diff --git a/CHANGELOG.md b/CHANGELOG.md
index fcd51d1f45..42d5b8978f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,8 @@ Please mark all change in change log and use the ticket from JIRA.
 - \#322 - Add option to enable / disable prometheus
 - \#358 - Add more information in build.sh and install.md
 - \#255 - Add ivfsq8 test report detailed version
+- \#404 - Add virtual method Init() in Pass abstract class
+- \#409 - Add a Fallback pass in optimizer
 
 ## Task
 
diff --git a/ci/jenkins/step/deploySingle2Dev.groovy b/ci/jenkins/step/deploySingle2Dev.groovy
index f1daaf22ec..7b479ff44a 100644
--- a/ci/jenkins/step/deploySingle2Dev.groovy
+++ b/ci/jenkins/step/deploySingle2Dev.groovy
@@ -3,11 +3,7 @@ sh 'helm repo update'
 dir ('milvus-helm') {
     checkout([$class: 'GitSCM', branches: [[name: "0.6.0"]], userRemoteConfigs: [[url: "https://github.com/milvus-io/milvus-helm.git", name: 'origin', refspec: "+refs/heads/0.6.0:refs/remotes/origin/0.6.0"]]])
     dir ("milvus") {
-    	if ("${env.BINRARY_VERSION}" == "gpu") {
-        	sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f gpu_values.yaml -f ci/filebeat/values.yaml --namespace milvus ."
-    	} else {
-    		sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f ci/filebeat/values.yaml --namespace milvus ."
-    	}
+        sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f ci/db_backend/sqlite_${env.BINRARY_VERSION}_values.yaml -f ci/filebeat/values.yaml --namespace milvus ."
     }
 }
 
diff --git a/ci/jenkins/step/singleDevNightlyTest.groovy b/ci/jenkins/step/singleDevNightlyTest.groovy
index d357badfd3..e27bc6c0a5 100644
--- a/ci/jenkins/step/singleDevNightlyTest.groovy
+++ b/ci/jenkins/step/singleDevNightlyTest.groovy
@@ -13,11 +13,7 @@ timeout(time: 90, unit: 'MINUTES') {
     }
     dir ("milvus-helm") {
         dir ("milvus") {
-            if ("${env.BINRARY_VERSION}" == "gpu") {
-                sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f gpu_values.yaml -f ci/db_backend/mysql_values.yaml -f ci/filebeat/values.yaml --namespace milvus ."
-            } else {
-                sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f ci/db_backend/mysql_values.yaml -f ci/filebeat/values.yaml --namespace milvus ."
-            }
+            sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f ci/db_backend/mysql_${env.BINRARY_VERSION}_values.yaml -f ci/filebeat/values.yaml --namespace milvus ."
         }
     }
     dir ("tests/milvus_python_test") {
diff --git a/ci/jenkins/step/singleDevTest.groovy b/ci/jenkins/step/singleDevTest.groovy
index c1de5907b0..08812ae01f 100644
--- a/ci/jenkins/step/singleDevTest.groovy
+++ b/ci/jenkins/step/singleDevTest.groovy
@@ -14,11 +14,7 @@ timeout(time: 60, unit: 'MINUTES') {
     // }
     // dir ("milvus-helm") {
     //     dir ("milvus") {
-    //         if ("${env.BINRARY_VERSION}" == "gpu") {
-    //             sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f gpu_values.yaml -f ci/db_backend/mysql_values.yaml -f ci/filebeat/values.yaml --namespace milvus ."
-    //         } else {
-    //             sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f ci/db_backend/mysql_values.yaml -f ci/filebeat/values.yaml --namespace milvus ."
-    //         }
+    //         sh "helm install --wait --timeout 300 --set engine.image.tag=${DOCKER_VERSION} --set expose.type=clusterIP --name ${env.PIPELINE_NAME}-${env.BUILD_NUMBER}-single-${env.BINRARY_VERSION} -f ci/db_backend/mysql_${env.BINRARY_VERSION}_values.yaml -f ci/filebeat/values.yaml --namespace milvus ."
     //     }
     // }
     // dir ("tests/milvus_python_test") {
diff --git a/core/src/scheduler/SchedInst.cpp b/core/src/scheduler/SchedInst.cpp
index 97c51407c5..867052ef5d 100644
--- a/core/src/scheduler/SchedInst.cpp
+++ b/core/src/scheduler/SchedInst.cpp
@@ -91,6 +91,7 @@ load_simple_config() {
 void
 StartSchedulerService() {
     load_simple_config();
+    OptimizerInst::GetInstance()->Init();
     ResMgrInst::GetInstance()->Start();
     SchedInst::GetInstance()->Start();
     JobMgrInst::GetInstance()->Start();
diff --git a/core/src/scheduler/SchedInst.h b/core/src/scheduler/SchedInst.h
index 102dc17b1d..48eaffc0a5 100644
--- a/core/src/scheduler/SchedInst.h
+++ b/core/src/scheduler/SchedInst.h
@@ -23,6 +23,7 @@
 #include "Scheduler.h"
 #include "Utils.h"
 #include "optimizer/BuildIndexPass.h"
+#include "optimizer/FallbackPass.h"
 #include "optimizer/HybridPass.h"
 #include "optimizer/LargeSQ8HPass.h"
 #include "optimizer/OnlyCPUPass.h"
@@ -103,12 +104,14 @@ class OptimizerInst {
                 pass_list.push_back(std::make_shared<HybridPass>());
 #ifdef MILVUS_CPU_VERSION
                 pass_list.push_back(std::make_shared<OnlyCPUPass>());
+<<<<<<< HEAD
 #else
                 server::Config& config = server::Config::GetInstance();
                 std::vector<int32_t> build_resources;
                 config.GetGpuResourceConfigBuildIndexResources(build_resources);
                 pass_list.push_back(std::make_shared<BuildIndexPass>(build_resources));
 #endif
+//                pass_list.push_back(std::make_shared<FallbackPass>());
                 instance = std::make_shared<Optimizer>(pass_list);
             }
         }
diff --git a/core/src/scheduler/optimizer/BuildIndexPass.cpp b/core/src/scheduler/optimizer/BuildIndexPass.cpp
index dea4d9d5c7..4e7d5222e2 100644
--- a/core/src/scheduler/optimizer/BuildIndexPass.cpp
+++ b/core/src/scheduler/optimizer/BuildIndexPass.cpp
@@ -26,6 +26,10 @@ namespace scheduler {
 BuildIndexPass::BuildIndexPass(std::vector<int32_t>& build_gpu_ids) : build_gpu_ids_(build_gpu_ids) {
 }
 
