diff --git a/core/src/db/meta/MetaAdapter.h b/core/src/db/meta/MetaAdapter.h
index 7a906e6454a97b7042ee1280d8282c78b636402d..b5d97a79b4df9dd3314ce097adbf7371ec1ba063 100644
--- a/core/src/db/meta/MetaAdapter.h
+++ b/core/src/db/meta/MetaAdapter.h
@@ -73,7 +73,7 @@ class MetaAdapter {
 
     template <typename ResourceT>
     Status
-    Apply(snapshot::ResourceContextPtr<ResourceT> resp, int64_t& result_id) {
+    Execute(snapshot::ResourceContextPtr<ResourceT> resp, int64_t& result_id) {
         auto session = CreateSession();
         STATUS_CHECK(session->Apply<ResourceT>(resp));
 
@@ -81,7 +81,7 @@ class MetaAdapter {
         STATUS_CHECK(session->Commit(result_ids));
 
         if (result_ids.size() != 1) {
-            return Status(DB_ERROR, "Result id is wrong");
+            return Status(DB_ERROR, "Result id size is wrong");
         }
 
         result_id = result_ids.at(0);
diff --git a/core/src/db/meta/MetaFactory.h b/core/src/db/meta/MetaFactory.h
index 8d830e4dcdf40ca75bd5398f4c8b004646682fee..32af4e481e9b390665f6cc587a3958160a83346f 100644
--- a/core/src/db/meta/MetaFactory.h
+++ b/core/src/db/meta/MetaFactory.h
@@ -16,8 +16,7 @@
 #include "db/Options.h"
 #include "db/meta/MetaAdapter.h"
 
-namespace milvus {
-namespace engine {
+namespace milvus::engine {
 
 class MetaFactory {
  public:
@@ -28,5 +27,4 @@ class MetaFactory {
     Build(const DBMetaOptions& meta_options);
 };
 
-}  // namespace engine
-}  // namespace milvus
+}  // namespace milvus::engine
diff --git a/core/src/db/meta/backend/MySQLConnectionPool.cpp b/core/src/db/meta/backend/MySQLConnectionPool.cpp
index 336af74bf3a83588514bf139518d8a03c701e36c..737c9fc83b7bae3feb1da1c59d5e81bb7ee80c06 100644
--- a/core/src/db/meta/backend/MySQLConnectionPool.cpp
+++ b/core/src/db/meta/backend/MySQLConnectionPool.cpp
@@ -31,9 +31,21 @@ MySQLConnectionPool::grab() {
         full_.wait(lock, [this] { return conns_in_use_ < max_pool_size_; });
         ++conns_in_use_;
     }
+    full_.notify_one();
     return mysqlpp::ConnectionPool::grab();
 }
 
+mysqlpp::Connection*
+MySQLConnectionPool::safe_grab() {
+    {
+        std::unique_lock<std::mutex> lock(mutex_);
+        full_.wait(lock, [this] { return conns_in_use_ < max_pool_size_; });
+        ++conns_in_use_;
+    }
+    full_.notify_one();
+    return mysqlpp::ConnectionPool::safe_grab();
+}
+
 // Other half of in-use conn count limit
 void
 MySQLConnectionPool::release(const mysqlpp::Connection* pc) {
diff --git a/core/src/db/meta/backend/MySQLConnectionPool.h b/core/src/db/meta/backend/MySQLConnectionPool.h
index 4ef04d659b7334d725ee4c59a938928b5a3720ef..a3df420f0bcd08dafeb36491cadb5a9efa73cb27 100644
--- a/core/src/db/meta/backend/MySQLConnectionPool.h
+++ b/core/src/db/meta/backend/MySQLConnectionPool.h
@@ -44,6 +44,9 @@ class MySQLConnectionPool : public mysqlpp::ConnectionPool {
     mysqlpp::Connection*
     grab() override;
 
