#2692 Milvus hangs during multi-thread concurrent search (#2715)

* #2642 Create index failed caused by server crashed.
Signed-off-by: Nyhmo <yihua.mo@zilliz.com>

* changelog
Signed-off-by: Nyhmo <yihua.mo@zilliz.com>

* changelog
Signed-off-by: Nyhmo <yihua.mo@zilliz.com>

* typo
Signed-off-by: Nyhmo <yihua.mo@zilliz.com>

* #2692 Milvus hangs during multi-thread concurrent search
Signed-off-by: Nyhmo <yihua.mo@zilliz.com>

CHANGELOG.md

@@ -14,6 +14,7 @@ Please mark all change in change log and use the issue from GitHub
 -   \#2637 Suit the range of HNSW parameters
 -   \#2642 Create index failed and server crashed
 -   \#2649 Search parameter of annoy has conflict with document
+-   \#2692 Milvus hangs during multi-thread concurrent search
 
 ## Feature
 

core/src/server/delivery/request/BaseRequest.cpp

@@ -127,6 +127,7 @@ BaseRequest::OnPostExecute() {
 
 void
 BaseRequest::Done() {
+    std::unique_lock<std::mutex> lock(finish_mtx_);
     done_ = true;
     finish_cond_.notify_all();
 }

core/src/server/delivery/request/BaseRequest.h

@@ -211,15 +211,16 @@ class BaseRequest {
  protected:
     const std::shared_ptr<milvus::server::Context> context_;
 
-    mutable std::mutex finish_mtx_;
-    std::condition_variable finish_cond_;
-
     RequestType type_;
     std::string request_group_;
     bool async_;
-    bool done_;
     Status status_;
 
+ private:
+    mutable std::mutex finish_mtx_;
+    std::condition_variable finish_cond_;
+    bool done_;
+
  public:
     const std::shared_ptr<milvus::server::Context>&
     Context() const {