+void
+BuildIndexPass::Init() {
+}
+
 bool
 BuildIndexPass::Run(const TaskPtr& task) {
     if (task->Type() != TaskType::BuildIndexTask)
diff --git a/core/src/scheduler/optimizer/BuildIndexPass.h b/core/src/scheduler/optimizer/BuildIndexPass.h
index 5b04ec1dce..a3eb426527 100644
--- a/core/src/scheduler/optimizer/BuildIndexPass.h
+++ b/core/src/scheduler/optimizer/BuildIndexPass.h
@@ -37,6 +37,9 @@ class BuildIndexPass : public Pass {
     explicit BuildIndexPass(std::vector<int32_t>& build_gpu_id);
 
  public:
+    void
+    Init() override;
+
     bool
     Run(const TaskPtr& task) override;
 
diff --git a/core/src/scheduler/optimizer/FallbackPass.cpp b/core/src/scheduler/optimizer/FallbackPass.cpp
new file mode 100644
index 0000000000..2e275ede4b
--- /dev/null
+++ b/core/src/scheduler/optimizer/FallbackPass.cpp
@@ -0,0 +1,43 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+#include "scheduler/optimizer/FallbackPass.h"
+#include "scheduler/SchedInst.h"
+#include "scheduler/tasklabel/SpecResLabel.h"
+
+namespace milvus {
+namespace scheduler {
+
+void
+FallbackPass::Init() {
+}
+
+bool
+FallbackPass::Run(const TaskPtr& task) {
+    auto task_type = task->Type();
+    if (task_type != TaskType::SearchTask && task_type != TaskType::BuildIndexTask) {
+        return false;
+    }
+    // NEVER be empty
+    auto cpu = ResMgrInst::GetInstance()->GetCpuResources()[0];
+    auto label = std::make_shared<SpecResLabel>(cpu);
+    task->label() = label;
+    return true;
+}
+
+}  // namespace scheduler
+}  // namespace milvus
diff --git a/core/src/scheduler/optimizer/FallbackPass.h b/core/src/scheduler/optimizer/FallbackPass.h
new file mode 100644
index 0000000000..728740d53a
--- /dev/null
+++ b/core/src/scheduler/optimizer/FallbackPass.h
@@ -0,0 +1,40 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+#pragma once
+
+#include <bits/stdc++.h>
+#include <memory>
+
+#include "Pass.h"
+
+namespace milvus {
+namespace scheduler {
+
+class FallbackPass : public Pass {
+ public:
+    FallbackPass() = default;
+
+ public:
+    void
+    Init() override;
+
+    bool
+    Run(const TaskPtr& task) override;
+};
+
+}  // namespace scheduler
+}  // namespace milvus
diff --git a/core/src/scheduler/optimizer/HybridPass.cpp b/core/src/scheduler/optimizer/HybridPass.cpp
index d63fc2e819..8bf0d8990d 100644
--- a/core/src/scheduler/optimizer/HybridPass.cpp
+++ b/core/src/scheduler/optimizer/HybridPass.cpp
@@ -23,6 +23,10 @@
 namespace milvus {
 namespace scheduler {
 