+    mysqlpp::Connection*
+    safe_grab() override;
+
     // Other half of in-use conn count limit
     void
     release(const mysqlpp::Connection* pc) override;
diff --git a/core/src/db/meta/backend/MySqlEngine.cpp b/core/src/db/meta/backend/MySqlEngine.cpp
index 36306fb6a65bd9dece4c91a913c6db7984ce665c..10c47260b074ab401628dacef1eb774547e103df 100644
--- a/core/src/db/meta/backend/MySqlEngine.cpp
+++ b/core/src/db/meta/backend/MySqlEngine.cpp
@@ -12,6 +12,7 @@
 #include "db/meta/backend/MySqlEngine.h"
 
 #include <memory>
+#include <sstream>
 #include <string>
 #include <thread>
 #include <utility>
@@ -208,25 +209,33 @@ MySqlEngine::Initialize() {
 
 Status
 MySqlEngine::Query(const MetaQueryContext& context, AttrsMapList& attrs) {
+    auto status = Status::OK();
+    mysqlpp::Connection::thread_start();
+
     try {
         mysqlpp::ScopedConnection connectionPtr(*mysql_connection_pool_, safe_grab_);
         if (connectionPtr == nullptr || !connectionPtr->connected()) {
+            mysqlpp::Connection::thread_end();
             return Status(SS_TIMEOUT, "Mysql server is not accessed");
         }
 
         std::string sql;
-        auto status = MetaHelper::MetaQueryContextToSql(context, sql);
+        status = MetaHelper::MetaQueryContextToSql(context, sql);
         if (!status.ok()) {
+            mysqlpp::Connection::thread_end();
             return status;
         }
 
-        std::lock_guard<std::mutex> lock(meta_mutex_);
-
+        // std::lock_guard<std::mutex> lock(meta_mutex_);
         mysqlpp::Query query = connectionPtr->query(sql);
         auto res = query.store();
         if (!res) {
-            // TODO: change error behavior
-            throw Exception(1, "Query res is false");
+            mysqlpp::Connection::thread_end();
+            std::stringstream ss;
+            ss << "Mysql query fail: (" << query.errnum() << ": " << query.error() << ")";
+            std::string err_msg = ss.str();
+            LOG_ENGINE_ERROR_ << err_msg;
+            return Status(DB_ERROR, err_msg);
         }
 
         auto names = res.field_names();
@@ -238,48 +247,61 @@ MySqlEngine::Query(const MetaQueryContext& context, AttrsMapList& attrs) {
             attrs.push_back(attrs_map);
         }
     } catch (const mysqlpp::ConnectionFailed& er) {
-        return Status(SS_TIMEOUT, er.what());
+        status = Status(SS_TIMEOUT, er.what());
     } catch (const mysqlpp::BadQuery& er) {
         LOG_ENGINE_ERROR_ << "Query error: " << er.what();
         if (er.errnum() == 2006) {
-            return Status(SS_TIMEOUT, er.what());
+            status = Status(SS_TIMEOUT, er.what());
+        } else {
+            status = Status(DB_ERROR, er.what());
         }
-        return Status(1, er.what());
     } catch (const mysqlpp::BadConversion& er) {
         // Handle bad conversions
         //        cerr << "Conversion error: " << er.what() << endl <<
         //             "\tretrieved data size: " << er.retrieved <<
         //             ", actual size: " << er.actual_size << endl;
-        return Status(1, er.what());
+        status = Status(DB_ERROR, er.what());
     } catch (const mysqlpp::Exception& er) {
         // Catch-all for any other MySQL++ exceptions
         //        cerr << "Error: " << er.what() << endl;
-        return Status(1, er.what());
+        status = Status(DB_ERROR, er.what());
     }
 
-    return Status::OK();
+    mysqlpp::Connection::thread_end();
+    return status;
 }
 
 Status
 MySqlEngine::ExecuteTransaction(const std::vector<MetaApplyContext>& sql_contexts, std::vector<int64_t>& result_ids) {
+    Status status;
+    mysqlpp::Connection::thread_start();
+
     try {
         mysqlpp::ScopedConnection connectionPtr(*mysql_connection_pool_, safe_grab_);
         if (connectionPtr == nullptr || !connectionPtr->connected()) {
+            mysqlpp::Connection::thread_end();
             return Status(SS_TIMEOUT, "Mysql server is not accessed");
         }
 
         mysqlpp::Transaction trans(*connectionPtr, mysqlpp::Transaction::serializable, mysqlpp::Transaction::session);
 
