fix SQL slow query (#2043)

Co-authored-by: jyong <jyong@dify.ai>

api/core/tool/dataset_multi_retriever_tool.py

@@ -94,6 +94,7 @@ class DatasetMultiRetrieverTool(BaseTool):
         document_context_list = []
         index_node_ids = [document.metadata['doc_id'] for document in all_documents]
         segments = DocumentSegment.query.filter(
+            DocumentSegment.dataset_id.in_(self.dataset_ids),
             DocumentSegment.completed_at.isnot(None),
             DocumentSegment.status == 'completed',
             DocumentSegment.enabled == True,