+void
+HybridPass::Init() {
+}
+
 bool
 HybridPass::Run(const TaskPtr& task) {
     // TODO: future, Index::IVFSQ8H, if nq < threshold set cpu, else set gpu
diff --git a/core/src/scheduler/optimizer/HybridPass.h b/core/src/scheduler/optimizer/HybridPass.h
index 0d02a8bda9..f84a0884f2 100644
--- a/core/src/scheduler/optimizer/HybridPass.h
+++ b/core/src/scheduler/optimizer/HybridPass.h
@@ -37,6 +37,9 @@ class HybridPass : public Pass {
     HybridPass() = default;
 
  public:
+    void
+    Init() override;
+
     bool
     Run(const TaskPtr& task) override;
 };
diff --git a/core/src/scheduler/optimizer/LargeSQ8HPass.cpp b/core/src/scheduler/optimizer/LargeSQ8HPass.cpp
index 316e0f9aa4..dd58feb512 100644
--- a/core/src/scheduler/optimizer/LargeSQ8HPass.cpp
+++ b/core/src/scheduler/optimizer/LargeSQ8HPass.cpp
@@ -27,7 +27,8 @@
 namespace milvus {
 namespace scheduler {
 
-LargeSQ8HPass::LargeSQ8HPass() {
+void
+LargeSQ8HPass::Init() {
     server::Config& config = server::Config::GetInstance();
     Status s = config.GetEngineConfigGpuSearchThreshold(threshold_);
     if (!s.ok()) {
diff --git a/core/src/scheduler/optimizer/LargeSQ8HPass.h b/core/src/scheduler/optimizer/LargeSQ8HPass.h
index bec9003250..c69fb12c64 100644
--- a/core/src/scheduler/optimizer/LargeSQ8HPass.h
+++ b/core/src/scheduler/optimizer/LargeSQ8HPass.h
@@ -35,9 +35,12 @@ namespace scheduler {
 
 class LargeSQ8HPass : public Pass {
  public:
-    LargeSQ8HPass();
+    LargeSQ8HPass() = default;
 
  public:
+    void
+    Init() override;
+
     bool
     Run(const TaskPtr& task) override;
 
diff --git a/core/src/scheduler/optimizer/OnlyCPUPass.cpp b/core/src/scheduler/optimizer/OnlyCPUPass.cpp
index fee79ea277..8cd40092fb 100644
--- a/core/src/scheduler/optimizer/OnlyCPUPass.cpp
+++ b/core/src/scheduler/optimizer/OnlyCPUPass.cpp
@@ -24,6 +24,10 @@
 namespace milvus {
 namespace scheduler {
 
