200
+
+
+@console_ns.route("/datasets/<uuid:dataset_id>/documents/<uuid:document_id>/summary-status")
+class DocumentSummaryStatusApi(DocumentResource):
+    @console_ns.doc("get_document_summary_status")
+    @console_ns.doc(description="Get summary index generation status for a document")
+    @console_ns.doc(params={"dataset_id": "Dataset ID", "document_id": "Document ID"})
+    @console_ns.response(200, "Summary status retrieved successfully")
+    @console_ns.response(404, "Document not found")
+    @setup_required
+    @login_required
+    @account_initialization_required
+    def get(self, dataset_id, document_id):
+        """
+        Get summary index generation status for a document.
+        
+        Returns:
+        - total_segments: Total number of segments in the document
+        - summary_status: Dictionary with status counts
+          - completed: Number of summaries completed
+          - generating: Number of summaries being generated
+          - error: Number of summaries with errors
+          - not_started: Number of segments without summary records
+        - summaries: List of summary records with status and content preview
+        """
+        current_user, _ = current_account_with_tenant()
+        dataset_id = str(dataset_id)
+        document_id = str(document_id)
+        
+        # Get document
+        document = self.get_document(dataset_id, document_id)
+        
+        # Get dataset
+        dataset = DatasetService.get_dataset(dataset_id)
+        if not dataset:
+            raise NotFound("Dataset not found.")
+        
+        # Check permissions
+        try:
+            DatasetService.check_dataset_permission(dataset, current_user)
+        except services.errors.account.NoPermissionError as e:
+            raise Forbidden(str(e))
+        
+        # Get all segments for this document
+        segments = (
+            db.session.query(DocumentSegment)
+            .filter(
+                DocumentSegment.document_id == document_id,
+                DocumentSegment.dataset_id == dataset_id,
+                DocumentSegment.status == "completed",
+                DocumentSegment.enabled == True,
+            )
+            .all()
+        )
+        
+        total_segments = len(segments)
+        
+        # Get all summary records for these segments
+        segment_ids = [segment.id for segment in segments]
+        summaries = []
+        if segment_ids:
+            summaries = (
+                db.session.query(DocumentSegmentSummary)
+                .filter(
+                    DocumentSegmentSummary.document_id == document_id,
+                    DocumentSegmentSummary.dataset_id == dataset_id,
+                    DocumentSegmentSummary.chunk_id.in_(segment_ids),
+                    DocumentSegmentSummary.enabled == True,  # Only return enabled summaries
+                )
+                .all()
+            )
+        
+        # Create a mapping of chunk_id to summary
+        summary_map = {summary.chunk_id: summary for summary in summaries}
+        
+        # Count statuses
+        status_counts = {
+            "completed": 0,
+            "generating": 0,
+            "error": 0,
+            "not_started": 0,
+        }
+        
+        summary_list = []
+        for segment in segments:
+            summary = summary_map.get(segment.id)
+            if summary:
+                status = summary.status
+                status_counts[status] = status_counts.get(status, 0) + 1
+                summary_list.append({
+                    "segment_id": segment.id,
+                    "segment_position": segment.position,
+                    "status": summary.status,
+                    "summary_preview": summary.summary_content[:100] + "..." if summary.summary_content and len(summary.summary_content) > 100 else summary.summary_content,
+                    "error": summary.error,
+                    "created_at": int(summary.created_at.timestamp()) if summary.created_at else None,
+                    "updated_at": int(summary.updated_at.timestamp()) if summary.updated_at else None,
+                })
+            else:
+                status_counts["not_started"] += 1
+                summary_list.append({
+                    "segment_id": segment.id,
+                    "segment_position": segment.position,
+                    "status": "not_started",
+                    "summary_preview": None,
+                    "error": None,
+                    "created_at": None,
+                    "updated_at": None,
+                })
+        
+        return {
+            "total_segments": total_segments,
+            "summary_status": status_counts,
+            "summaries": summary_list,
+        }, 200

api/controllers/console/datasets/datasets_segments.py

@@ -29,7 +29,7 @@ from extensions.ext_database import db
 from extensions.ext_redis import redis_client
 from fields.segment_fields import child_chunk_fields, segment_fields
 from libs.login import current_account_with_tenant, login_required
-from models.dataset import ChildChunk, DocumentSegment
+from models.dataset import ChildChunk, DocumentSegment, DocumentSegmentSummary
 from models.model import UploadFile
 from services.dataset_service import DatasetService, DocumentService, SegmentService
 from services.entities.knowledge_entities.knowledge_entities import ChildChunkUpdateArgs, SegmentUpdateArgs
@@ -38,6 +38,23 @@ from services.errors.chunk import ChildChunkIndexingError as ChildChunkIndexingS
 from tasks.batch_create_segment_to_index_task import batch_create_segment_to_index_task
 
 
+def _get_segment_with_summary(segment, dataset_id):
+    """Helper function to marshal segment and add summary information."""
+    segment_dict = marshal(segment, segment_fields)
+    # Query summary for this segment (only enabled summaries)
+    summary = (
+        db.session.query(DocumentSegmentSummary)
+        .where(
+            DocumentSegmentSummary.chunk_id == segment.id,
+            DocumentSegmentSummary.dataset_id == dataset_id,
+            DocumentSegmentSummary.enabled == True,  # Only return enabled summaries
+        )
+        .first()
+    )
+    segment_dict["summary"] = summary.summary_content if summary else None
+    return segment_dict
+
+
 class SegmentListQuery(BaseModel):
     limit: int = Field(default=20, ge=1, le=100)
     status: list[str] = Field(default_factory=list)
@@ -60,6 +77,7 @@ class SegmentUpdatePayload(BaseModel):
     keywords: list[str] | None = None
     regenerate_child_chunks: bool = False
     attachment_ids: list[str] | None = None
+    summary: str | None = None  # Summary content for summary index
 
 
 class BatchImportPayload(BaseModel):
@@ -153,8 +171,34 @@ class DatasetDocumentSegmentListApi(Resource):
 
         segments = db.paginate(select=query, page=page, per_page=limit, max_per_page=100, error_out=False)
 
+        # Query summaries for all segments in this page (batch query for efficiency)
+        segment_ids = [segment.id for segment in segments.items]
+        summaries = {}
+        if segment_ids:
+            summary_records = (
+                db.session.query(DocumentSegmentSummary)
+                .where(
+                    DocumentSegmentSummary.chunk_id.in_(segment_ids),
+                    DocumentSegmentSummary.dataset_id == dataset_id,
+                )
+                .all()
+            )
+            # Only include enabled summaries
+            summaries = {
+                summary.chunk_id: summary.summary_content 
+                for summary in summary_records 
+                if summary.enabled is True
+            }
+
+        # Add summary to each segment
+        segments_with_summary = []
+        for segment in segments.items:
+            segment_dict = marshal(segment, segment_fields)
+            segment_dict["summary"] = summaries.get(segment.id)
+            segments_with_summary.append(segment_dict)
+
         response = {
-            "data": marshal(segments.items, segment_fields),
+            "data": segments_with_summary,
             "limit": limit,
             "total": segments.total,
             "total_pages": segments.pages,
@@ -300,7 +344,7 @@ class DatasetDocumentSegmentAddApi(Resource):
         payload_dict = payload.model_dump(exclude_none=True)
         SegmentService.segment_create_args_validate(payload_dict, document)
         segment = SegmentService.create_segment(payload_dict, document, dataset)
-        return {"data": marshal(segment, segment_fields), "doc_form": document.doc_form}, 200
+        return {"data": _get_segment_with_summary(segment, dataset_id), "doc_form": document.doc_form}, 200
 
 
 @console_ns.route("/datasets/<uuid:dataset_id>/documents/<uuid:document_id>/segments/<uuid:segment_id>")
@@ -362,10 +406,12 @@ class DatasetDocumentSegmentUpdateApi(Resource):
         payload = SegmentUpdatePayload.model_validate(console_ns.payload or {})
         payload_dict = payload.model_dump(exclude_none=True)
         SegmentService.segment_create_args_validate(payload_dict, document)
+        
+        # Update segment (summary update with change detection is handled in SegmentService.update_segment)
         segment = SegmentService.update_segment(
             SegmentUpdateArgs.model_validate(payload.model_dump(exclude_none=True)), segment, document, dataset
         )
-        return {"data": marshal(segment, segment_fields), "doc_form": document.doc_form}, 200
+        return {"data": _get_segment_with_summary(segment, dataset_id), "doc_form": document.doc_form}, 200
 
     @setup_required
     @login_required

api/controllers/console/datasets/hit_testing.py

@@ -1,4 +1,4 @@
-from flask_restx import Resource
+from flask_restx import Resource, fields
 
 from controllers.common.schema import register_schema_model
 from libs.login import login_required
@@ -10,17 +10,56 @@ from ..wraps import (
     cloud_edition_billing_rate_limit_check,
     setup_required,
 )
+from fields.hit_testing_fields import (
+    child_chunk_fields,
+    document_fields,
+    files_fields,
+    hit_testing_record_fields,
+    segment_fields,
+)
 
 register_schema_model(console_ns, HitTestingPayload)
 
 
+def _get_or_create_model(model_name: str, field_def):
+    """Get or create a flask_restx model to avoid dict type issues in Swagger."""
+    existing = console_ns.models.get(model_name)
+    if existing is None:
+        existing = console_ns.model(model_name, field_def)
+    return existing
+
+
+# Register models for flask_restx to avoid dict type issues in Swagger
+document_model = _get_or_create_model("HitTestingDocument", document_fields)
+
+segment_fields_copy = segment_fields.copy()
+segment_fields_copy["document"] = fields.Nested(document_model)
+segment_model = _get_or_create_model("HitTestingSegment", segment_fields_copy)
+
+child_chunk_model = _get_or_create_model("HitTestingChildChunk", child_chunk_fields)
+files_model = _get_or_create_model("HitTestingFile", files_fields)
+
+hit_testing_record_fields_copy = hit_testing_record_fields.copy()
+hit_testing_record_fields_copy["segment"] = fields.Nested(segment_model)
+hit_testing_record_fields_copy["child_chunks"] = fields.List(fields.Nested(child_chunk_model))
+hit_testing_record_fields_copy["files"] = fields.List(fields.Nested(files_model))
+hit_testing_record_model = _get_or_create_model("HitTestingRecord", hit_testing_record_fields_copy)
+
+# Response model for hit testing API
+hit_testing_response_fields = {
+    "query": fields.String,
+    "records": fields.List(fields.Nested(hit_testing_record_model)),
+}
+hit_testing_response_model = _get_or_create_model("HitTestingResponse", hit_testing_response_fields)
+
+
 @console_ns.route("/datasets/<uuid:dataset_id>/hit-testing")
 class HitTestingApi(Resource, DatasetsHitTestingBase):
     @console_ns.doc("test_dataset_retrieval")
     @console_ns.doc(description="Test dataset knowledge retrieval")
     @console_ns.doc(params={"dataset_id": "Dataset ID"})
     @console_ns.expect(console_ns.models[HitTestingPayload.__name__])
-    @console_ns.response(200, "Hit testing completed successfully")
+    @console_ns.response(200, "Hit testing completed successfully", model=hit_testing_response_model)
     @console_ns.response(404, "Dataset not found")
     @console_ns.response(400, "Invalid parameters")
     @setup_required

api/core/entities/knowledge_entities.py

@@ -3,6 +3,7 @@ from pydantic import BaseModel, Field, field_validator
 
 class PreviewDetail(BaseModel):
     content: str
+    summary: str | None = None
     child_chunks: list[str] | None = None
 
 

api/core/indexing_runner.py

@@ -311,14 +311,18 @@ class IndexingRunner:
         qa_preview_texts: list[QAPreviewDetail] = []
 
         total_segments = 0
+        # doc_form represents the segmentation method (general, parent-child, QA)
         index_type = doc_form
         index_processor = IndexProcessorFactory(index_type).init_index_processor()
+        # one extract_setting is one source document
         for extract_setting in extract_settings:
             # extract
             processing_rule = DatasetProcessRule(
                 mode=tmp_processing_rule["mode"], rules=json.dumps(tmp_processing_rule["rules"])
             )
+            # Extract document content
             text_docs = index_processor.extract(extract_setting, process_rule_mode=tmp_processing_rule["mode"])
+            # Cleaning and segmentation
             documents = index_processor.transform(
                 text_docs,
                 current_user=None,
@@ -361,6 +365,12 @@ class IndexingRunner:
 
         if doc_form and doc_form == "qa_model":
             return IndexingEstimate(total_segments=total_segments * 20, qa_preview=qa_preview_texts, preview=[])
+
+        # Generate summary preview
+        summary_index_setting = tmp_processing_rule["summary_index_setting"] if "summary_index_setting" in tmp_processing_rule else None
+        if summary_index_setting and summary_index_setting.get('enable') and preview_texts:
+            preview_texts = index_processor.generate_summary_preview(tenant_id, preview_texts, summary_index_setting)
+
         return IndexingEstimate(total_segments=total_segments, preview=preview_texts)
 
     def _extract(

api/core/llm_generator/prompts.py

@@ -434,3 +434,6 @@ INSTRUCTION_GENERATE_TEMPLATE_PROMPT = """The output of this prompt is not as ex
 You should edit the prompt according to the IDEAL OUTPUT."""
 