-        std::lock_guard<std::mutex> lock(meta_mutex_);
+        // std::lock_guard<std::mutex> lock(meta_mutex_);
         for (auto& context : sql_contexts) {
             std::string sql;
-            auto status = MetaHelper::MetaApplyContextToSql(context, sql);
+            status = MetaHelper::MetaApplyContextToSql(context, sql);
             if (!status.ok()) {
-                return status;
+                break;
             }
 
             auto query = connectionPtr->query(sql);
             auto res = query.execute();
+            if (!res) {
+                std::stringstream ss;
+                ss << "Mysql execute fail: (" << query.errnum() << ": " << query.error() << ")";
+                status = Status(DB_ERROR, ss.str());
+                break;
+            }
+
             if (context.op_ == oAdd) {
                 auto id = res.insert_id();
                 result_ids.push_back(id);
@@ -288,15 +310,20 @@ MySqlEngine::ExecuteTransaction(const std::vector<MetaApplyContext>& sql_context
             }
         }
 
-        trans.commit();
+        if (status.ok()) {
+            trans.commit();
+        } else {
+            trans.rollback();
+        }
     } catch (const mysqlpp::ConnectionFailed& er) {
-        return Status(SS_TIMEOUT, er.what());
+        status = Status(SS_TIMEOUT, er.what());
     } catch (const mysqlpp::BadQuery& er) {
         LOG_ENGINE_ERROR_ << "MySql Error Code: " << er.errnum() << ": " << er.what();
         if (er.errnum() == 2006) {
-            return Status(SS_TIMEOUT, er.what());
+            status = Status(SS_TIMEOUT, er.what());
+        } else {
+            status = Status(DB_ERROR, er.what());
         }
-        return Status(SERVER_UNSUPPORTED_ERROR, er.what());
     } catch (const mysqlpp::BadConversion& er) {
         // Handle bad conversions
         //        cerr << "Conversion error: " << er.what() << endl <<
@@ -304,16 +331,17 @@ MySqlEngine::ExecuteTransaction(const std::vector<MetaApplyContext>& sql_context
         //             ", actual size: " << er.actual_size << endl;
         //        return -1;
         //        std::cout << "[DB] Error: " << er.what() << std::endl;
-        return Status(SERVER_UNSUPPORTED_ERROR, er.what());
+        status = Status(DB_ERROR, er.what());
     } catch (const mysqlpp::Exception& er) {
         // Catch-all for any other MySQL++ exceptions
         //        cerr << "Error: " << er.what() << endl;
         //        return -1;
         //        std::cout << "[DB] Error: " << er.what() << std::endl;
-        return Status(SERVER_UNSUPPORTED_ERROR, er.what());
+        status = Status(DB_ERROR, er.what());
     }
 
-    return Status::OK();
+    mysqlpp::Connection::thread_end();
+    return status;
 }
 
 Status
diff --git a/core/src/db/snapshot/ResourceContext.h b/core/src/db/snapshot/ResourceContext.h
index 4de6988838426967e1d7b9bdbab4a05b0c50130a..1179330a2e418ab32e7d8a490f3ad075d68eb3b8 100644
--- a/core/src/db/snapshot/ResourceContext.h
+++ b/core/src/db/snapshot/ResourceContext.h
@@ -102,7 +102,6 @@ class ResourceContextBuilder {
     SetResource(typename T::Ptr res) {
         table_ = T::Name;
         id_ = res->GetID();
-        //        resource_ = std::shared_ptr<T>(std::move(res));
         resource_ = std::move(res);
         return *this;
     }
diff --git a/core/src/db/snapshot/Store.h b/core/src/db/snapshot/Store.h
index 0b4303481e217f459877e104333a93057b766c3d..f4bbb761e566464ee32050eccb87dab2b62571eb 100644
--- a/core/src/db/snapshot/Store.h
+++ b/core/src/db/snapshot/Store.h
@@ -44,9 +44,7 @@
 #include <utility>
 #include <vector>
 