+void
+OnlyCPUPass::Init() {
+}
+
 bool
 OnlyCPUPass::Run(const TaskPtr& task) {
     if (task->Type() != TaskType::SearchTask)
diff --git a/core/src/scheduler/optimizer/OnlyCPUPass.h b/core/src/scheduler/optimizer/OnlyCPUPass.h
index 76b42e3766..253775f77e 100644
--- a/core/src/scheduler/optimizer/OnlyCPUPass.h
+++ b/core/src/scheduler/optimizer/OnlyCPUPass.h
@@ -37,6 +37,9 @@ class OnlyCPUPass : public Pass {
     OnlyCPUPass() = default;
 
  public:
+    void
+    Init() override;
+
     bool
     Run(const TaskPtr& task) override;
 };
diff --git a/core/src/scheduler/optimizer/Optimizer.cpp b/core/src/scheduler/optimizer/Optimizer.cpp
index 46f24ea712..c5fa311a27 100644
--- a/core/src/scheduler/optimizer/Optimizer.cpp
+++ b/core/src/scheduler/optimizer/Optimizer.cpp
@@ -20,12 +20,12 @@
 namespace milvus {
 namespace scheduler {
 
-// void
-// Optimizer::Init() {
-//    for (auto& pass : pass_list_) {
-//        pass->Init();
-//    }
-// }
+void
+Optimizer::Init() {
+    for (auto& pass : pass_list_) {
+        pass->Init();
+    }
+}
 
 bool
 Optimizer::Run(const TaskPtr& task) {
diff --git a/core/src/scheduler/optimizer/Optimizer.h b/core/src/scheduler/optimizer/Optimizer.h
index bfabbf7de3..68b519e115 100644
--- a/core/src/scheduler/optimizer/Optimizer.h
+++ b/core/src/scheduler/optimizer/Optimizer.h
@@ -38,8 +38,8 @@ class Optimizer {
     explicit Optimizer(std::vector<PassPtr> pass_list) : pass_list_(std::move(pass_list)) {
     }
 
-    //    void
-    //    Init();
+    void
+    Init();
 
     bool
     Run(const TaskPtr& task);
diff --git a/core/src/scheduler/optimizer/Pass.h b/core/src/scheduler/optimizer/Pass.h
index 016b05e457..36a36a1df5 100644
--- a/core/src/scheduler/optimizer/Pass.h
+++ b/core/src/scheduler/optimizer/Pass.h
@@ -34,9 +34,8 @@ namespace scheduler {
 
 class Pass {
  public:
-    //    virtual void
-    //    Init() {
-    //    }
+    virtual void
+    Init() = 0;
 
     virtual bool
     Run(const TaskPtr& task) = 0;
diff --git a/docs/test_report/milvus_ivfsq8_test_report_detailed_version.md b/docs/test_report/milvus_ivfsq8_test_report_detailed_version.md
index 4d6840430e..7bea764df0 100644
--- a/docs/test_report/milvus_ivfsq8_test_report_detailed_version.md
+++ b/docs/test_report/milvus_ivfsq8_test_report_detailed_version.md
@@ -28,13 +28,13 @@ Memory: 503GB
 
 Docker version: 18.09
 
-Nvidia Driver version: 430.34
+NVIDIA Driver version: 430.34
 
 Milvus version: 0.5.3
 
 SDK interface: Python 3.6.8
 
-Pymilvus version: 0.2.5
+pymilvus version: 0.2.5
 
 
 
@@ -66,7 +66,7 @@ For details on this dataset, you can check : http://corpus-texmex.irisa.fr/ .
 
   > Note: In the query test of recall, we will test the following parameters with different values:
   >
-  > nq - grouped by: [1, 5, 10,  200, 400, 600, 800, 1000], 
+  > nq - grouped by: [10,  200, 400, 600, 800, 1000], 
   >
   > topk - grouped by: [1, 10, 100]
 
@@ -93,7 +93,7 @@ Milvus configuration
 - gpu_cache_capacity: 6
 - use_blas_threshold: 1100
 
-You can check the definition of Milvus configuration on https://milvus.io/docs/en/reference/milvus_config/.
+The definitions of Milvus configuration are on https://milvus.io/docs/en/reference/milvus_config/.
 
 Test method
 
@@ -177,8 +177,6 @@ search_resources: gpu0, gpu1
 
 | nq/topk | topk=1 | topk=10 | topk=100 |
 | :-----: | :----: | :-----: | :------: |
-|  nq=1   | 1.000  |  0.800  |  0.790   |
-|  nq=5   | 0.800  |  0.820  |  0.908   |
 |  nq=10  | 0.900  |  0.910  |  0.939   |
 | nq=200  | 0.955  |  0.941  |  0.929   |
 | nq=400  | 0.958  |  0.944  |  0.932   |
@@ -194,8 +192,6 @@ search_resources: cpu, gpu0
 