 INSTRUCTION_GENERATE_TEMPLATE_CODE = """Please fix the errors in the {{#error_message#}}."""
+
+DEFAULT_GENERATOR_SUMMARY_PROMPT = """
+You are a helpful assistant that summarizes long pieces of text into concise summaries. Given the following text, generate a brief summary that captures the main points and key information. The summary should be clear, concise, and written in complete sentences. """

api/core/rag/datasource/retrieval_service.py

@@ -371,6 +371,8 @@ class RetrievalService:
             include_segment_ids = set()
             segment_child_map = {}
             segment_file_map = {}
+            segment_summary_map = {}  # Map segment_id to summary content
+            summary_segment_ids = set()  # Track segments retrieved via summary
             with Session(bind=db.engine, expire_on_commit=False) as session:
                 # Process documents
                 for document in documents:
@@ -398,13 +400,25 @@ class RetrievalService:
                                 attachment_info = attachment_info_dict["attachment_info"]
                                 segment_id = attachment_info_dict["segment_id"]
                         else:
-                            child_index_node_id = document.metadata.get("doc_id")
-                            child_chunk_stmt = select(ChildChunk).where(ChildChunk.index_node_id == child_index_node_id)
-                            child_chunk = session.scalar(child_chunk_stmt)
+                            # Check if this is a summary document
+                            is_summary = document.metadata.get("is_summary", False)
+                            if is_summary:
+                                # For summary documents, find the original chunk via original_chunk_id
+                                original_chunk_id = document.metadata.get("original_chunk_id")
+                                if not original_chunk_id:
+                                    continue
+                                segment_id = original_chunk_id
+                                # Track that this segment was retrieved via summary
+                                summary_segment_ids.add(segment_id)
+                            else:
+                                # For normal documents, find by child chunk index_node_id
+                                child_index_node_id = document.metadata.get("doc_id")
+                                child_chunk_stmt = select(ChildChunk).where(ChildChunk.index_node_id == child_index_node_id)
+                                child_chunk = session.scalar(child_chunk_stmt)
 
-                            if not child_chunk:
-                                continue
-                            segment_id = child_chunk.segment_id
+                                if not child_chunk:
+                                    continue
+                                segment_id = child_chunk.segment_id
 
                         if not segment_id:
                             continue
@@ -489,16 +503,34 @@ class RetrievalService:
                                 if segment:
                                     segment_file_map[segment.id] = [attachment_info]
                         else:
-                            index_node_id = document.metadata.get("doc_id")
-                            if not index_node_id:
-                                continue
-                            document_segment_stmt = select(DocumentSegment).where(
-                                DocumentSegment.dataset_id == dataset_document.dataset_id,
-                                DocumentSegment.enabled == True,
-                                DocumentSegment.status == "completed",
-                                DocumentSegment.index_node_id == index_node_id,
-                            )
-                            segment = session.scalar(document_segment_stmt)
+                            # Check if this is a summary document
+                            is_summary = document.metadata.get("is_summary", False)
+                            if is_summary:
+                                # For summary documents, find the original chunk via original_chunk_id
+                                original_chunk_id = document.metadata.get("original_chunk_id")
+                                if not original_chunk_id:
+                                    continue
+                                # Track that this segment was retrieved via summary
+                                summary_segment_ids.add(original_chunk_id)
+                                document_segment_stmt = select(DocumentSegment).where(
+                                    DocumentSegment.dataset_id == dataset_document.dataset_id,
+                                    DocumentSegment.enabled == True,
+                                    DocumentSegment.status == "completed",
+                                    DocumentSegment.id == original_chunk_id,
+                                )
+                                segment = session.scalar(document_segment_stmt)
+                            else:
+                                # For normal documents, find by index_node_id
+                                index_node_id = document.metadata.get("doc_id")
+                                if not index_node_id:
+                                    continue
+                                document_segment_stmt = select(DocumentSegment).where(
+                                    DocumentSegment.dataset_id == dataset_document.dataset_id,
+                                    DocumentSegment.enabled == True,
+                                    DocumentSegment.status == "completed",
+                                    DocumentSegment.index_node_id == index_node_id,
+                                )
+                                segment = session.scalar(document_segment_stmt)
 
                         if not segment:
                             continue
@@ -526,6 +558,23 @@ class RetrievalService:
                 if record["segment"].id in segment_file_map:
                     record["files"] = segment_file_map[record["segment"].id]  # type: ignore[assignment]
 
+            # Batch query summaries for segments retrieved via summary (only enabled summaries)
+            if summary_segment_ids:
+                from models.dataset import DocumentSegmentSummary
+
+                summaries = (
+                    session.query(DocumentSegmentSummary)
+                    .filter(
+                        DocumentSegmentSummary.chunk_id.in_(summary_segment_ids),
+                        DocumentSegmentSummary.status == "completed",
+                        DocumentSegmentSummary.enabled == True,  # Only retrieve enabled summaries
+                    )
+                    .all()
+                )
+                for summary in summaries:
+                    if summary.summary_content:
+                        segment_summary_map[summary.chunk_id] = summary.summary_content
+
             result = []
             for record in records:
                 # Extract segment
@@ -549,9 +598,16 @@ class RetrievalService:
                     else None
                 )
 
+                # Extract summary if this segment was retrieved via summary
+                summary_content = segment_summary_map.get(segment.id)
+
                 # Create RetrievalSegments object
                 retrieval_segment = RetrievalSegments(
-                    segment=segment, child_chunks=child_chunks, score=score, files=files
+                    segment=segment,
+                    child_chunks=child_chunks,
+                    score=score,
+                    files=files,
+                    summary=summary_content,
                 )
                 result.append(retrieval_segment)
 

api/core/rag/embedding/retrieval.py

@@ -20,3 +20,4 @@ class RetrievalSegments(BaseModel):
     child_chunks: list[RetrievalChildChunk] | None = None
     score: float | None = None
     files: list[dict[str, str | int]] | None = None
+    summary: str | None = None  # Summary content if retrieved via summary index

api/core/rag/index_processor/index_processor_base.py

@@ -13,6 +13,7 @@ from urllib.parse import unquote, urlparse
 import httpx
 
 from configs import dify_config
+from core.entities.knowledge_entities import PreviewDetail
 from core.helper import ssrf_proxy
 from core.rag.extractor.entity.extract_setting import ExtractSetting
 from core.rag.index_processor.constant.doc_type import DocType
@@ -45,6 +46,15 @@ class BaseIndexProcessor(ABC):
     def transform(self, documents: list[Document], current_user: Account | None = None, **kwargs) -> list[Document]:
         raise NotImplementedError
 
+    @abstractmethod
+    def generate_summary_preview(self, tenant_id: str, preview_texts: list[PreviewDetail], summary_index_setting: dict) -> list[PreviewDetail]:
+        """
+        For each segment in preview_texts, generate a summary using LLM and attach it to the segment.
+        The summary can be stored in a new attribute, e.g., summary.
+        This method should be implemented by subclasses.
+        """
+        raise NotImplementedError
+
     @abstractmethod
     def load(
         self,

api/core/rag/index_processor/processor/paragraph_index_processor.py

@@ -1,9 +1,13 @@
 """Paragraph index processor."""
 
+import logging
 import uuid
 from collections.abc import Mapping
 from typing import Any
 
+logger = logging.getLogger(__name__)
+
+from core.entities.knowledge_entities import PreviewDetail
 from core.rag.cleaner.clean_processor import CleanProcessor
 from core.rag.datasource.keyword.keyword_factory import Keyword
 from core.rag.datasource.retrieval_service import RetrievalService
@@ -17,12 +21,19 @@ from core.rag.index_processor.index_processor_base import BaseIndexProcessor
 from core.rag.models.document import AttachmentDocument, Document, MultimodalGeneralStructureChunk
 from core.rag.retrieval.retrieval_methods import RetrievalMethod
 from core.tools.utils.text_processing_utils import remove_leading_symbols
+from extensions.ext_database import db
 from libs import helper
 from models.account import Account
-from models.dataset import Dataset, DatasetProcessRule
+from models.dataset import Dataset, DatasetProcessRule, DocumentSegment
 from models.dataset import Document as DatasetDocument
 from services.account_service import AccountService
 from services.entities.knowledge_entities.knowledge_entities import Rule
+from services.summary_index_service import SummaryIndexService
+from core.llm_generator.prompts import DEFAULT_GENERATOR_SUMMARY_PROMPT
+from core.model_runtime.entities.message_entities import UserPromptMessage
+from core.model_runtime.entities.model_entities import ModelType
+from core.provider_manager import ProviderManager
+from core.model_manager import ModelInstance
 
 
 class ParagraphIndexProcessor(BaseIndexProcessor):
@@ -108,6 +119,29 @@ class ParagraphIndexProcessor(BaseIndexProcessor):
                 keyword.add_texts(documents)
 
     def clean(self, dataset: Dataset, node_ids: list[str] | None, with_keywords: bool = True, **kwargs):
+        # Note: Summary indexes are now disabled (not deleted) when segments are disabled.
+        # This method is called for actual deletion scenarios (e.g., when segment is deleted).
+        # For disable operations, disable_summaries_for_segments is called directly in the task.
+        # Only delete summaries if explicitly requested (e.g., when segment is actually deleted)
+        delete_summaries = kwargs.get("delete_summaries", False)
+        if delete_summaries:
+            if node_ids:
+                # Find segments by index_node_id
+                segments = (
+                    db.session.query(DocumentSegment)
+                    .filter(
+                        DocumentSegment.dataset_id == dataset.id,
+                        DocumentSegment.index_node_id.in_(node_ids),
+                    )
+                    .all()
+                )
+                segment_ids = [segment.id for segment in segments]
+                if segment_ids:
+                    SummaryIndexService.delete_summaries_for_segments(dataset, segment_ids)
+            else:
+                # Delete all summaries for the dataset
+                SummaryIndexService.delete_summaries_for_segments(dataset, None)
+
         if dataset.indexing_technique == "high_quality":
             vector = Vector(dataset)
             if node_ids:
@@ -227,3 +261,70 @@ class ParagraphIndexProcessor(BaseIndexProcessor):
             }
         else:
             raise ValueError("Chunks is not a list")
+
+    def generate_summary_preview(self, tenant_id: str, preview_texts: list[PreviewDetail], summary_index_setting: dict) -> list[PreviewDetail]:
+        """
+        For each segment, concurrently call generate_summary to generate a summary
+        and write it to the summary attribute of PreviewDetail.
+        """
+        import concurrent.futures
+        from flask import current_app
+
+        # Capture Flask app context for worker threads
+        flask_app = None
+        try:
+            flask_app = current_app._get_current_object()  # type: ignore
+        except RuntimeError:
+            logger.warning("No Flask application context available, summary generation may fail")
+
+        def process(preview: PreviewDetail) -> None:
+            """Generate summary for a single preview item."""
+            try:
+                if flask_app:
+                    # Ensure Flask app context in worker thread
+                    with flask_app.app_context():
+                        summary = self.generate_summary(tenant_id, preview.content, summary_index_setting)
+                        preview.summary = summary
+                else:
+                    # Fallback: try without app context (may fail)
+                    summary = self.generate_summary(tenant_id, preview.content, summary_index_setting)
+                    preview.summary = summary
+            except Exception as e:
+                logger.error(f"Failed to generate summary for preview: {str(e)}")
+                # Don't fail the entire preview if summary generation fails
+                preview.summary = None
+
+        with concurrent.futures.ThreadPoolExecutor() as executor:
+            list(executor.map(process, preview_texts))
+        return preview_texts
+
+    @staticmethod
+    def generate_summary(tenant_id: str, text: str, summary_index_setting: dict = None) -> str:
+        """
+        Generate summary for the given text using ModelInstance.invoke_llm and the default or custom summary prompt.
+        """
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            raise ValueError("summary_index_setting is required and must be enabled to generate summary.")
+
+        model_name = summary_index_setting.get("model_name")
+        model_provider_name = summary_index_setting.get("model_provider_name")
+        summary_prompt = summary_index_setting.get("summary_prompt")
+
+        # Import default summary prompt
+        if not summary_prompt:
+            summary_prompt = DEFAULT_GENERATOR_SUMMARY_PROMPT
+
+        prompt = f"{summary_prompt}\n{text}"
+
+        provider_manager = ProviderManager()
+        provider_model_bundle = provider_manager.get_provider_model_bundle(tenant_id, model_provider_name, ModelType.LLM)
+        model_instance = ModelInstance(provider_model_bundle, model_name)
+        prompt_messages = [UserPromptMessage(content=prompt)]
+
+        result = model_instance.invoke_llm(
+            prompt_messages=prompt_messages,
+            model_parameters={},
+            stream=False
+        )
+
+        return getattr(result.message, "content", "")