-namespace milvus {
-namespace engine {
-namespace snapshot {
+namespace milvus::engine::snapshot {
 
 class Store;
 struct ApplyContext {
@@ -186,7 +184,7 @@ class Store : public std::enable_shared_from_this<Store> {
             ResourceContextBuilder<ResourceT>().SetTable(ResourceT::Name).SetOp(meta::oDelete).SetID(id).CreatePtr();
 
         int64_t result_id;
-        return adapter_->Apply<ResourceT>(rc_ctx_p, result_id);
+        return adapter_->Execute<ResourceT>(rc_ctx_p, result_id);
     }
 
     IDS_TYPE
@@ -230,7 +228,7 @@ class Store : public std::enable_shared_from_this<Store> {
         auto res_ctx_p = ResourceContextBuilder<ResourceT>().SetOp(meta::oAdd).SetResource(res_p).CreatePtr();
 
         int64_t result_id;
-        auto status = adapter_->Apply<ResourceT>(res_ctx_p, result_id);
+        auto status = adapter_->Execute<ResourceT>(res_ctx_p, result_id);
         if (!status.ok()) {
             return status;
         }
@@ -376,7 +374,7 @@ class Store : public std::enable_shared_from_this<Store> {
                                  .AddAttr(meta::F_STATE)
                                  .CreatePtr();
 
-                adapter_->Apply<Collection>(t_c_p, result_id);
+                adapter_->Execute<Collection>(t_c_p, result_id);
             } else if (record.type() == typeid(std::shared_ptr<CollectionCommit>)) {
                 const auto& r = std::any_cast<std::shared_ptr<CollectionCommit>>(record);
                 r->Activate();
@@ -385,7 +383,7 @@ class Store : public std::enable_shared_from_this<Store> {
                                   .SetResource(r)
                                   .AddAttr(meta::F_STATE)
                                   .CreatePtr();
-                adapter_->Apply<CollectionCommit>(t_cc_p, result_id);
+                adapter_->Execute<CollectionCommit>(t_cc_p, result_id);
             }
         }
     }
@@ -396,6 +394,4 @@ class Store : public std::enable_shared_from_this<Store> {
 };
 
 using StorePtr = Store::Ptr;
-}  // namespace snapshot
-}  // namespace engine
-}  // namespace milvus
+}  // namespace milvus::engine::snapshot
diff --git a/core/unittest/db/CMakeLists.txt b/core/unittest/db/CMakeLists.txt
index 27df0616b1af8a8613fe8b34169e26718192876f..ea08ca74cc2d3ead4bfd56178d18f2a1b97c08c8 100644
--- a/core/unittest/db/CMakeLists.txt
+++ b/core/unittest/db/CMakeLists.txt
@@ -15,7 +15,7 @@ set( TEST_FILES ${CMAKE_CURRENT_SOURCE_DIR}/utils.cpp
                 ${CMAKE_CURRENT_SOURCE_DIR}/test_snapshot.cpp
                 ${CMAKE_CURRENT_SOURCE_DIR}/test_segment.cpp
                 ${CMAKE_CURRENT_SOURCE_DIR}/test_db.cpp
-                ${CMAKE_CURRENT_SOURCE_DIR}/test_ss_meta.cpp
+                ${CMAKE_CURRENT_SOURCE_DIR}/test_meta.cpp
                 ${CMAKE_CURRENT_SOURCE_DIR}/test_ss_job.cpp
                 ${CMAKE_CURRENT_SOURCE_DIR}/test_ss_task.cpp
                 ${CMAKE_CURRENT_SOURCE_DIR}/test_ss_event.cpp
diff --git a/core/unittest/db/test_ss_meta.cpp b/core/unittest/db/test_meta.cpp
similarity index 53%
rename from core/unittest/db/test_ss_meta.cpp
rename to core/unittest/db/test_meta.cpp
index cb275984e7ca8d975f07bc7161c9da7b02bf3482..8b7c759f82f4bab2e7662d1d78ec9d8dafdc0043 100644
--- a/core/unittest/db/test_ss_meta.cpp
+++ b/core/unittest/db/test_meta.cpp
@@ -13,22 +13,24 @@
 #include "db/meta/backend/MetaContext.h"
 #include "db/snapshot/ResourceContext.h"
 #include "db/utils.h"
+#include "utils/Json.h"
 
