diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1cc5e137276239805f194b813e460e601f4ba452..be14477abae0ab3703e314becbb596b84b528b12 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ Please mark all change in change log and use the issue from GitHub
 -   \#1832 Fix crash in tracing module
 -   \#1873 Fix index file serialize to incorrect path
 -   \#1881 Fix bad alloc when index files lost
+-   \#1901 Search failed with flat index
 -   \#1903 Fix invalid annoy result
 -   \#1910 C++ SDK GetIDsInSegment could not work for large dataset
 
diff --git a/core/src/scheduler/optimizer/FaissFlatPass.cpp b/core/src/scheduler/optimizer/FaissFlatPass.cpp
index c0fb4780ad00db193883dd43160190b033f88574..b2edaa1ccaeb7a57f7f32ac5abc0c59c42e859ca 100644
--- a/core/src/scheduler/optimizer/FaissFlatPass.cpp
+++ b/core/src/scheduler/optimizer/FaissFlatPass.cpp
@@ -63,7 +63,7 @@ FaissFlatPass::Run(const TaskPtr& task) {
     } else {
         auto best_device_id = count_ % search_gpus_.size();
         SERVER_LOG_DEBUG << LogOut("[%s][%d] FaissFlatPass: nq > gpu_search_threshold, specify gpu %d to search!",
-                                   best_device_id, "search", 0);
+                                   "search", 0, best_device_id);
         ++count_;
         res_ptr = ResMgrInst::GetInstance()->GetResource(ResourceType::GPU, search_gpus_[best_device_id]);
     }