diff --git a/cpp/unittest/db/db_tests.cpp b/cpp/unittest/db/db_tests.cpp
index fe97a9d66b..4b873db20d 100644
--- a/cpp/unittest/db/db_tests.cpp
+++ b/cpp/unittest/db/db_tests.cpp
@@ -59,6 +59,7 @@ TEST_F(DBTest, DB_TEST) {
 
     engine::Options opt;
     opt.memory_sync_interval = 1;
+    opt.index_trigger_size = 1024*group_dim;
     opt.meta.backend_uri = "http://127.0.0.1";
     opt.meta.path = "/tmp/vecwise_test/db_test";
 
@@ -81,7 +82,7 @@ TEST_F(DBTest, DB_TEST) {
     engine::IDNumbers target_ids;
 
     int d = 256;
-    int nb = 5;
+    int nb = 100;
     float *xb = new float[d * nb];
     for(int i = 0; i < nb; i++) {
         for(int j = 0; j < d; j++) xb[d * i + j] = drand48();
@@ -95,7 +96,33 @@ TEST_F(DBTest, DB_TEST) {
         qxb[d * i] += i / 2000.;
     }
 
-    int loop = 2000000;
+    std::thread search([&]() {
+        engine::QueryResults results;
+        int k = 10;
+        std::this_thread::sleep_for(std::chrono::seconds(2));
+        /* std::this_thread::sleep_for(std::chrono::milliseconds(30)); */
+
+        INIT_TIMER;
+        std::stringstream ss;
+        long count = 0;
+
+        for (auto j=0; j<5; ++j) {
+            ss.str("");
+            db->count(group_name, count);
+
+            ss << "Search " << j << " With Size " << count;
+
+            START_TIMER;
+            stat = db->search(group_name, k, qb, qxb, results);
+            STOP_TIMER(ss.str());
+
+            ASSERT_STATS(stat);
+            ASSERT_EQ(results[0][0], target_ids[0]);
+            std::this_thread::sleep_for(std::chrono::seconds(1));
+        }
+    });
+
+    int loop = 40000;
 
     for (auto i=0; i<loop; ++i) {
         if (i==40) {
@@ -103,30 +130,10 @@ TEST_F(DBTest, DB_TEST) {
         } else {
             db->add_vectors(group_name, nb, xb, vector_ids);
         }
+        std::this_thread::sleep_for(std::chrono::microseconds(100));
     }
 
-    engine::QueryResults results;
-    int k = 10;
-    std::this_thread::sleep_for(std::chrono::seconds(2));
-    INIT_TIMER;
-
-    std::stringstream ss;
-    long count = 0;
-
-    for (auto j=0; j<15; ++j) {
-        ss.str("");
-        db->count(group_name, count);
-
-        ss << "Search " << j << " With Size " << count;
-
-        START_TIMER;
-        stat = db->search(group_name, k, qb, qxb, results);
-        STOP_TIMER(ss.str());
-
-        ASSERT_STATS(stat);
-        ASSERT_EQ(results[0][0], target_ids[0]);
-        std::this_thread::sleep_for(std::chrono::seconds(1));
-    }
+    search.join();
 
     delete [] xb;
     delete [] qxb;