-template <typename T>
+template<typename T>
 using ResourceContext = milvus::engine::snapshot::ResourceContext<T>;
-template <typename T>
+template<typename T>
 using ResourceContextBuilder = milvus::engine::snapshot::ResourceContextBuilder<T>;
 
 using FType = milvus::engine::DataType;
 using FEType = milvus::engine::FieldElementType;
 using Op = milvus::engine::meta::MetaContextOp;
+using State = milvus::engine::snapshot::State;
 
 TEST_F(MetaTest, ApplyTest) {
     ID_TYPE result_id;
 
     auto collection = std::make_shared<Collection>("meta_test_c1");
     auto c_ctx = ResourceContextBuilder<Collection>().SetResource(collection).CreatePtr();
-    auto status = meta_->Apply<Collection>(c_ctx, result_id);
+    auto status = meta_->Execute<Collection>(c_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     collection->SetID(result_id);
@@ -36,13 +38,13 @@ TEST_F(MetaTest, ApplyTest) {
     collection->Activate();
     auto c2_ctx = ResourceContextBuilder<Collection>().SetResource(collection)
         .SetOp(Op::oUpdate).AddAttr(milvus::engine::meta::F_STATE).CreatePtr();
-    status = meta_->Apply<Collection>(c2_ctx, result_id);
+    status = meta_->Execute<Collection>(c2_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     ASSERT_EQ(result_id, collection->GetID());
 
     auto c3_ctx = ResourceContextBuilder<Collection>().SetID(result_id).SetOp(Op::oDelete).CreatePtr();
-    status = meta_->Apply<Collection>(c3_ctx, result_id);
+    status = meta_->Execute<Collection>(c3_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     ASSERT_EQ(result_id, collection->GetID());
@@ -53,29 +55,29 @@ TEST_F(MetaTest, SessionTest) {
 
     auto collection = std::make_shared<Collection>("meta_test_c1");
     auto c_ctx = ResourceContextBuilder<Collection>().SetResource(collection).CreatePtr();
-    auto status = meta_->Apply<Collection>(c_ctx, result_id);
+    auto status = meta_->Execute<Collection>(c_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     collection->SetID(result_id);
 
     auto partition = std::make_shared<Partition>("meta_test_p1", result_id);
     auto p_ctx = ResourceContextBuilder<Partition>().SetResource(partition).CreatePtr();
-    status = meta_->Apply<Partition>(p_ctx, result_id);
+    status = meta_->Execute<Partition>(p_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     partition->SetID(result_id);
 
     auto field = std::make_shared<Field>("meta_test_f1", 1, FType::INT64);
     auto f_ctx = ResourceContextBuilder<Field>().SetResource(field).CreatePtr();
-    status = meta_->Apply<Field>(f_ctx, result_id);
+    status = meta_->Execute<Field>(f_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     field->SetID(result_id);
 
     auto field_element = std::make_shared<FieldElement>(collection->GetID(), field->GetID(),
-        "meta_test_f1_fe1", FEType::FET_RAW);
+                                                        "meta_test_f1_fe1", FEType::FET_RAW);
     auto fe_ctx = ResourceContextBuilder<FieldElement>().SetResource(field_element).CreatePtr();
-    status = meta_->Apply<FieldElement>(fe_ctx, result_id);
+    status = meta_->Execute<FieldElement>(fe_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     field_element->SetID(result_id);
@@ -121,7 +123,7 @@ TEST_F(MetaTest, SelectTest) {
     auto collection = std::make_shared<Collection>("meta_test_c1");
     ASSERT_TRUE(collection->Activate());
     auto c_ctx = ResourceContextBuilder<Collection>().SetResource(collection).CreatePtr();
-    auto status = meta_->Apply<Collection>(c_ctx, result_id);
+    auto status = meta_->Execute<Collection>(c_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     collection->SetID(result_id);
@@ -135,7 +137,7 @@ TEST_F(MetaTest, SelectTest) {
     auto collection2 = std::make_shared<Collection>("meta_test_c2");
     ASSERT_TRUE(collection2->Activate());
     auto c2_ctx = ResourceContextBuilder<Collection>().SetResource(collection2).CreatePtr();
-    status = meta_->Apply<Collection>(c2_ctx, result_id);
+    status = meta_->Execute<Collection>(c2_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     collection2->SetID(result_id);
@@ -144,7 +146,7 @@ TEST_F(MetaTest, SelectTest) {
 