api/core/rag/index_processor/processor/parent_child_index_processor.py

@@ -25,6 +25,7 @@ from models.dataset import ChildChunk, Dataset, DatasetProcessRule, DocumentSegm
 from models.dataset import Document as DatasetDocument
 from services.account_service import AccountService
 from services.entities.knowledge_entities.knowledge_entities import ParentMode, Rule
+from services.summary_index_service import SummaryIndexService
 
 
 class ParentChildIndexProcessor(BaseIndexProcessor):
@@ -135,6 +136,29 @@ class ParentChildIndexProcessor(BaseIndexProcessor):
 
     def clean(self, dataset: Dataset, node_ids: list[str] | None, with_keywords: bool = True, **kwargs):
         # node_ids is segment's node_ids
+        # Note: Summary indexes are now disabled (not deleted) when segments are disabled.
+        # This method is called for actual deletion scenarios (e.g., when segment is deleted).
+        # For disable operations, disable_summaries_for_segments is called directly in the task.
+        # Only delete summaries if explicitly requested (e.g., when segment is actually deleted)
+        delete_summaries = kwargs.get("delete_summaries", False)
+        if delete_summaries:
+            if node_ids:
+                # Find segments by index_node_id
+                segments = (
+                    db.session.query(DocumentSegment)
+                    .filter(
+                        DocumentSegment.dataset_id == dataset.id,
+                        DocumentSegment.index_node_id.in_(node_ids),
+                    )
+                    .all()
+                )
+                segment_ids = [segment.id for segment in segments]
+                if segment_ids:
+                    SummaryIndexService.delete_summaries_for_segments(dataset, segment_ids)
+            else:
+                # Delete all summaries for the dataset
+                SummaryIndexService.delete_summaries_for_segments(dataset, None)
+
         if dataset.indexing_technique == "high_quality":
             delete_child_chunks = kwargs.get("delete_child_chunks") or False
             precomputed_child_node_ids = kwargs.get("precomputed_child_node_ids")

api/core/rag/index_processor/processor/qa_index_processor.py

@@ -25,9 +25,10 @@ from core.rag.retrieval.retrieval_methods import RetrievalMethod
 from core.tools.utils.text_processing_utils import remove_leading_symbols
 from libs import helper
 from models.account import Account
-from models.dataset import Dataset
+from models.dataset import Dataset, DocumentSegment
 from models.dataset import Document as DatasetDocument
 from services.entities.knowledge_entities.knowledge_entities import Rule
+from services.summary_index_service import SummaryIndexService
 
 logger = logging.getLogger(__name__)
 
@@ -144,6 +145,30 @@ class QAIndexProcessor(BaseIndexProcessor):
                 vector.create_multimodal(multimodal_documents)
 
     def clean(self, dataset: Dataset, node_ids: list[str] | None, with_keywords: bool = True, **kwargs):
+        # Note: Summary indexes are now disabled (not deleted) when segments are disabled.
+        # This method is called for actual deletion scenarios (e.g., when segment is deleted).
+        # For disable operations, disable_summaries_for_segments is called directly in the task.
+        # Note: qa_model doesn't generate summaries, but we clean them for completeness
+        # Only delete summaries if explicitly requested (e.g., when segment is actually deleted)
+        delete_summaries = kwargs.get("delete_summaries", False)
+        if delete_summaries:
+            if node_ids:
+                # Find segments by index_node_id
+                segments = (
+                    db.session.query(DocumentSegment)
+                    .filter(
+                        DocumentSegment.dataset_id == dataset.id,
+                        DocumentSegment.index_node_id.in_(node_ids),
+                    )
+                    .all()
+                )
+                segment_ids = [segment.id for segment in segments]
+                if segment_ids:
+                    SummaryIndexService.delete_summaries_for_segments(dataset, segment_ids)
+            else:
+                # Delete all summaries for the dataset
+                SummaryIndexService.delete_summaries_for_segments(dataset, None)
+
         vector = Vector(dataset)
         if node_ids:
             vector.delete_by_ids(node_ids)

api/core/workflow/nodes/document_extractor/node.py

@@ -62,6 +62,21 @@ class DocumentExtractorNode(Node[DocumentExtractorNodeData]):
         inputs = {"variable_selector": variable_selector}
         process_data = {"documents": value if isinstance(value, list) else [value]}
 
+        # Ensure storage_key is loaded for File objects
+        files_to_check = value if isinstance(value, list) else [value]
+        files_needing_storage_key = [
+            f for f in files_to_check
+            if isinstance(f, File) and not f.storage_key and f.related_id
+        ]
+        if files_needing_storage_key:
+            from factories.file_factory import StorageKeyLoader
+            from extensions.ext_database import db
+            from sqlalchemy.orm import Session
+            
+            with Session(bind=db.engine) as session:
+                storage_key_loader = StorageKeyLoader(session, tenant_id=self.tenant_id)
+                storage_key_loader.load_storage_keys(files_needing_storage_key)
+
         try:
             if isinstance(value, list):
                 extracted_text_list = list(map(_extract_text_from_file, value))
@@ -415,6 +430,15 @@ def _download_file_content(file: File) -> bytes:
             response.raise_for_status()
             return response.content
         else:
+            # Check if storage_key is set
+            if not file.storage_key:
+                raise FileDownloadError(f"File storage_key is missing for file: {file.filename}")
+            
+            # Check if file exists before downloading
+            from extensions.ext_storage import storage
+            if not storage.exists(file.storage_key):
+                raise FileDownloadError(f"File not found in storage: {file.storage_key}")
+            
             return file_manager.download(file)
     except Exception as e:
         raise FileDownloadError(f"Error downloading file: {str(e)}") from e

api/core/workflow/nodes/knowledge_index/entities.py

@@ -158,3 +158,5 @@ class KnowledgeIndexNodeData(BaseNodeData):
     type: str = "knowledge-index"
     chunk_structure: str
     index_chunk_variable_selector: list[str]
+    indexing_technique: str | None = None
+    summary_index_setting: dict | None = None

api/core/workflow/nodes/knowledge_index/knowledge_index_node.py

@@ -1,9 +1,11 @@
+import concurrent.futures
 import datetime
 import logging
 import time
 from collections.abc import Mapping
 from typing import Any
 
+from flask import current_app
 from sqlalchemy import func, select
 
 from core.app.entities.app_invoke_entities import InvokeFrom
@@ -16,7 +18,9 @@ from core.workflow.nodes.base.node import Node
 from core.workflow.nodes.base.template import Template
 from core.workflow.runtime import VariablePool
 from extensions.ext_database import db
-from models.dataset import Dataset, Document, DocumentSegment
+from models.dataset import Dataset, Document, DocumentSegment, DocumentSegmentSummary
+from services.summary_index_service import SummaryIndexService
+from tasks.generate_summary_index_task import generate_summary_index_task
 
 from .entities import KnowledgeIndexNodeData
 from .exc import (
@@ -67,7 +71,18 @@ class KnowledgeIndexNode(Node[KnowledgeIndexNodeData]):
         # index knowledge
         try:
             if is_preview:
-                outputs = self._get_preview_output(node_data.chunk_structure, chunks)
+                # Preview mode: generate summaries for chunks directly without saving to database
+                # Format preview and generate summaries on-the-fly
+                # Get indexing_technique and summary_index_setting from node_data (workflow graph config)
+                # or fallback to dataset if not available in node_data
+                indexing_technique = node_data.indexing_technique or dataset.indexing_technique
+                summary_index_setting = node_data.summary_index_setting or dataset.summary_index_setting
+                
+                outputs = self._get_preview_output_with_summaries(
+                    node_data.chunk_structure, chunks, dataset=dataset,
+                    indexing_technique=indexing_technique,
+                    summary_index_setting=summary_index_setting
+                )
                 return NodeRunResult(
                     status=WorkflowNodeExecutionStatus.SUCCEEDED,
                     inputs=variables,
@@ -163,6 +178,9 @@ class KnowledgeIndexNode(Node[KnowledgeIndexNodeData]):
 
         db.session.commit()
 
+        # Generate summary index if enabled
+        self._handle_summary_index_generation(dataset, document, variable_pool)
+
         return {
             "dataset_id": ds_id_value,
             "dataset_name": dataset_name_value,
@@ -173,9 +191,269 @@ class KnowledgeIndexNode(Node[KnowledgeIndexNodeData]):
             "display_status": "completed",
         }
 