 | nq/topk | topk=1 | topk=10 | topk=100 |
 | :-----: | :----: | :-----: | :------: |
-|  nq=1   | 1.000  |  0.800  |  0.790   |
-|  nq=5   | 0.800  |  0.820  |  0.908   |
 |  nq=10  | 0.900  |  0.910  |  0.939   |
 | nq=200  | 0.955  |  0.941  |  0.929   |
 | nq=400  | 0.958  |  0.944  |  0.932   |
diff --git a/docs/test_report/milvus_ivfsq8_test_report_detailed_version_cn.md b/docs/test_report/milvus_ivfsq8_test_report_detailed_version_cn.md
index 4b5e18f291..a6e5e75ea4 100644
--- a/docs/test_report/milvus_ivfsq8_test_report_detailed_version_cn.md
+++ b/docs/test_report/milvus_ivfsq8_test_report_detailed_version_cn.md
@@ -2,7 +2,7 @@
 
 ## 概述
 
-本文描述了ivfsq8索引在milvus单机部署方式下的测试报告。
+本文描述了ivfsq8索引在milvus单机部署方式下的测试结果。
 
 
 
@@ -28,13 +28,13 @@ GPU1: GeForce GTX 1080
 
 Docker版本: 18.09
 
-Nvidia Driver版本: 430.34
+NVIDIA Driver版本: 430.34
 
 Milvus版本: 0.5.3
 
 SDK接口: Python 3.6.8
 
-Pymilvus版本: 0.2.5
+pymilvus版本: 0.2.5
 
 
 
@@ -66,7 +66,7 @@ Pymilvus版本: 0.2.5
 
   > 备注：在向量准确性测试中，我们会测试下面参数不同的取值来观察结果：
   >
-  > 被查询向量的数量nq将按照 [1, 5, 10,  200, 400, 600, 800, 1000]的数量分组，
+  > 被查询向量的数量nq将按照 [10,  200, 400, 600, 800, 1000]的数量分组，
   >
   > 单条查询中最相似的K个结果topk将按照[1, 10, 100]的数量分组。
 
@@ -93,7 +93,7 @@ Milvus设置：
 - gpu_cache_capacity: 6
 - use_blas_threshold: 1100
 
-你可以在 https://milvus.io/docs/en/reference/milvus_config/上查询Milvus设置的详细定义。
+Milvus设置的详细定义可以参考 https://milvus.io/docs/en/reference/milvus_config/ 。
 
 测试方法
 
@@ -177,8 +177,6 @@ search_resources: gpu0, gpu1
 
 | nq/topk | topk=1 | topk=10 | topk=100 |
 | :-----: | :----: | :-----: | :------: |
-|  nq=1   | 1.000  |  0.800  |  0.790   |
-|  nq=5   | 0.800  |  0.820  |  0.908   |
 |  nq=10  | 0.900  |  0.910  |  0.939   |
 | nq=200  | 0.955  |  0.941  |  0.929   |
 | nq=400  | 0.958  |  0.944  |  0.932   |
@@ -194,8 +192,6 @@ search_resources: cpu, gpu0
 
 | nq/topk | topk=1 | topk=10 | topk=100 |
 | :-----: | :----: | :-----: | :------: |
-|  nq=1   | 1.000  |  0.800  |  0.790   |
-|  nq=5   | 0.800  |  0.820  |  0.908   |
 |  nq=10  | 0.900  |  0.910  |  0.939   |
 | nq=200  | 0.955  |  0.941  |  0.929   |
 | nq=400  | 0.958  |  0.944  |  0.932   |
@@ -207,5 +203,5 @@ search_resources: cpu, gpu0
 
 **总结**
 
-​		随着nq的增大，召回率逐渐稳定至93%以上。
+随着nq的增大，召回率逐渐稳定至93%以上。
 
diff --git a/install.md b/install.md
index 6711b41f76..f53586af36 100644
--- a/install.md
+++ b/install.md
@@ -3,6 +3,9 @@
 ## Software requirements
 
 - Ubuntu 18.04 or higher
+
+  If your operating system is not Ubuntu 18.04 or higher, we recommend you to pull a [docker image of Ubuntu 18.04](https://docs.docker.com/install/linux/docker-ce/ubuntu/) as your compilation environment.
+  
 - CMake 3.12 or higher
 
 ##### For GPU version, you will also need: