feat: add retireval_top_n to config in env (#11132)

api/.env.example

 # Reset password token expiry minutes
 RESET_PASSWORD_TOKEN_EXPIRY_MINUTES=5
 
-CREATE_TIDB_SERVICE_JOB_ENABLED=false
+CREATE_TIDB_SERVICE_JOB_ENABLED=false
+
+RETRIEVAL_TOP_N=0

api/configs/feature/__init__.py

         default=30,
     )
 
+    RETRIEVAL_TOP_N: int = Field(description="number of retrieval top_n", default=0)
+
 
 class WorkspaceConfig(BaseSettings):
     """

api/core/rag/datasource/retrieval_service.py

 
 from flask import Flask, current_app
 
+from configs import DifyConfig
 from core.rag.data_post_processor.data_post_processor import DataPostProcessor
 from core.rag.datasource.keyword.keyword_factory import Keyword
 from core.rag.datasource.vdb.vector_factory import Vector
                 str(dataset.tenant_id), reranking_mode, reranking_model, weights, False
             )
             all_documents = data_post_processor.invoke(
-                query=query, documents=all_documents, score_threshold=score_threshold, top_n=top_k
+                query=query,
+                documents=all_documents,
+                score_threshold=score_threshold,
+                top_n=DifyConfig.RETRIEVAL_TOP_N or top_k,
             )
+
         return all_documents
 
     @classmethod
                         )
                         all_documents.extend(
                             data_post_processor.invoke(
-                                query=query, documents=documents, score_threshold=score_threshold, top_n=len(documents)
+                                query=query,
+                                documents=documents,
+                                score_threshold=score_threshold,
+                                top_n=DifyConfig.RETRIEVAL_TOP_N or len(documents),
                             )
                         )
                     else:
                         )
                         all_documents.extend(
                             data_post_processor.invoke(
-                                query=query, documents=documents, score_threshold=score_threshold, top_n=len(documents)
+                                query=query,
+                                documents=documents,
+                                score_threshold=score_threshold,
+                                top_n=DifyConfig.RETRIEVAL_TOP_N or len(documents),
                             )
                         )
                     else:

docker/docker-compose.yaml

   OCEANBASE_CLUSTER_NAME: ${OCEANBASE_CLUSTER_NAME:-difyai}
   OCEANBASE_MEMORY_LIMIT: ${OCEANBASE_MEMORY_LIMIT:-6G}
   CREATE_TIDB_SERVICE_JOB_ENABLED: ${CREATE_TIDB_SERVICE_JOB_ENABLED:-false}
+  RETRIEVAL_TOP_N: ${RETRIEVAL_TOP_N:-0}
 
 services:
   # API service