-    def _get_preview_output(self, chunk_structure: str, chunks: Any) -> Mapping[str, Any]:
+    def _handle_summary_index_generation(
+        self,
+        dataset: Dataset,
+        document: Document,
+        variable_pool: VariablePool,
+    ) -> None:
+        """
+        Handle summary index generation based on mode (debug/preview or production).
+
+        Args:
+            dataset: Dataset containing the document
+            document: Document to generate summaries for
+            variable_pool: Variable pool to check invoke_from
+        """
+        # Only generate summary index for high_quality indexing technique
+        if dataset.indexing_technique != "high_quality":
+            return
+
+        # Check if summary index is enabled
+        summary_index_setting = dataset.summary_index_setting
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            return
+
+        # Skip qa_model documents
+        if document.doc_form == "qa_model":
+            return
+
+        # Determine if in preview/debug mode
+        invoke_from = variable_pool.get(["sys", SystemVariableKey.INVOKE_FROM])
+        is_preview = invoke_from and invoke_from.value == InvokeFrom.DEBUGGER
+
+        # Determine if only parent chunks should be processed
+        only_parent_chunks = dataset.chunk_structure == "parent_child_index"
+
+        if is_preview:
+            try:
+                # Query segments that need summary generation
+                query = db.session.query(DocumentSegment).filter_by(
+                    dataset_id=dataset.id,
+                    document_id=document.id,
+                    status="completed",
+                    enabled=True,
+                )
+                segments = query.all()
+
+                if not segments:
+                    logger.info(f"No segments found for document {document.id}")
+                    return
+
+                # Filter segments based on mode
+                segments_to_process = []
+                for segment in segments:
+                    # Skip if summary already exists
+                    existing_summary = (
+                        db.session.query(DocumentSegmentSummary)
+                        .filter_by(chunk_id=segment.id, dataset_id=dataset.id, status="completed")
+                        .first()
+                    )
+                    if existing_summary:
+                        continue
+
+                    # For parent-child mode, all segments are parent chunks, so process all
+                    segments_to_process.append(segment)
+
+                if not segments_to_process:
+                    logger.info(f"No segments need summary generation for document {document.id}")
+                    return
+
+                # Use ThreadPoolExecutor for concurrent generation
+                flask_app = current_app._get_current_object()  # type: ignore
+                max_workers = min(10, len(segments_to_process))  # Limit to 10 workers
+
+                def process_segment(segment: DocumentSegment) -> None:
+                    """Process a single segment in a thread with Flask app context."""
+                    with flask_app.app_context():
+                        try:
+                            SummaryIndexService.generate_and_vectorize_summary(
+                                segment, dataset, summary_index_setting
+                            )
+                        except Exception as e:
+                            logger.error(f"Failed to generate summary for segment {segment.id}: {str(e)}")
+                            # Continue processing other segments
+
+                with concurrent.futures.ThreadPoolExecutor(max_workers=max_workers) as executor:
+                    futures = [
+                        executor.submit(process_segment, segment) for segment in segments_to_process
+                    ]
+                    # Wait for all tasks to complete
+                    concurrent.futures.wait(futures)
+
+                logger.info(
+                    f"Successfully generated summary index for {len(segments_to_process)} segments "
+                    f"in document {document.id}"
+                )
+            except Exception as e:
+                logger.exception(f"Failed to generate summary index for document {document.id}: {str(e)}")
+                # Don't fail the entire indexing process if summary generation fails
+        else:
+            # Production mode: asynchronous generation
+            logger.info(f"Queuing summary index generation task for document {document.id} (production mode)")
+            try:
+                generate_summary_index_task.delay(dataset.id, document.id, None)
+                logger.info(f"Summary index generation task queued for document {document.id}")
+            except Exception as e:
+                logger.exception(f"Failed to queue summary index generation task for document {document.id}: {str(e)}")
+                # Don't fail the entire indexing process if task queuing fails
+
+    def _get_preview_output_with_summaries(
+        self, chunk_structure: str, chunks: Any, dataset: Dataset,
+        indexing_technique: str | None = None,
+        summary_index_setting: dict | None = None
+    ) -> Mapping[str, Any]:
+        """
+        Generate preview output with summaries for chunks in preview mode.
+        This method generates summaries on-the-fly without saving to database.
+        
+        Args:
+            chunk_structure: Chunk structure type
+            chunks: Chunks to generate preview for
+            dataset: Dataset object (for tenant_id)
+            indexing_technique: Indexing technique from node config or dataset
+            summary_index_setting: Summary index setting from node config or dataset
+        """
         index_processor = IndexProcessorFactory(chunk_structure).init_index_processor()
-        return index_processor.format_preview(chunks)
+        preview_output = index_processor.format_preview(chunks)
+        
+        # Check if summary index is enabled
+        if indexing_technique != "high_quality":
+            return preview_output
+        
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            return preview_output
+        
+        # Generate summaries for chunks
+        if "preview" in preview_output and isinstance(preview_output["preview"], list):
+            chunk_count = len(preview_output["preview"])
+            logger.info(
+                f"Generating summaries for {chunk_count} chunks in preview mode "
+                f"(dataset: {dataset.id})"
+            )
+            # Use ParagraphIndexProcessor's generate_summary method
+            from core.rag.index_processor.processor.paragraph_index_processor import ParagraphIndexProcessor
+            
+            # Get Flask app for application context in worker threads
+            flask_app = None
+            try:
+                flask_app = current_app._get_current_object()  # type: ignore
+            except RuntimeError:
+                logger.warning("No Flask application context available, summary generation may fail")
+            
+            def generate_summary_for_chunk(preview_item: dict) -> None:
+                """Generate summary for a single chunk."""
+                if "content" in preview_item:
+                    try:
+                        # Set Flask application context in worker thread
+                        if flask_app:
+                            with flask_app.app_context():
+                                summary = ParagraphIndexProcessor.generate_summary(
+                                    tenant_id=dataset.tenant_id,
+                                    text=preview_item["content"],
+                                    summary_index_setting=summary_index_setting,
+                                )
+                                if summary:
+                                    preview_item["summary"] = summary
+                        else:
+                            # Fallback: try without app context (may fail)
+                            summary = ParagraphIndexProcessor.generate_summary(
+                                tenant_id=dataset.tenant_id,
+                                text=preview_item["content"],
+                                summary_index_setting=summary_index_setting,
+                            )
+                            if summary:
+                                preview_item["summary"] = summary
+                    except Exception as e:
+                        logger.error(f"Failed to generate summary for chunk: {str(e)}")
+                        # Don't fail the entire preview if summary generation fails
+            
+            # Generate summaries concurrently using ThreadPoolExecutor
+            # Set a reasonable timeout to prevent hanging (60 seconds per chunk, max 5 minutes total)
+            timeout_seconds = min(300, 60 * len(preview_output["preview"]))
+            with concurrent.futures.ThreadPoolExecutor(max_workers=min(10, len(preview_output["preview"]))) as executor:
+                futures = [
+                    executor.submit(generate_summary_for_chunk, preview_item)
+                    for preview_item in preview_output["preview"]
+                ]
+                # Wait for all tasks to complete with timeout
+                done, not_done = concurrent.futures.wait(futures, timeout=timeout_seconds)
+                
+                # Cancel tasks that didn't complete in time
+                if not_done:
+                    logger.warning(
+                        f"Summary generation timeout: {len(not_done)} chunks did not complete within {timeout_seconds}s. "
+                        "Cancelling remaining tasks..."
+                    )
+                    for future in not_done:
+                        future.cancel()
+                    # Wait a bit for cancellation to take effect
+                    concurrent.futures.wait(not_done, timeout=5)
+            
+            completed_count = sum(1 for item in preview_output["preview"] if item.get("summary") is not None)
+            logger.info(
+                f"Completed summary generation for preview chunks: {completed_count}/{len(preview_output['preview'])} succeeded"
+            )
+        
+        return preview_output
+
+    def _get_preview_output(
+        self, chunk_structure: str, chunks: Any, dataset: Dataset | None = None, variable_pool: VariablePool | None = None
+    ) -> Mapping[str, Any]:
+        index_processor = IndexProcessorFactory(chunk_structure).init_index_processor()
+        preview_output = index_processor.format_preview(chunks)
+        
+        # If dataset is provided, try to enrich preview with summaries
+        if dataset and variable_pool:
+            document_id = variable_pool.get(["sys", SystemVariableKey.DOCUMENT_ID])
+            if document_id:
+                document = db.session.query(Document).filter_by(id=document_id.value).first()
+                if document:
+                    # Query summaries for this document
+                    summaries = (
+                        db.session.query(DocumentSegmentSummary)
+                        .filter_by(
+                            dataset_id=dataset.id,
+                            document_id=document.id,
+                            status="completed",
+                            enabled=True,
+                        )
+                        .all()
+                    )
+                    
+                    if summaries:
+                        # Create a map of segment content to summary for matching
+                        # Use content matching as chunks in preview might not be indexed yet
+                        summary_by_content = {}
+                        for summary in summaries:
+                            segment = (
+                                db.session.query(DocumentSegment)
+                                .filter_by(id=summary.chunk_id, dataset_id=dataset.id)
+                                .first()
+                            )
+                            if segment:
+                                # Normalize content for matching (strip whitespace)
+                                normalized_content = segment.content.strip()
+                                summary_by_content[normalized_content] = summary.summary_content
+                        
+                        # Enrich preview with summaries by content matching
+                        if "preview" in preview_output and isinstance(preview_output["preview"], list):
+                            matched_count = 0
+                            for preview_item in preview_output["preview"]:
+                                if "content" in preview_item:
+                                    # Normalize content for matching
+                                    normalized_chunk_content = preview_item["content"].strip()
+                                    if normalized_chunk_content in summary_by_content:
+                                        preview_item["summary"] = summary_by_content[normalized_chunk_content]
+                                        matched_count += 1
+                            
+                            if matched_count > 0:
+                                logger.info(
+                                    f"Enriched preview with {matched_count} existing summaries "
+                                    f"(dataset: {dataset.id}, document: {document.id})"
+                                )
+        
+        return preview_output
 
     @classmethod
     def version(cls) -> str:

api/extensions/ext_celery.py

@@ -99,6 +99,8 @@ def init_app(app: DifyApp) -> Celery:
     imports = [
         "tasks.async_workflow_tasks",  # trigger workers
         "tasks.trigger_processing_tasks",  # async trigger processing
+        "tasks.generate_summary_index_task",  # summary index generation
+        "tasks.regenerate_summary_index_task",  # summary index regeneration
     ]
     day = dify_config.CELERY_BEAT_SCHEDULER_TIME
 

api/fields/dataset_fields.py

@@ -39,6 +39,14 @@ dataset_retrieval_model_fields = {
     "score_threshold_enabled": fields.Boolean,
     "score_threshold": fields.Float,
 }
+
+dataset_summary_index_fields = {
+    "enable": fields.Boolean,
+    "model_name": fields.String,
+    "model_provider_name": fields.String,
+    "summary_prompt": fields.String,
+}
+
 external_retrieval_model_fields = {
     "top_k": fields.Integer,
     "score_threshold": fields.Float,
@@ -83,6 +91,7 @@ dataset_detail_fields = {
     "embedding_model_provider": fields.String,
     "embedding_available": fields.Boolean,
     "retrieval_model_dict": fields.Nested(dataset_retrieval_model_fields),
+    "summary_index_setting": fields.Nested(dataset_summary_index_fields),
     "tags": fields.List(fields.Nested(tag_fields)),
     "doc_form": fields.String,
     "external_knowledge_info": fields.Nested(external_knowledge_info_fields),

api/fields/document_fields.py

@@ -33,6 +33,8 @@ document_fields = {
     "hit_count": fields.Integer,
     "doc_form": fields.String,
     "doc_metadata": fields.List(fields.Nested(document_metadata_fields), attribute="doc_metadata_details"),
+    "summary_index_status": fields.String,  # Summary index generation status: "waiting", "generating", "completed", "partial_error", or null if not enabled
+    "need_summary": fields.Boolean,  # Whether this document needs summary index generation
 }
 
 document_with_segments_fields = {
@@ -60,6 +62,8 @@ document_with_segments_fields = {
     "completed_segments": fields.Integer,
     "total_segments": fields.Integer,
     "doc_metadata": fields.List(fields.Nested(document_metadata_fields), attribute="doc_metadata_details"),
+    "summary_index_status": fields.String,  # Summary index generation status: "waiting", "generating", "completed", "partial_error", or null if not enabled
+    "need_summary": fields.Boolean,  # Whether this document needs summary index generation
 }
 
 dataset_and_document_fields = {

api/fields/hit_testing_fields.py

@@ -58,4 +58,5 @@ hit_testing_record_fields = {
     "score": fields.Float,
     "tsne_position": fields.Raw,
     "files": fields.List(fields.Nested(files_fields)),
+    "summary": fields.String,  # Summary content if retrieved via summary index
 }

api/fields/segment_fields.py

@@ -49,4 +49,5 @@ segment_fields = {
     "stopped_at": TimestampField,
     "child_chunks": fields.List(fields.Nested(child_chunk_fields)),
     "attachments": fields.List(fields.Nested(attachment_fields)),
+    "summary": fields.String,  # Summary content for the segment
 }

api/migrations/versions/2026_01_12_1358-562dcce7d77c_add_summaryindex_feature.py

@@ -0,0 +1,69 @@
+"""add SummaryIndex feature
+
+Revision ID: 562dcce7d77c
+Revises: 03ea244985ce
+Create Date: 2026-01-12 13:58:40.584802
+
+"""
+from alembic import op
+import models as models
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '562dcce7d77c'
+down_revision = '03ea244985ce'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('document_segment_summary',
+    sa.Column('id', models.types.StringUUID(), nullable=False),
+    sa.Column('dataset_id', models.types.StringUUID(), nullable=False),
+    sa.Column('document_id', models.types.StringUUID(), nullable=False),
+    sa.Column('chunk_id', models.types.StringUUID(), nullable=False),
+    sa.Column('summary_content', models.types.LongText(), nullable=True),
+    sa.Column('summary_index_node_id', sa.String(length=255), nullable=True),
+    sa.Column('summary_index_node_hash', sa.String(length=255), nullable=True),
+    sa.Column('status', sa.String(length=32), server_default=sa.text("'generating'"), nullable=False),
+    sa.Column('error', models.types.LongText(), nullable=True),
+    sa.Column('enabled', sa.Boolean(), server_default=sa.text('true'), nullable=False),
+    sa.Column('disabled_at', sa.DateTime(), nullable=True),
+    sa.Column('disabled_by', models.types.StringUUID(), nullable=True),
+    sa.Column('created_at', sa.DateTime(), server_default=sa.text('CURRENT_TIMESTAMP'), nullable=False),
+    sa.Column('updated_at', sa.DateTime(), server_default=sa.text('CURRENT_TIMESTAMP'), nullable=False),
+    sa.PrimaryKeyConstraint('id', name='document_segment_summary_pkey')
+    )
+    with op.batch_alter_table('document_segment_summary', schema=None) as batch_op:
+        batch_op.create_index('document_segment_summary_chunk_id_idx', ['chunk_id'], unique=False)
+        batch_op.create_index('document_segment_summary_dataset_id_idx', ['dataset_id'], unique=False)
+        batch_op.create_index('document_segment_summary_document_id_idx', ['document_id'], unique=False)
+        batch_op.create_index('document_segment_summary_status_idx', ['status'], unique=False)
+
+    with op.batch_alter_table('datasets', schema=None) as batch_op:
+        batch_op.add_column(sa.Column('summary_index_setting', models.types.AdjustedJSON(), nullable=True))
+
+    with op.batch_alter_table('documents', schema=None) as batch_op:
+        batch_op.add_column(sa.Column('need_summary', sa.Boolean(), server_default=sa.text('false'), nullable=True))
+
+    # ### end Alembic commands ###
+
+
+def downgrade():
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table('documents', schema=None) as batch_op:
+        batch_op.drop_column('need_summary')
+
+    with op.batch_alter_table('datasets', schema=None) as batch_op:
+        batch_op.drop_column('summary_index_setting')
+
+    with op.batch_alter_table('document_segment_summary', schema=None) as batch_op:
+        batch_op.drop_index('document_segment_summary_status_idx')
+        batch_op.drop_index('document_segment_summary_document_id_idx')
+        batch_op.drop_index('document_segment_summary_dataset_id_idx')
+        batch_op.drop_index('document_segment_summary_chunk_id_idx')
+
+    op.drop_table('document_segment_summary')
+    # ### end Alembic commands ###

api/models/dataset.py

@@ -72,6 +72,7 @@ class Dataset(Base):
     keyword_number = mapped_column(sa.Integer, nullable=True, server_default=sa.text("10"))
     collection_binding_id = mapped_column(StringUUID, nullable=True)
     retrieval_model = mapped_column(AdjustedJSON, nullable=True)
+    summary_index_setting = mapped_column(AdjustedJSON, nullable=True)
     built_in_field_enabled = mapped_column(sa.Boolean, nullable=False, server_default=sa.text("false"))
     icon_info = mapped_column(AdjustedJSON, nullable=True)
     runtime_mode = mapped_column(sa.String(255), nullable=True, server_default=sa.text("'general'"))
@@ -419,6 +420,7 @@ class Document(Base):
     doc_metadata = mapped_column(AdjustedJSON, nullable=True)
     doc_form = mapped_column(String(255), nullable=False, server_default=sa.text("'text_model'"))
     doc_language = mapped_column(String(255), nullable=True)
+    need_summary: Mapped[bool | None] = mapped_column(sa.Boolean, nullable=True, server_default=sa.text("false"))
 
     DATA_SOURCES = ["upload_file", "notion_import", "website_crawl"]
 