     std::vector<Collection::Ptr> return_collections;
     status = meta_->SelectBy<Collection, ID_TYPE>(milvus::engine::meta::F_ID,
-        {collection2->GetID()}, return_collections);
+                                                  {collection2->GetID()}, return_collections);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_EQ(return_collections.size(), 1);
     ASSERT_EQ(return_collections.at(0)->GetID(), collection2->GetID());
@@ -174,7 +176,7 @@ TEST_F(MetaTest, TruncateTest) {
     auto collection = std::make_shared<Collection>("meta_test_c1");
     ASSERT_TRUE(collection->Activate());
     auto c_ctx = ResourceContextBuilder<Collection>().SetResource(collection).CreatePtr();
-    auto status = meta_->Apply<Collection>(c_ctx, result_id);
+    auto status = meta_->Execute<Collection>(c_ctx, result_id);
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_GT(result_id, 0);
     collection->SetID(result_id);
@@ -187,3 +189,117 @@ TEST_F(MetaTest, TruncateTest) {
     ASSERT_TRUE(status.ok()) << status.ToString();
     ASSERT_EQ(return_collection, nullptr);
 }
+
+TEST_F(MetaTest, MultiThreadRequestTest) {
+    auto request_worker = [&](size_t i) {
+        std::string collection_name_prefix = "meta_test_collection_" + std::to_string(i) + "_";
+        int64_t result_id;
+        for (size_t ii = 0; ii < 30; ii++) {
+            std::string collection_name = collection_name_prefix + std::to_string(ii);
+            auto collection = std::make_shared<Collection>(collection_name);
+            auto c_ctx = ResourceContextBuilder<Collection>().SetResource(collection).CreatePtr();
+            auto status = meta_->Execute<Collection>(c_ctx, result_id);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+            ASSERT_GT(result_id, 0);
+
+            collection->SetID(result_id);
+            collection->Activate();
+            auto c_ctx2 = ResourceContextBuilder<Collection>().SetResource(collection)
+                .SetOp(Op::oUpdate).AddAttr(milvus::engine::meta::F_STATE).CreatePtr();
+            status = meta_->Execute<Collection>(c_ctx2, result_id);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+
+            CollectionPtr collection2;
+            status = meta_->Select<Collection>(result_id, collection2);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+            ASSERT_EQ(collection2->GetID(), result_id);
+            ASSERT_EQ(collection2->GetState(), State::ACTIVE);
+            ASSERT_EQ(collection2->GetName(), collection_name);
+
+            collection->Deactivate();
+            auto c_ctx3 = ResourceContextBuilder<Collection>().SetResource(collection)
+                .SetOp(Op::oUpdate).AddAttr(milvus::engine::meta::F_STATE).CreatePtr();
+            status = meta_->Execute<Collection>(c_ctx3, result_id);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+            ASSERT_EQ(result_id, collection->GetID());
+
+            auto c_ctx4 = ResourceContextBuilder<Collection>().SetID(result_id)
+                .SetOp(Op::oDelete).SetTable(Collection::Name).CreatePtr();
+            status = meta_->Execute<Collection>(c_ctx4, result_id);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+            CollectionPtr collection3;
+            status = meta_->Select<Collection>(result_id, collection3);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+            ASSERT_EQ(collection3, nullptr);
+        }
+    };
+
+    auto cc_task = [&](size_t j) {
+        std::string collection_name_prefix = "meta_test_collection_cc_" + std::to_string(j) + "_";
+        int64_t result_id;
+        Status status;
+        for (size_t jj = 0; jj < 20; jj ++) {
+            std::string collection_name = collection_name_prefix + std::to_string(jj);
