diff --git a/cpp/build.sh b/cpp/build.sh
index f21e2234fa..86af2d42e0 100755
--- a/cpp/build.sh
+++ b/cpp/build.sh
@@ -9,15 +9,12 @@ DB_PATH="/opt/milvus"
 PROFILING="OFF"
 BUILD_FAISS_WITH_MKL="OFF"
 USE_JFROG_CACHE="OFF"
-KNOWHERE_BUILD_DIR="`pwd`/src/core/cmake_build"
-KNOWHERE_OPTIONS="-t ${BUILD_TYPE}"
 
-while getopts "p:d:t:k:uhrcgmj" arg
+while getopts "p:d:t:uhrcgmj" arg
 do
         case $arg in
              t)
                 BUILD_TYPE=$OPTARG # BUILD_TYPE
-                KNOWHERE_OPTIONS="-t ${BUILD_TYPE}"
                 ;;
              u)
                 echo "Build and run unittest cases" ;
@@ -41,15 +38,11 @@ do
              g)
                 PROFILING="ON"
                 ;;
-             k)
-                KNOWHERE_BUILD_DIR=$OPTARG
-                ;;
              m)
                 BUILD_FAISS_WITH_MKL="ON"
                 ;;
              j)
                 USE_JFROG_CACHE="ON"
-                KNOWHERE_OPTIONS="${KNOWHERE_OPTIONS} -j"
                 ;;
              h) # help
                 echo "
@@ -62,7 +55,6 @@ parameter:
 -r: remove previous build directory(default: OFF)
 -c: code coverage(default: OFF)
 -g: profiling(default: OFF)
--k: specify knowhere header/binary path
 -m: build faiss with MKL(default: OFF)
 -j: use jfrog cache build directory
 
@@ -96,7 +88,6 @@ if [[ ${MAKE_CLEAN} == "ON" ]]; then
     -DMILVUS_DB_PATH=${DB_PATH} \
     -DMILVUS_ENABLE_PROFILING=${PROFILING} \
     -DBUILD_FAISS_WITH_MKL=${BUILD_FAISS_WITH_MKL} \
-    -DKNOWHERE_BUILD_DIR=${KNOWHERE_BUILD_DIR} \
     -DUSE_JFROG_CACHE=${USE_JFROG_CACHE} \
     ../"
     echo ${CMAKE_CMD}
diff --git a/cpp/conf/server_config.template b/cpp/conf/server_config.template
index f1615b360c..804025b3b5 100644
--- a/cpp/conf/server_config.template
+++ b/cpp/conf/server_config.template
@@ -31,8 +31,6 @@ cache_config:
   cpu_cache_capacity: 16            # how many memory are used as cache, unit: GB, range: 0 ~ less than total memory
   cpu_cache_free_percent: 0.85      # old data will be erased from cache when cache is full, this value specify how much memory should be kept, range: greater than zero ~ 1.0
   insert_cache_immediately: false   # insert data will be load into cache immediately for hot query
-  gpu_cache_capacity: 5             # how many memory are used as cache in gpu, unit: GB, RANGE: 0 ~ less than total memory
-  gpu_cache_free_percent: 0.85      # old data will be erased from cache when cache is full, this value specify how much memory should be kept, range: greater than zero ~ 1.0
 
 engine_config:
   use_blas_threshold: 20
diff --git a/cpp/coverage.sh b/cpp/coverage.sh
index 701416921f..156da43a4b 100755
--- a/cpp/coverage.sh
+++ b/cpp/coverage.sh
@@ -13,6 +13,10 @@ DIR_LCOV_OUTPUT="lcov_out"
 
 DIR_GCNO="cmake_build"
 DIR_UNITTEST="milvus/unittest"
+
+# delete old code coverage info files
+rm -rf lcov_out
+rm -f FILE_INFO_BASE FILE_INFO_MILVUS FILE_INFO_OUTPUT FILE_INFO_OUTPUT_NEW
  
 MYSQL_USER_NAME=root
 MYSQL_PASSWORD=Fantast1c
@@ -84,7 +88,7 @@ done
 
 mysql_exc "DROP DATABASE IF EXISTS ${MYSQL_DB_NAME};"
 
-# gen test converage
+# gen code coverage
 ${LCOV_CMD} -d ${DIR_GCNO} -o "${FILE_INFO_MILVUS}" -c
 # merge coverage
 ${LCOV_CMD} -a ${FILE_INFO_BASE} -a ${FILE_INFO_MILVUS} -o "${FILE_INFO_OUTPUT}"
diff --git a/cpp/src/cache/GpuCacheMgr.cpp b/cpp/src/cache/GpuCacheMgr.cpp
index 0b6a6132d8..5c1afa3f5c 100644
--- a/cpp/src/cache/GpuCacheMgr.cpp
+++ b/cpp/src/cache/GpuCacheMgr.cpp
@@ -23,7 +23,7 @@ namespace {
 GpuCacheMgr::GpuCacheMgr() {
     server::ConfigNode& config = server::ServerConfig::GetInstance().GetConfig(server::CONFIG_CACHE);
 
-    int64_t cap = config.GetInt64Value(server::CONFIG_GPU_CACHE_CAPACITY, 2);
+    int64_t cap = config.GetInt64Value(server::CONFIG_GPU_CACHE_CAPACITY, 0);
     cap *= G_BYTE;
     cache_ = std::make_shared<Cache>(cap, 1UL<<32);
 
diff --git a/cpp/src/server/ServerConfig.cpp b/cpp/src/server/ServerConfig.cpp
index da898d2239..9934cdc5ad 100644
--- a/cpp/src/server/ServerConfig.cpp
+++ b/cpp/src/server/ServerConfig.cpp
@@ -305,7 +305,7 @@ ServerConfig::CheckCacheConfig() {
         okay = false;
     }
 
-    std::string gpu_cache_capacity_str = cache_config.GetValue(CONFIG_GPU_CACHE_CAPACITY, "5");
+    std::string gpu_cache_capacity_str = cache_config.GetValue(CONFIG_GPU_CACHE_CAPACITY, "0");
     if (ValidationUtil::ValidateStringIsNumber(gpu_cache_capacity_str) != SERVER_SUCCESS) {
         std::cerr << "ERROR: gpu_cache_capacity " << gpu_cache_capacity_str << " is not a number" << std::endl;
         okay = false;