@@ -1567,3 +1569,34 @@ class SegmentAttachmentBinding(Base):
     segment_id: Mapped[str] = mapped_column(StringUUID, nullable=False)
     attachment_id: Mapped[str] = mapped_column(StringUUID, nullable=False)
     created_at: Mapped[datetime] = mapped_column(sa.DateTime, nullable=False, server_default=func.current_timestamp())
+
+
+class DocumentSegmentSummary(Base):
+    __tablename__ = "document_segment_summary"
+    __table_args__ = (
+        sa.PrimaryKeyConstraint("id", name="document_segment_summary_pkey"),
+        sa.Index("document_segment_summary_dataset_id_idx", "dataset_id"),
+        sa.Index("document_segment_summary_document_id_idx", "document_id"),
+        sa.Index("document_segment_summary_chunk_id_idx", "chunk_id"),
+        sa.Index("document_segment_summary_status_idx", "status"),
+    )
+
+    id: Mapped[str] = mapped_column(StringUUID, nullable=False, default=lambda: str(uuid4()))
+    dataset_id: Mapped[str] = mapped_column(StringUUID, nullable=False)
+    document_id: Mapped[str] = mapped_column(StringUUID, nullable=False)
+    # corresponds to DocumentSegment.id or parent chunk id
+    chunk_id: Mapped[str] = mapped_column(StringUUID, nullable=False)
+    summary_content: Mapped[str] = mapped_column(LongText, nullable=True)
+    summary_index_node_id: Mapped[str] = mapped_column(String(255), nullable=True)
+    summary_index_node_hash: Mapped[str] = mapped_column(String(255), nullable=True)
+    status: Mapped[str] = mapped_column(String(32), nullable=False, server_default=sa.text("'generating'"))
+    error: Mapped[str] = mapped_column(LongText, nullable=True)
+    enabled: Mapped[bool] = mapped_column(sa.Boolean, nullable=False, server_default=sa.text("true"))
+    disabled_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
+    disabled_by = mapped_column(StringUUID, nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, server_default=func.current_timestamp())
+    updated_at: Mapped[datetime] = mapped_column(DateTime, nullable=False, server_default=func.current_timestamp(), onupdate=func.current_timestamp())
+
+    def __repr__(self):
+        return f"<DocumentSegmentSummary id={self.id} chunk_id={self.chunk_id} status={self.status}>"
+

api/services/dataset_service.py

@@ -89,6 +89,7 @@ from tasks.enable_segments_to_index_task import enable_segments_to_index_task
 from tasks.recover_document_indexing_task import recover_document_indexing_task
 from tasks.remove_document_from_index_task import remove_document_from_index_task
 from tasks.retry_document_indexing_task import retry_document_indexing_task
+from tasks.regenerate_summary_index_task import regenerate_summary_index_task
 from tasks.sync_website_document_indexing_task import sync_website_document_indexing_task
 
 logger = logging.getLogger(__name__)
@@ -473,6 +474,11 @@ class DatasetService:
         if external_retrieval_model:
             dataset.retrieval_model = external_retrieval_model
 
+        # Update summary index setting if provided
+        summary_index_setting = data.get("summary_index_setting", None)
+        if summary_index_setting is not None:
+            dataset.summary_index_setting = summary_index_setting
+
         # Update basic dataset properties
         dataset.name = data.get("name", dataset.name)
         dataset.description = data.get("description", dataset.description)
@@ -555,12 +561,20 @@ class DatasetService:
         # Handle indexing technique changes and embedding model updates
         action = DatasetService._handle_indexing_technique_change(dataset, data, filtered_data)
 
+        # Check if summary_index_setting model changed (before updating database)
+        summary_model_changed = DatasetService._check_summary_index_setting_model_changed(
+            dataset, data
+        )
+
         # Add metadata fields
         filtered_data["updated_by"] = user.id
         filtered_data["updated_at"] = naive_utc_now()
         # update Retrieval model
         if data.get("retrieval_model"):
             filtered_data["retrieval_model"] = data["retrieval_model"]
+        # update summary index setting
+        if data.get("summary_index_setting"):
+            filtered_data["summary_index_setting"] = data.get("summary_index_setting")
         # update icon info
         if data.get("icon_info"):
             filtered_data["icon_info"] = data.get("icon_info")
@@ -569,12 +583,30 @@ class DatasetService:
         db.session.query(Dataset).filter_by(id=dataset.id).update(filtered_data)
         db.session.commit()
 
+        # Reload dataset to get updated values
+        db.session.refresh(dataset)
+
         # update pipeline knowledge base node data
         DatasetService._update_pipeline_knowledge_base_node_data(dataset, user.id)
 
         # Trigger vector index task if indexing technique changed
         if action:
             deal_dataset_vector_index_task.delay(dataset.id, action)
+            # If embedding_model changed, also regenerate summary vectors
+            if action == "update":
+                regenerate_summary_index_task.delay(
+                    dataset.id,
+                    regenerate_reason="embedding_model_changed",
+                    regenerate_vectors_only=True,
+                )
+
+        # Trigger summary index regeneration if summary model changed
+        if summary_model_changed:
+            regenerate_summary_index_task.delay(
+                dataset.id,
+                regenerate_reason="summary_model_changed",
+                regenerate_vectors_only=False,
+            )
 
         return dataset
 
@@ -613,6 +645,7 @@ class DatasetService:
                             knowledge_index_node_data["chunk_structure"] = dataset.chunk_structure
                             knowledge_index_node_data["indexing_technique"] = dataset.indexing_technique  # pyright: ignore[reportAttributeAccessIssue]
                             knowledge_index_node_data["keyword_number"] = dataset.keyword_number
+                            knowledge_index_node_data["summary_index_setting"] = dataset.summary_index_setting
                             node["data"] = knowledge_index_node_data
                             updated = True
                         except Exception:
@@ -851,6 +884,49 @@ class DatasetService:
         )
         filtered_data["collection_binding_id"] = dataset_collection_binding.id
 
+    @staticmethod
+    def _check_summary_index_setting_model_changed(dataset: Dataset, data: dict[str, Any]) -> bool:
+        """
+        Check if summary_index_setting model (model_name or model_provider_name) has changed.
+
+        Args:
+            dataset: Current dataset object
+            data: Update data dictionary
+
+        Returns:
+            bool: True if summary model changed, False otherwise
+        """
+        # Check if summary_index_setting is being updated
+        if "summary_index_setting" not in data or data.get("summary_index_setting") is None:
+            return False
+
+        new_summary_setting = data.get("summary_index_setting")
+        old_summary_setting = dataset.summary_index_setting
+
+        # If old setting doesn't exist or is disabled, no need to regenerate
+        if not old_summary_setting or not old_summary_setting.get("enable"):
+            return False
+
+        # If new setting is disabled, no need to regenerate
+        if not new_summary_setting or not new_summary_setting.get("enable"):
+            return False
+
+        # Compare model_name and model_provider_name
+        old_model_name = old_summary_setting.get("model_name")
+        old_model_provider = old_summary_setting.get("model_provider_name")
+        new_model_name = new_summary_setting.get("model_name")
+        new_model_provider = new_summary_setting.get("model_provider_name")
+
+        # Check if model changed
+        if old_model_name != new_model_name or old_model_provider != new_model_provider:
+            logger.info(
+                f"Summary index setting model changed for dataset {dataset.id}: "
+                f"old={old_model_provider}/{old_model_name}, new={new_model_provider}/{new_model_name}"
+            )
+            return True
+
+        return False
+
     @staticmethod
     def update_rag_pipeline_dataset_settings(
         session: Session, dataset: Dataset, knowledge_configuration: KnowledgeConfiguration, has_published: bool = False
@@ -1823,6 +1899,8 @@ class DocumentService:
                         DuplicateDocumentIndexingTaskProxy(
                             dataset.tenant_id, dataset.id, duplicate_document_ids
                         ).delay()
+                    # Note: Summary index generation is triggered in document_indexing_task after indexing completes
+                    # to ensure segments are available. See tasks/document_indexing_task.py
             except LockNotOwnedError:
                 pass
 
@@ -2127,6 +2205,14 @@ class DocumentService:
         name: str,
         batch: str,
     ):
+        # Set need_summary based on dataset's summary_index_setting
+        need_summary = False
+        if (
+            dataset.summary_index_setting
+            and dataset.summary_index_setting.get("enable") is True
+        ):
+            need_summary = True
+        
         document = Document(
             tenant_id=dataset.tenant_id,
             dataset_id=dataset.id,
@@ -2140,6 +2226,7 @@ class DocumentService:
             created_by=account.id,
             doc_form=document_form,
             doc_language=document_language,
+            need_summary=need_summary,
         )
         doc_metadata = {}
         if dataset.built_in_field_enabled:
@@ -2364,6 +2451,7 @@ class DocumentService:
             embedding_model_provider=knowledge_config.embedding_model_provider,
             collection_binding_id=dataset_collection_binding_id,
             retrieval_model=retrieval_model.model_dump() if retrieval_model else None,
+            summary_index_setting=knowledge_config.summary_index_setting,
             is_multimodal=knowledge_config.is_multimodal,
         )
 
@@ -2545,6 +2633,14 @@ class DocumentService:
             if not isinstance(args["process_rule"]["rules"]["segmentation"]["max_tokens"], int):
                 raise ValueError("Process rule segmentation max_tokens is invalid")
 
+        # valid summary index setting
+        if args["process_rule"]["summary_index_setting"] and args["process_rule"]["summary_index_setting"]["enable"]:
+            summary_index_setting = args["process_rule"]["summary_index_setting"]
+            if "model_name" not in summary_index_setting or not summary_index_setting["model_name"]:
+                raise ValueError("Summary index model name is required")
+            if "model_provider_name" not in summary_index_setting or not summary_index_setting["model_provider_name"]:
+                raise ValueError("Summary index model provider name is required")
+
     @staticmethod
     def batch_update_document_status(
         dataset: Dataset, document_ids: list[str], action: Literal["enable", "disable", "archive", "un_archive"], user
@@ -3013,6 +3109,37 @@ class SegmentService:
                     if args.enabled or keyword_changed:
                         # update segment vector index
                         VectorService.update_segment_vector(args.keywords, segment, dataset)
+                # update summary index if summary is provided and has changed
+                if args.summary is not None:
+                    # Check if summary index is enabled
+                    has_summary_index = (
+                        dataset.indexing_technique == "high_quality"
+                        and dataset.summary_index_setting
+                        and dataset.summary_index_setting.get("enable") is True
+                    )
+                    
+                    if has_summary_index:
+                        # Query existing summary from database
+                        from models.dataset import DocumentSegmentSummary
+                        existing_summary = (
+                            db.session.query(DocumentSegmentSummary)
+                            .where(
+                                DocumentSegmentSummary.chunk_id == segment.id,
+                                DocumentSegmentSummary.dataset_id == dataset.id,
+                            )
+                            .first()
+                        )
+                        
+                        # Check if summary has changed
+                        existing_summary_content = existing_summary.summary_content if existing_summary else None
+                        if existing_summary_content != args.summary:
+                            # Summary has changed, update it
+                            from services.summary_index_service import SummaryIndexService
+                            try:
+                                SummaryIndexService.update_summary_for_segment(segment, dataset, args.summary)
+                            except Exception as e:
+                                logger.exception(f"Failed to update summary for segment {segment.id}: {str(e)}")
+                                # Don't fail the entire update if summary update fails
             else:
                 segment_hash = helper.generate_text_hash(content)
                 tokens = 0
@@ -3087,6 +3214,15 @@ class SegmentService:
                 elif document.doc_form in (IndexStructureType.PARAGRAPH_INDEX, IndexStructureType.QA_INDEX):
                     # update segment vector index
                     VectorService.update_segment_vector(args.keywords, segment, dataset)
+            # update summary index if summary is provided
+            if args.summary is not None:
+                from services.summary_index_service import SummaryIndexService
+
+                try:
+                    SummaryIndexService.update_summary_for_segment(segment, dataset, args.summary)
+                except Exception as e:
+                    logger.exception(f"Failed to update summary for segment {segment.id}: {str(e)}")
+                    # Don't fail the entire update if summary update fails
             # update multimodel vector index
             VectorService.update_multimodel_vector(segment, args.attachment_ids or [], dataset)
         except Exception as e:

api/services/entities/knowledge_entities/knowledge_entities.py

@@ -119,6 +119,7 @@ class KnowledgeConfig(BaseModel):
     data_source: DataSource | None = None
     process_rule: ProcessRule | None = None
     retrieval_model: RetrievalModel | None = None
+    summary_index_setting: dict | None = None
     doc_form: str = "text_model"
     doc_language: str = "English"
     embedding_model: str | None = None
@@ -141,6 +142,7 @@ class SegmentUpdateArgs(BaseModel):
     regenerate_child_chunks: bool = False
     enabled: bool | None = None
     attachment_ids: list[str] | None = None
+    summary: str | None = None  # Summary content for summary index
 
 
 class ChildChunkUpdateArgs(BaseModel):