+            milvus::json cj{{"segment_row_count", 1024}};
+            auto collection = std::make_shared<Collection>(collection_name, cj);
+            auto c_ctx = ResourceContextBuilder<Collection>().SetResource(collection).SetOp(Op::oAdd).CreatePtr();
+            status = meta_->Execute<Collection>(c_ctx, result_id);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+            ASSERT_GT(result_id, 0);
+            collection->SetID(result_id);
+
+            std::string partition_name = collection_name + "_p_" + std::to_string(jj);
+            auto partition = std::make_shared<Partition>(partition_name, collection->GetID());
+            auto p_ctx = ResourceContextBuilder<Partition>().SetResource(partition).SetOp(Op::oAdd).CreatePtr();
+            status = meta_->Execute<Partition>(p_ctx, result_id);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+            ASSERT_GT(result_id, 0);
+            partition->SetID(result_id);
+
+            std::string segment_name = partition_name + "_s_" + std::to_string(jj);
+            auto segment = std::make_shared<Segment>(collection->GetID(), partition->GetID());
+            auto s_ctx = ResourceContextBuilder<Segment>().SetResource(segment).SetOp(Op::oAdd).CreatePtr();
+            status = meta_->Execute<Segment>(s_ctx, result_id);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+            ASSERT_GT(result_id, 0);
+            segment->SetID(result_id);
+
+            auto session = meta_->CreateSession();
+
+            collection->Activate();
+            auto c_ctx2 = ResourceContextBuilder<Collection>().SetResource(collection)
+                .SetOp(Op::oUpdate).AddAttr(milvus::engine::meta::F_STATE).CreatePtr();
+            ASSERT_TRUE(session->Apply<Collection>(c_ctx2).ok());
+            partition->Activate();
+            auto p_ctx2 = ResourceContextBuilder<Partition>().SetResource(partition)
+                .SetOp(Op::oUpdate).AddAttr(milvus::engine::meta::F_STATE).CreatePtr();
+            ASSERT_TRUE(session->Apply<Partition>(p_ctx2).ok());
+            segment->Activate();
+            auto s_ctx2 = ResourceContextBuilder<Segment>().SetResource(segment)
+                .SetOp(Op::oUpdate).AddAttr(milvus::engine::meta::F_STATE).CreatePtr();
+            ASSERT_TRUE(session->Apply<Segment>(s_ctx2).ok());
+            std::vector<int64_t> ids;
+            status = session->Commit(ids);
+            ASSERT_TRUE(status.ok()) << status.ToString();
+        }
+    };
+
+    unsigned int thread_hint = std::thread::hardware_concurrency();
+    std::vector<std::thread> request_threads;
+    for (size_t i = 0; i < 3 * thread_hint; i++) {
+        request_threads.emplace_back(request_worker, i);
+    }
+
+    std::vector<std::thread> cc_threads;
+    for (size_t j = 0; j < 3 * thread_hint; j++) {
+        cc_threads.emplace_back(cc_task, j);
+    }
+
+    for (auto& t : request_threads) {
+        t.join();
+    }
+
+    for (auto& t : cc_threads) {
+        t.join();
+    }
+}
diff --git a/core/unittest/db/utils.cpp b/core/unittest/db/utils.cpp
index fb239fb8b481921869f3900f94ca1b242b44f009..1e6a1338984b68a564123a15da014f94cffbdf86 100644
--- a/core/unittest/db/utils.cpp
+++ b/core/unittest/db/utils.cpp
@@ -300,7 +300,7 @@ void
 MetaTest::SetUp() {
     auto engine = std::make_shared<milvus::engine::meta::MockEngine>();
 //    milvus::engine::DBMetaOptions options;
-//    options.backend_uri_ = "mysql://root:12345678@127.0.0.1:3307/milvus";
+//    options.backend_uri_ = "mysql://root:12345678@127.0.0.1:3309/milvus";
 //    auto engine = std::make_shared<milvus::engine::meta::MySqlEngine>(options);
     meta_ = std::make_shared<milvus::engine::meta::MetaAdapter>(engine);
     meta_->TruncateAll();