api/services/summary_index_service.py

@@ -0,0 +1,612 @@
+"""Summary index service for generating and managing document segment summaries."""
+
+import logging
+import time
+import uuid
+from typing import Any
+
+from core.rag.datasource.vdb.vector_factory import Vector
+from core.rag.index_processor.constant.doc_type import DocType
+from core.rag.models.document import Document
+from extensions.ext_database import db
+from libs import helper
+from models.dataset import Dataset, DocumentSegment, DocumentSegmentSummary
+from models.dataset import Document as DatasetDocument
+
+logger = logging.getLogger(__name__)
+
+
+class SummaryIndexService:
+    """Service for generating and managing summary indexes."""
+
+    @staticmethod
+    def generate_summary_for_segment(
+        segment: DocumentSegment,
+        dataset: Dataset,
+        summary_index_setting: dict,
+    ) -> str:
+        """
+        Generate summary for a single segment.
+
+        Args:
+            segment: DocumentSegment to generate summary for
+            dataset: Dataset containing the segment
+            summary_index_setting: Summary index configuration
+
+        Returns:
+            Generated summary text
+
+        Raises:
+            ValueError: If summary_index_setting is invalid or generation fails
+        """
+        # Reuse the existing generate_summary method from ParagraphIndexProcessor
+        # Use lazy import to avoid circular import
+        from core.rag.index_processor.processor.paragraph_index_processor import ParagraphIndexProcessor
+
+        summary_content = ParagraphIndexProcessor.generate_summary(
+            tenant_id=dataset.tenant_id,
+            text=segment.content,
+            summary_index_setting=summary_index_setting,
+        )
+
+        if not summary_content:
+            raise ValueError("Generated summary is empty")
+
+        return summary_content
+
+    @staticmethod
+    def create_summary_record(
+        segment: DocumentSegment,
+        dataset: Dataset,
+        summary_content: str,
+        status: str = "generating",
+    ) -> DocumentSegmentSummary:
+        """
+        Create or update a DocumentSegmentSummary record.
+        If a summary record already exists for this segment, it will be updated instead of creating a new one.
+
+        Args:
+            segment: DocumentSegment to create summary for
+            dataset: Dataset containing the segment
+            summary_content: Generated summary content
+            status: Summary status (default: "generating")
+
+        Returns:
+            Created or updated DocumentSegmentSummary instance
+        """
+        # Check if summary record already exists
+        existing_summary = (
+            db.session.query(DocumentSegmentSummary)
+            .filter_by(chunk_id=segment.id, dataset_id=dataset.id)
+            .first()
+        )
+        
+        if existing_summary:
+            # Update existing record
+            existing_summary.summary_content = summary_content
+            existing_summary.status = status
+            existing_summary.error = None  # Clear any previous errors
+            # Re-enable if it was disabled
+            if not existing_summary.enabled:
+                existing_summary.enabled = True
+                existing_summary.disabled_at = None
+                existing_summary.disabled_by = None
+            db.session.add(existing_summary)
+            db.session.flush()
+            return existing_summary
+        else:
+            # Create new record (enabled by default)
+            summary_record = DocumentSegmentSummary(
+                dataset_id=dataset.id,
+                document_id=segment.document_id,
+                chunk_id=segment.id,
+                summary_content=summary_content,
+                status=status,
+                enabled=True,  # Explicitly set enabled to True
+            )
+            db.session.add(summary_record)
+            db.session.flush()
+            return summary_record
+
+    @staticmethod
+    def vectorize_summary(
+        summary_record: DocumentSegmentSummary,
+        segment: DocumentSegment,
+        dataset: Dataset,
+    ) -> None:
+        """
+        Vectorize summary and store in vector database.
+
+        Args:
+            summary_record: DocumentSegmentSummary record
+            segment: Original DocumentSegment
+            dataset: Dataset containing the segment
+        """
+        if dataset.indexing_technique != "high_quality":
+            logger.warning(
+                f"Summary vectorization skipped for dataset {dataset.id}: "
+                "indexing_technique is not high_quality"
+            )
+            return
+
+        # Reuse existing index_node_id if available (like segment does), otherwise generate new one
+        old_summary_node_id = summary_record.summary_index_node_id
+        if old_summary_node_id:
+            # Reuse existing index_node_id (like segment behavior)
+            summary_index_node_id = old_summary_node_id
+        else:
+            # Generate new index node ID only for new summaries
+            summary_index_node_id = str(uuid.uuid4())
+        
+        # Always regenerate hash (in case summary content changed)
+        summary_hash = helper.generate_text_hash(summary_record.summary_content)
+        
+        # Delete old vector only if we're reusing the same index_node_id (to overwrite)
+        # If index_node_id changed, the old vector should have been deleted elsewhere
+        if old_summary_node_id and old_summary_node_id == summary_index_node_id:
+            try:
+                vector = Vector(dataset)
+                vector.delete_by_ids([old_summary_node_id])
+            except Exception as e:
+                logger.warning(
+                    f"Failed to delete old summary vector for segment {segment.id}: {str(e)}. "
+                    "Continuing with new vectorization."
+                )
+
+        # Create document with summary content and metadata
+        summary_document = Document(
+            page_content=summary_record.summary_content,
+            metadata={
+                "doc_id": summary_index_node_id,
+                "doc_hash": summary_hash,
+                "dataset_id": dataset.id,
+                "document_id": segment.document_id,
+                "original_chunk_id": segment.id,  # Key: link to original chunk
+                "doc_type": DocType.TEXT,
+                "is_summary": True,  # Identifier for summary documents
+            },
+        )
+
+        # Vectorize and store with retry mechanism for connection errors
+        max_retries = 3
+        retry_delay = 2.0
+        
+        for attempt in range(max_retries):
+            try:
+                vector = Vector(dataset)
+                vector.add_texts([summary_document], duplicate_check=True)
+                
+                # Success - update summary record with index node info
+                summary_record.summary_index_node_id = summary_index_node_id
+                summary_record.summary_index_node_hash = summary_hash
+                summary_record.status = "completed"
+                db.session.add(summary_record)
+                db.session.flush()
+                return  # Success, exit function
+                
+            except (ConnectionError, Exception) as e:
+                error_str = str(e).lower()
+                # Check if it's a connection-related error that might be transient
+                is_connection_error = any(keyword in error_str for keyword in [
+                    "connection", "disconnected", "timeout", "network", 
+                    "could not connect", "server disconnected", "weaviate"
+                ])
+                
+                if is_connection_error and attempt < max_retries - 1:
+                    # Retry for connection errors
+                    wait_time = retry_delay * (2 ** attempt)  # Exponential backoff
+                    logger.warning(
+                        f"Vectorization attempt {attempt + 1}/{max_retries} failed for segment {segment.id}: {str(e)}. "
+                        f"Retrying in {wait_time:.1f} seconds..."
+                    )
+                    time.sleep(wait_time)
+                    continue
+                else:
+                    # Final attempt failed or non-connection error - log and update status
+                    logger.error(
+                        f"Failed to vectorize summary for segment {segment.id} after {attempt + 1} attempts: {str(e)}",
+                        exc_info=True
+                    )
+                    summary_record.status = "error"
+                    summary_record.error = f"Vectorization failed: {str(e)}"
+                    db.session.add(summary_record)
+                    db.session.flush()
+                    raise
+
+    @staticmethod
+    def generate_and_vectorize_summary(
+        segment: DocumentSegment,
+        dataset: Dataset,
+        summary_index_setting: dict,
+    ) -> DocumentSegmentSummary:
+        """
+        Generate summary for a segment and vectorize it.
+
+        Args:
+            segment: DocumentSegment to generate summary for
+            dataset: Dataset containing the segment
+            summary_index_setting: Summary index configuration
+
+        Returns:
+            Created DocumentSegmentSummary instance
+
+        Raises:
+            ValueError: If summary generation fails
+        """
+        try:
+            # Generate summary
+            summary_content = SummaryIndexService.generate_summary_for_segment(
+                segment, dataset, summary_index_setting
+            )
+
+            # Create or update summary record (will handle overwrite internally)
+            summary_record = SummaryIndexService.create_summary_record(
+                segment, dataset, summary_content, status="generating"
+            )
+
+            # Vectorize summary (will delete old vector if exists before creating new one)
+            SummaryIndexService.vectorize_summary(summary_record, segment, dataset)
+
+            db.session.commit()
+            logger.info(f"Successfully generated and vectorized summary for segment {segment.id}")
+            return summary_record
+
+        except Exception as e:
+            logger.exception(f"Failed to generate summary for segment {segment.id}: {str(e)}")
+            # Update summary record with error status if it exists
+            summary_record = (
+                db.session.query(DocumentSegmentSummary)
+                .filter_by(chunk_id=segment.id, dataset_id=dataset.id)
+                .first()
+            )
+            if summary_record:
+                summary_record.status = "error"
+                summary_record.error = str(e)
+                db.session.add(summary_record)
+                db.session.commit()
+            raise
+
+    @staticmethod
+    def generate_summaries_for_document(
+        dataset: Dataset,
+        document: DatasetDocument,
+        summary_index_setting: dict,
+        segment_ids: list[str] | None = None,
+        only_parent_chunks: bool = False,
+    ) -> list[DocumentSegmentSummary]:
+        """
+        Generate summaries for all segments in a document including vectorization.
+
+        Args:
+            dataset: Dataset containing the document
+            document: DatasetDocument to generate summaries for
+            summary_index_setting: Summary index configuration
+            segment_ids: Optional list of specific segment IDs to process
+            only_parent_chunks: If True, only process parent chunks (for parent-child mode)
+
+        Returns:
+            List of created DocumentSegmentSummary instances
+        """
+        # Only generate summary index for high_quality indexing technique
+        if dataset.indexing_technique != "high_quality":
+            logger.info(
+                f"Skipping summary generation for dataset {dataset.id}: "
+                f"indexing_technique is {dataset.indexing_technique}, not 'high_quality'"
+            )
+            return []
+
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            logger.info(f"Summary index is disabled for dataset {dataset.id}")
+            return []
+
+        # Skip qa_model documents
+        if document.doc_form == "qa_model":
+            logger.info(f"Skipping summary generation for qa_model document {document.id}")
+            return []
+
+        logger.info(
+            f"Starting summary generation for document {document.id} in dataset {dataset.id}, "
+            f"segment_ids: {len(segment_ids) if segment_ids else 'all'}, "
+            f"only_parent_chunks: {only_parent_chunks}"
+        )
+
+        # Query segments (only enabled segments)
+        query = db.session.query(DocumentSegment).filter_by(
+            dataset_id=dataset.id,
+            document_id=document.id,
+            status="completed",
+            enabled=True,  # Only generate summaries for enabled segments
+        )
+
+        if segment_ids:
+            query = query.filter(DocumentSegment.id.in_(segment_ids))
+
+        segments = query.all()
+
+        if not segments:
+            logger.info(f"No segments found for document {document.id}")
+            return []
+
+        summary_records = []
+
+        for segment in segments:
+            # For parent-child mode, only process parent chunks
+            # In parent-child mode, all DocumentSegments are parent chunks,
+            # so we process all of them. Child chunks are stored in ChildChunk table
+            # and are not DocumentSegments, so they won't be in the segments list.
+            # This check is mainly for clarity and future-proofing.
+            if only_parent_chunks:
+                # In parent-child mode, all segments in the query are parent chunks
+                # Child chunks are not DocumentSegments, so they won't appear here
+                # We can process all segments
+                pass
+
+            try:
+                summary_record = SummaryIndexService.generate_and_vectorize_summary(
+                    segment, dataset, summary_index_setting
+                )
+                summary_records.append(summary_record)
+            except Exception as e:
+                logger.error(f"Failed to generate summary for segment {segment.id}: {str(e)}")
+                # Continue with other segments
+                continue
+
+        logger.info(
+            f"Completed summary generation for document {document.id}: "
+            f"{len(summary_records)} summaries generated and vectorized"
+        )
+        return summary_records
+
+    @staticmethod
+    def disable_summaries_for_segments(
+        dataset: Dataset,
+        segment_ids: list[str] | None = None,
+        disabled_by: str | None = None,
+    ) -> None:
+        """
+        Disable summary records and remove vectors from vector database for segments.
+        Unlike delete, this preserves the summary records but marks them as disabled.
+
+        Args:
+            dataset: Dataset containing the segments
+            segment_ids: List of segment IDs to disable summaries for. If None, disable all.
+            disabled_by: User ID who disabled the summaries
+        """
+        from libs.datetime_utils import naive_utc_now
+        
+        query = db.session.query(DocumentSegmentSummary).filter_by(
+            dataset_id=dataset.id,
+            enabled=True,  # Only disable enabled summaries
+        )
+
+        if segment_ids:
+            query = query.filter(DocumentSegmentSummary.chunk_id.in_(segment_ids))
+
+        summaries = query.all()
+
+        if not summaries:
+            return
+
+        logger.info(
+            f"Disabling {len(summaries)} summary records for dataset {dataset.id}, "
+            f"segment_ids: {len(segment_ids) if segment_ids else 'all'}"
+        )
+
+        # Remove from vector database (but keep records)
+        if dataset.indexing_technique == "high_quality":
+            summary_node_ids = [
+                s.summary_index_node_id for s in summaries if s.summary_index_node_id
+            ]
+            if summary_node_ids:
+                try:
+                    vector = Vector(dataset)
+                    vector.delete_by_ids(summary_node_ids)
+                except Exception as e:
+                    logger.warning(f"Failed to remove summary vectors: {str(e)}")
+
+        # Disable summary records (don't delete)
+        now = naive_utc_now()
+        for summary in summaries:
+            summary.enabled = False
+            summary.disabled_at = now
+            summary.disabled_by = disabled_by
+            db.session.add(summary)
+
+        db.session.commit()
+        logger.info(f"Disabled {len(summaries)} summary records for dataset {dataset.id}")
+
+    @staticmethod
+    def enable_summaries_for_segments(
+        dataset: Dataset,
+        segment_ids: list[str] | None = None,
+    ) -> None:
+        """
+        Enable summary records and re-add vectors to vector database for segments.
+
+        Args:
+            dataset: Dataset containing the segments
+            segment_ids: List of segment IDs to enable summaries for. If None, enable all.
+        """
+        # Only enable summary index for high_quality indexing technique
+        if dataset.indexing_technique != "high_quality":
+            return
+
+        # Check if summary index is enabled
+        summary_index_setting = dataset.summary_index_setting
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            return
+
+        query = db.session.query(DocumentSegmentSummary).filter_by(
+            dataset_id=dataset.id,
+            enabled=False,  # Only enable disabled summaries
+        )
+
+        if segment_ids:
+            query = query.filter(DocumentSegmentSummary.chunk_id.in_(segment_ids))
+
+        summaries = query.all()
+
+        if not summaries:
+            return
+
+        logger.info(
+            f"Enabling {len(summaries)} summary records for dataset {dataset.id}, "
+            f"segment_ids: {len(segment_ids) if segment_ids else 'all'}"
+        )
+
+        # Re-vectorize and re-add to vector database
+        enabled_count = 0
+        for summary in summaries:
+            # Get the original segment
+            segment = db.session.query(DocumentSegment).filter_by(
+                id=summary.chunk_id,
+                dataset_id=dataset.id,
+            ).first()
+            
+            if not segment or not segment.enabled or segment.status != "completed":
+                continue
+
+            if not summary.summary_content:
+                continue
+
+            try:
+                # Re-vectorize summary
+                SummaryIndexService.vectorize_summary(summary, segment, dataset)
+                
+                # Enable summary record
+                summary.enabled = True
+                summary.disabled_at = None
+                summary.disabled_by = None
+                db.session.add(summary)
+                enabled_count += 1
+            except Exception as e:
+                logger.error(f"Failed to re-vectorize summary {summary.id}: {str(e)}")
+                # Keep it disabled if vectorization fails
+                continue
+
+        db.session.commit()
+        logger.info(f"Enabled {enabled_count} summary records for dataset {dataset.id}")
+
+    @staticmethod
+    def delete_summaries_for_segments(
+        dataset: Dataset,
+        segment_ids: list[str] | None = None,
+    ) -> None:
+        """
+        Delete summary records and vectors for segments (used only for actual deletion scenarios).
+        For disable/enable operations, use disable_summaries_for_segments/enable_summaries_for_segments.
+
+        Args:
+            dataset: Dataset containing the segments
+            segment_ids: List of segment IDs to delete summaries for. If None, delete all.
+        """
+        query = db.session.query(DocumentSegmentSummary).filter_by(dataset_id=dataset.id)
+
+        if segment_ids:
+            query = query.filter(DocumentSegmentSummary.chunk_id.in_(segment_ids))
+
+        summaries = query.all()
+
+        if not summaries:
+            return
+
+        # Delete from vector database
+        if dataset.indexing_technique == "high_quality":
+            summary_node_ids = [
+                s.summary_index_node_id for s in summaries if s.summary_index_node_id
+            ]
+            if summary_node_ids:
+                vector = Vector(dataset)
+                vector.delete_by_ids(summary_node_ids)
+
+        # Delete summary records
+        for summary in summaries:
+            db.session.delete(summary)
+
+        db.session.commit()
+        logger.info(f"Deleted {len(summaries)} summary records for dataset {dataset.id}")
+
+    @staticmethod
+    def update_summary_for_segment(
+        segment: DocumentSegment,
+        dataset: Dataset,
+        summary_content: str,
+    ) -> DocumentSegmentSummary | None:
+        """
+        Update summary for a segment and re-vectorize it.
+
+        Args:
+            segment: DocumentSegment to update summary for
+            dataset: Dataset containing the segment
+            summary_content: New summary content
+
+        Returns:
+            Updated DocumentSegmentSummary instance, or None if summary index is not enabled
+        """
+        # Only update summary index for high_quality indexing technique
+        if dataset.indexing_technique != "high_quality":
+            return None
+
+        # Check if summary index is enabled
+        summary_index_setting = dataset.summary_index_setting
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            return None
+
+        # Skip qa_model documents
+        if segment.document and segment.document.doc_form == "qa_model":
+            return None
+
+        try:
+            # Find existing summary record
+            summary_record = (
+                db.session.query(DocumentSegmentSummary)
+                .filter_by(chunk_id=segment.id, dataset_id=dataset.id)
+                .first()
+            )
+
+            if summary_record:
+                # Update existing summary
+                old_summary_node_id = summary_record.summary_index_node_id
+
+                # Update summary content
+                summary_record.summary_content = summary_content
+                summary_record.status = "generating"
+                db.session.add(summary_record)
+                db.session.flush()
+
+                # Delete old vector if exists
+                if old_summary_node_id:
+                    vector = Vector(dataset)
+                    vector.delete_by_ids([old_summary_node_id])
+
+                # Re-vectorize summary
+                SummaryIndexService.vectorize_summary(summary_record, segment, dataset)
+
+                db.session.commit()
+                logger.info(f"Successfully updated and re-vectorized summary for segment {segment.id}")
+                return summary_record
+            else:
+                # Create new summary record if doesn't exist
+                summary_record = SummaryIndexService.create_summary_record(
+                    segment, dataset, summary_content, status="generating"
+                )
+                SummaryIndexService.vectorize_summary(summary_record, segment, dataset)
+                db.session.commit()
+                logger.info(f"Successfully created and vectorized summary for segment {segment.id}")
+                return summary_record
+
+        except Exception as e:
+            logger.exception(f"Failed to update summary for segment {segment.id}: {str(e)}")
+            # Update summary record with error status if it exists
+            summary_record = (
+                db.session.query(DocumentSegmentSummary)
+                .filter_by(chunk_id=segment.id, dataset_id=dataset.id)
+                .first()
+            )
+            if summary_record:
+                summary_record.status = "error"
+                summary_record.error = str(e)
+                db.session.add(summary_record)
+                db.session.commit()
+            raise
+

api/tasks/add_document_to_index_task.py

@@ -117,6 +117,18 @@ def add_document_to_index_task(dataset_document_id: str):
         )
         db.session.commit()
 
+        # Enable summary indexes for all segments in this document
+        from services.summary_index_service import SummaryIndexService
+        segment_ids_list = [segment.id for segment in segments]
+        if segment_ids_list:
+            try:
+                SummaryIndexService.enable_summaries_for_segments(
+                    dataset=dataset,
+                    segment_ids=segment_ids_list,
+                )
+            except Exception as e:
+                logger.warning(f"Failed to enable summaries for document {dataset_document.id}: {str(e)}")
+
         end_at = time.perf_counter()
         logger.info(
             click.style(f"Document added to index: {dataset_document.id} latency: {end_at - start_at}", fg="green")

api/tasks/delete_segment_from_index_task.py

@@ -42,6 +42,7 @@ def delete_segment_from_index_task(
         doc_form = dataset_document.doc_form
 
         # Proceed with index cleanup using the index_node_ids directly
+        # For actual deletion, we should delete summaries (not just disable them)
         index_processor = IndexProcessorFactory(doc_form).init_index_processor()
         index_processor.clean(
             dataset,
@@ -49,6 +50,7 @@ def delete_segment_from_index_task(
             with_keywords=True,
             delete_child_chunks=True,
             precomputed_child_node_ids=child_node_ids,
+            delete_summaries=True,  # Actually delete summaries when segment is deleted
         )
         if dataset.is_multimodal:
             # delete segment attachment binding

api/tasks/disable_segment_from_index_task.py

@@ -53,6 +53,17 @@ def disable_segment_from_index_task(segment_id: str):
             logger.info(click.style(f"Segment {segment.id} document status is invalid, pass.", fg="cyan"))
             return
 
+        # Disable summary index for this segment
+        from services.summary_index_service import SummaryIndexService
+        try:
+            SummaryIndexService.disable_summaries_for_segments(
+                dataset=dataset,
+                segment_ids=[segment.id],
+                disabled_by=segment.disabled_by,
+            )
+        except Exception as e:
+            logger.warning(f"Failed to disable summary for segment {segment.id}: {str(e)}")
+
         index_type = dataset_document.doc_form
         index_processor = IndexProcessorFactory(index_type).init_index_processor()
         index_processor.clean(dataset, [segment.index_node_id])

api/tasks/disable_segments_from_index_task.py

@@ -58,12 +58,25 @@ def disable_segments_from_index_task(segment_ids: list, dataset_id: str, documen
         return
 
     try:
+        # Disable summary indexes for these segments
+        from services.summary_index_service import SummaryIndexService
+        segment_ids_list = [segment.id for segment in segments]
+        try:
+            # Get disabled_by from first segment (they should all have the same disabled_by)
+            disabled_by = segments[0].disabled_by if segments else None
+            SummaryIndexService.disable_summaries_for_segments(
+                dataset=dataset,
+                segment_ids=segment_ids_list,
+                disabled_by=disabled_by,
+            )
+        except Exception as e:
+            logger.warning(f"Failed to disable summaries for segments: {str(e)}")
+
         index_node_ids = [segment.index_node_id for segment in segments]
         if dataset.is_multimodal:
-            segment_ids = [segment.id for segment in segments]
             segment_attachment_bindings = (
                 db.session.query(SegmentAttachmentBinding)
-                .where(SegmentAttachmentBinding.segment_id.in_(segment_ids))
+                .where(SegmentAttachmentBinding.segment_id.in_(segment_ids_list))
                 .all()
             )
             if segment_attachment_bindings:

api/tasks/document_indexing_task.py

@@ -8,6 +8,7 @@ from celery import shared_task
 from configs import dify_config
 from core.entities.document_task import DocumentTask
 from core.indexing_runner import DocumentIsPausedError, IndexingRunner
+from tasks.generate_summary_index_task import generate_summary_index_task
 from core.rag.pipeline.queue import TenantIsolatedTaskQueue
 from enums.cloud_plan import CloudPlan
 from extensions.ext_database import db
@@ -100,6 +101,60 @@ def _document_indexing(dataset_id: str, document_ids: Sequence[str]):
         indexing_runner.run(documents)
         end_at = time.perf_counter()
         logger.info(click.style(f"Processed dataset: {dataset_id} latency: {end_at - start_at}", fg="green"))
+        
+        # Trigger summary index generation for completed documents if enabled
+        # Only generate for high_quality indexing technique and when summary_index_setting is enabled
+        # Re-query dataset to get latest summary_index_setting (in case it was updated)
+        dataset = db.session.query(Dataset).where(Dataset.id == dataset_id).first()
+        if not dataset:
+            logger.warning(f"Dataset {dataset_id} not found after indexing")
+            return
+        
+        if dataset.indexing_technique == "high_quality":
+            summary_index_setting = dataset.summary_index_setting
+            if summary_index_setting and summary_index_setting.get("enable"):
+                # Check each document's indexing status and trigger summary generation if completed
+                for document_id in document_ids:
+                    # Re-query document to get latest status (IndexingRunner may have updated it)
+                    document = (
+                        db.session.query(Document)
+                        .where(Document.id == document_id, Document.dataset_id == dataset_id)
+                        .first()
+                    )
+                    if document:
+                        logger.info(
+                            f"Checking document {document_id} for summary generation: "
+                            f"status={document.indexing_status}, doc_form={document.doc_form}"
+                        )
+                        if document.indexing_status == "completed" and document.doc_form != "qa_model":
+                            try:
+                                generate_summary_index_task.delay(dataset.id, document_id, None)
+                                logger.info(
+                                    f"Queued summary index generation task for document {document_id} "
+                                    f"in dataset {dataset.id} after indexing completed"
+                                )
+                            except Exception as e:
+                                logger.exception(
+                                    f"Failed to queue summary index generation task for document {document_id}: {str(e)}"
+                                )
+                                # Don't fail the entire indexing process if summary task queuing fails
+                        else:
+                            logger.info(
+                                f"Skipping summary generation for document {document_id}: "
+                                f"status={document.indexing_status}, doc_form={document.doc_form}"
+                            )
+                    else:
+                        logger.warning(f"Document {document_id} not found after indexing")
+            else:
+                logger.info(
+                    f"Summary index generation skipped for dataset {dataset.id}: "
+                    f"summary_index_setting.enable={summary_index_setting.get('enable') if summary_index_setting else None}"
+                )
+        else:
+            logger.info(
+                f"Summary index generation skipped for dataset {dataset.id}: "
+                f"indexing_technique={dataset.indexing_technique} (not 'high_quality')"
+            )
     except DocumentIsPausedError as ex:
         logger.info(click.style(str(ex), fg="yellow"))
     except Exception:

api/tasks/enable_segment_to_index_task.py

@@ -103,6 +103,16 @@ def enable_segment_to_index_task(segment_id: str):
         # save vector index
         index_processor.load(dataset, [document], multimodal_documents=multimodel_documents)
 
+        # Enable summary index for this segment
+        from services.summary_index_service import SummaryIndexService
+        try:
+            SummaryIndexService.enable_summaries_for_segments(
+                dataset=dataset,
+                segment_ids=[segment.id],
+            )
+        except Exception as e:
+            logger.warning(f"Failed to enable summary for segment {segment.id}: {str(e)}")
+
         end_at = time.perf_counter()
         logger.info(click.style(f"Segment enabled to index: {segment.id} latency: {end_at - start_at}", fg="green"))
     except Exception as e:

api/tasks/enable_segments_to_index_task.py

@@ -108,6 +108,17 @@ def enable_segments_to_index_task(segment_ids: list, dataset_id: str, document_i
         # save vector index
         index_processor.load(dataset, documents, multimodal_documents=multimodal_documents)
 
+        # Enable summary indexes for these segments
+        from services.summary_index_service import SummaryIndexService
+        segment_ids_list = [segment.id for segment in segments]
+        try:
+            SummaryIndexService.enable_summaries_for_segments(
+                dataset=dataset,
+                segment_ids=segment_ids_list,
+            )
+        except Exception as e:
+            logger.warning(f"Failed to enable summaries for segments: {str(e)}")
+
         end_at = time.perf_counter()
         logger.info(click.style(f"Segments enabled to index latency: {end_at - start_at}", fg="green"))
     except Exception as e:

api/tasks/generate_summary_index_task.py

@@ -0,0 +1,113 @@
+"""Async task for generating summary indexes."""
+
+import logging
+import time
+
+import click
+from celery import shared_task
+
+from extensions.ext_database import db
+from models.dataset import Dataset, DocumentSegment
+from models.dataset import Document as DatasetDocument
+from services.summary_index_service import SummaryIndexService
+
+logger = logging.getLogger(__name__)
+
+
+@shared_task(queue="dataset")
+def generate_summary_index_task(dataset_id: str, document_id: str, segment_ids: list[str] | None = None):
+    """
+    Async generate summary index for document segments.
+
+    Args:
+        dataset_id: Dataset ID
+        document_id: Document ID
+        segment_ids: Optional list of specific segment IDs to process. If None, process all segments.
+
+    Usage:
+        generate_summary_index_task.delay(dataset_id, document_id)
+        generate_summary_index_task.delay(dataset_id, document_id, segment_ids)
+    """
+    logger.info(
+        click.style(
+            f"Start generating summary index for document {document_id} in dataset {dataset_id}",
+            fg="green",
+        )
+    )
+    start_at = time.perf_counter()
+
+    try:
+        dataset = db.session.query(Dataset).where(Dataset.id == dataset_id).first()
+        if not dataset:
+            logger.error(click.style(f"Dataset not found: {dataset_id}", fg="red"))
+            db.session.close()
+            return
+
+        document = db.session.query(DatasetDocument).where(DatasetDocument.id == document_id).first()
+        if not document:
+            logger.error(click.style(f"Document not found: {document_id}", fg="red"))
+            db.session.close()
+            return
+
+        # Only generate summary index for high_quality indexing technique
+        if dataset.indexing_technique != "high_quality":
+            logger.info(
+                click.style(
+                    f"Skipping summary generation for dataset {dataset_id}: "
+                    f"indexing_technique is {dataset.indexing_technique}, not 'high_quality'",
+                    fg="cyan",
+                )
+            )
+            db.session.close()
+            return
+
+        # Check if summary index is enabled
+        summary_index_setting = dataset.summary_index_setting
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            logger.info(
+                click.style(
+                    f"Summary index is disabled for dataset {dataset_id}",
+                    fg="cyan",
+                )
+            )
+            db.session.close()
+            return
+
+        # Determine if only parent chunks should be processed
+        only_parent_chunks = dataset.chunk_structure == "parent_child_index"
+
+        # Generate summaries
+        summary_records = SummaryIndexService.generate_summaries_for_document(
+            dataset=dataset,
+            document=document,
+            summary_index_setting=summary_index_setting,
+            segment_ids=segment_ids,
+            only_parent_chunks=only_parent_chunks,
+        )
+
+        end_at = time.perf_counter()
+        logger.info(
+            click.style(
+                f"Summary index generation completed for document {document_id}: "
+                f"{len(summary_records)} summaries generated, latency: {end_at - start_at}",
+                fg="green",
+            )
+        )
+
+    except Exception as e:
+        logger.exception(f"Failed to generate summary index for document {document_id}: {str(e)}")
+        # Update document segments with error status if needed
+        if segment_ids:
+            db.session.query(DocumentSegment).filter(
+                DocumentSegment.id.in_(segment_ids),
+                DocumentSegment.dataset_id == dataset_id,
+            ).update(
+                {
+                    DocumentSegment.error: f"Summary generation failed: {str(e)}",
+                },
+                synchronize_session=False,
+            )
+            db.session.commit()
+    finally:
+        db.session.close()
+

api/tasks/regenerate_summary_index_task.py

@@ -0,0 +1,219 @@
+"""Task for regenerating summary indexes when dataset settings change."""
+
+import logging
+import time
+from typing import Any
+
+import click
+from celery import shared_task
+from sqlalchemy import select
+
+from extensions.ext_database import db
+from models.dataset import Dataset, DocumentSegment, DocumentSegmentSummary
+from models.dataset import Document as DatasetDocument
+from services.summary_index_service import SummaryIndexService
+
+logger = logging.getLogger(__name__)
+
+
+@shared_task(queue="dataset")
+def regenerate_summary_index_task(
+    dataset_id: str,
+    regenerate_reason: str = "summary_model_changed",
+    regenerate_vectors_only: bool = False,
+):
+    """
+    Regenerate summary indexes for all documents in a dataset.
+    
+    This task is triggered when:
+    1. summary_index_setting model changes (regenerate_reason="summary_model_changed")
+       - Regenerates summary content and vectors for all existing summaries
+    2. embedding_model changes (regenerate_reason="embedding_model_changed")
+       - Only regenerates vectors for existing summaries (keeps summary content)
+    
+    Args:
+        dataset_id: Dataset ID
+        regenerate_reason: Reason for regeneration ("summary_model_changed" or "embedding_model_changed")
+        regenerate_vectors_only: If True, only regenerate vectors without regenerating summary content
+    """
+    logger.info(
+        click.style(
+            f"Start regenerate summary index for dataset {dataset_id}, reason: {regenerate_reason}",
+            fg="green",
+        )
+    )
+    start_at = time.perf_counter()
+
+    try:
+        dataset = db.session.query(Dataset).filter_by(id=dataset_id).first()
+        if not dataset:
+            logger.error(click.style(f"Dataset not found: {dataset_id}", fg="red"))
+            db.session.close()
+            return
+
+        # Only regenerate summary index for high_quality indexing technique
+        if dataset.indexing_technique != "high_quality":
+            logger.info(
+                click.style(
+                    f"Skipping summary regeneration for dataset {dataset_id}: "
+                    f"indexing_technique is {dataset.indexing_technique}, not 'high_quality'",
+                    fg="cyan",
+                )
+            )
+            db.session.close()
+            return
+
+        # Check if summary index is enabled
+        summary_index_setting = dataset.summary_index_setting
+        if not summary_index_setting or not summary_index_setting.get("enable"):
+            logger.info(
+                click.style(
+                    f"Summary index is disabled for dataset {dataset_id}",
+                    fg="cyan",
+                )
+            )
+            db.session.close()
+            return
+
+        # Get all documents with completed indexing status
+        dataset_documents = db.session.scalars(
+            select(DatasetDocument).where(
+                DatasetDocument.dataset_id == dataset_id,
+                DatasetDocument.indexing_status == "completed",
+                DatasetDocument.enabled == True,
+                DatasetDocument.archived == False,
+            )
+        ).all()
+
+        if not dataset_documents:
+            logger.info(
+                click.style(
+                    f"No documents found for summary regeneration in dataset {dataset_id}",
+                    fg="cyan",
+                )
+            )
+            db.session.close()
+            return
+
+        logger.info(
+            f"Found {len(dataset_documents)} documents for summary regeneration in dataset {dataset_id}"
+        )
+
+        total_segments_processed = 0
+        total_segments_failed = 0
+
+        for dataset_document in dataset_documents:
+            # Skip qa_model documents
+            if dataset_document.doc_form == "qa_model":
+                continue
+
+            try:
+                # Get all segments with existing summaries
+                segments = (
+                    db.session.query(DocumentSegment)
+                    .join(
+                        DocumentSegmentSummary,
+                        DocumentSegment.id == DocumentSegmentSummary.chunk_id,
+                    )
+                    .where(
+                        DocumentSegment.document_id == dataset_document.id,
+                        DocumentSegment.dataset_id == dataset_id,
+                        DocumentSegment.status == "completed",
+                        DocumentSegment.enabled == True,
+                        DocumentSegmentSummary.dataset_id == dataset_id,
+                    )
+                    .order_by(DocumentSegment.position.asc())
+                    .all()
+                )
+
+                if not segments:
+                    continue
+
+                logger.info(
+                    f"Regenerating summaries for {len(segments)} segments in document {dataset_document.id}"
+                )
+
+                for segment in segments:
+                    try:
+                        # Get existing summary record
+                        summary_record = (
+                            db.session.query(DocumentSegmentSummary)
+                            .filter_by(
+                                chunk_id=segment.id,
+                                dataset_id=dataset_id,
+                            )
+                            .first()
+                        )
+
+                        if not summary_record:
+                            logger.warning(
+                                f"Summary record not found for segment {segment.id}, skipping"
+                            )
+                            continue
+
+                        if regenerate_vectors_only:
+                            # Only regenerate vectors (for embedding_model change)
+                            # Delete old vector
+                            if summary_record.summary_index_node_id:
+                                try:
+                                    from core.rag.datasource.vdb.vector_factory import Vector
+
+                                    vector = Vector(dataset)
+                                    vector.delete_by_ids([summary_record.summary_index_node_id])
+                                except Exception as e:
+                                    logger.warning(
+                                        f"Failed to delete old summary vector for segment {segment.id}: {str(e)}"
+                                    )
+
+                            # Re-vectorize with new embedding model
+                            SummaryIndexService.vectorize_summary(
+                                summary_record, segment, dataset
+                            )
+                            db.session.commit()
+                        else:
+                            # Regenerate both summary content and vectors (for summary_model change)
+                            SummaryIndexService.generate_and_vectorize_summary(
+                                segment, dataset, summary_index_setting
+                            )
+                            db.session.commit()
+
+                        total_segments_processed += 1
+
+                    except Exception as e:
+                        logger.error(
+                            f"Failed to regenerate summary for segment {segment.id}: {str(e)}",
+                            exc_info=True,
+                        )
+                        total_segments_failed += 1
+                        # Update summary record with error status
+                        if summary_record:
+                            summary_record.status = "error"
+                            summary_record.error = f"Regeneration failed: {str(e)}"
+                            db.session.add(summary_record)
+                            db.session.commit()
+                        continue
+
+            except Exception as e:
+                logger.error(
+                    f"Failed to process document {dataset_document.id} for summary regeneration: {str(e)}",
+                    exc_info=True,
+                )
+                continue
+
+        end_at = time.perf_counter()
+        logger.info(
+            click.style(
+                f"Summary index regeneration completed for dataset {dataset_id}: "
+                f"{total_segments_processed} segments processed successfully, "
+                f"{total_segments_failed} segments failed, "
+                f"total documents: {len(dataset_documents)}, "
+                f"latency: {end_at - start_at:.2f}s",
+                fg="green",
+            )
+        )
+
+    except Exception:
+        logger.exception(f"Regenerate summary index failed for dataset {dataset_id}")
+    finally:
+        db.session.close()
+

api/tasks/remove_document_from_index_task.py

@@ -47,6 +47,20 @@ def remove_document_from_index_task(document_id: str):
         index_processor = IndexProcessorFactory(document.doc_form).init_index_processor()
 
         segments = db.session.scalars(select(DocumentSegment).where(DocumentSegment.document_id == document.id)).all()
+        
+        # Disable summary indexes for all segments in this document
+        from services.summary_index_service import SummaryIndexService
+        segment_ids_list = [segment.id for segment in segments]
+        if segment_ids_list:
+            try:
+                SummaryIndexService.disable_summaries_for_segments(
+                    dataset=dataset,
+                    segment_ids=segment_ids_list,
+                    disabled_by=document.disabled_by,
+                )
+            except Exception as e:
+                logger.warning(f"Failed to disable summaries for document {document.id}: {str(e)}")
+        
         index_node_ids = [segment.index_node_id for segment in segments]
         if index_node_ids:
             try: