diff --git a/source/libs/index/src/index_cache.c b/source/libs/index/src/index_cache.c
index bce9e5fb87..0e46445a00 100644
--- a/source/libs/index/src/index_cache.c
+++ b/source/libs/index/src/index_cache.c
@@ -181,9 +181,9 @@ static void indexCacheMakeRoomForWrite(IndexCache* cache) {
       break;
     } else if (cache->imm != NULL) {
       // TODO: wake up by condition variable
-      // pthread_mutex_unlock(&cache->mtx);
+      pthread_mutex_unlock(&cache->mtx);
       taosMsleep(50);
-      // pthread_mutex_lock(&cache->mtx);
+      pthread_mutex_lock(&cache->mtx);
     } else {
       indexCacheRef(cache);
       cache->imm = cache->mem;
diff --git a/source/libs/index/test/indexTests.cc b/source/libs/index/test/indexTests.cc
index cffb09ee4d..080becccf1 100644
--- a/source/libs/index/test/indexTests.cc
+++ b/source/libs/index/test/indexTests.cc
@@ -15,6 +15,7 @@
 #include <gtest/gtest.h>
 #include <iostream>
 #include <string>
+#include <thread>
 #include "index.h"
 #include "indexInt.h"
 #include "index_cache.h"
@@ -25,6 +26,9 @@
 #include "tskiplist.h"
 #include "tutil.h"
 using namespace std;
+
+#define NUM_OF_THREAD 10
+
 class DebugInfo {
  public:
   DebugInfo(const char* str) : info(str) {
@@ -41,6 +45,7 @@ class DebugInfo {
  private:
   std::string info;
 };
+
 class FstWriter {
  public:
   FstWriter() {
@@ -637,6 +642,23 @@ class IndexObj {
     indexMultiTermDestroy(terms);
     return numOfTable;
   }
+  int WriteMultiMillonData(const std::string& colName, const std::string& colVal = "Hello world",
+                           size_t numOfTable = 100 * 10000) {
+    std::string tColVal = colVal;
+    for (int i = 0; i < numOfTable; i++) {
+      tColVal[tColVal.size() - 1] = 'a' + i % 26;
+      SIndexTerm*      term = indexTermCreate(0, ADD_VALUE, TSDB_DATA_TYPE_BINARY, colName.c_str(), colName.size(),
+                                         colVal.c_str(), colVal.size());
+      SIndexMultiTerm* terms = indexMultiTermCreate();
+      indexMultiTermAdd(terms, term);
+      for (size_t i = 0; i < 10; i++) {
+        int ret = Put(terms, i);
+        assert(ret == 0);
+      }
+      indexMultiTermDestroy(terms);
+    }
+    return numOfTable;
+  }
 
   int Put(SIndexMultiTerm* fvs, uint64_t uid) {
     numOfWrite += taosArrayGetSize(fvs);
@@ -659,6 +681,14 @@ class IndexObj {
     return taosArrayGetSize(result);
     // assert(taosArrayGetSize(result) == targetSize);
   }
+  void PutOne(const std::string& colName, const std::string& colVal) {
+    SIndexTerm*      term = indexTermCreate(0, ADD_VALUE, TSDB_DATA_TYPE_BINARY, colName.c_str(), colName.size(),
+                                       colVal.c_str(), colVal.size());
+    SIndexMultiTerm* terms = indexMultiTermCreate();
+    indexMultiTermAdd(terms, term);
+    Put(terms, 10);
+    indexMultiTermDestroy(terms);
+  }
   void Debug() {
     std::cout << "numOfWrite:" << numOfWrite << std::endl;
     std::cout << "numOfRead:" << numOfRead << std::endl;
@@ -758,15 +788,38 @@ TEST_F(IndexEnv2, testIndexOpen) {
 
 TEST_F(IndexEnv2, testIndex_TrigeFlush) {
   std::string path = "/tmp/test";
-  if (index->Init(path) != 0) {}
+  if (index->Init(path) != 0) {
+    // r
+    std::cout << "failed to init" << std::endl;
+  }
   int numOfTable = 100 * 10000;
   index->WriteMillonData("tag1", "Hello", numOfTable);
   int target = index->SearchOne("tag1", "Hello");
   assert(numOfTable == target);
 }
+
+static void write_and_search(IndexObj* idx) {
+  std::string colName("tag1"), colVal("Hello");
+
+  int target = idx->SearchOne("tag1", "Hello");
+  idx->PutOne(colName, colVal);
+}
 TEST_F(IndexEnv2, testIndex_serarch_cache_and_tfile) {
-  std::string path = "/tmp";
-  if (index->Init(path) != 0) {}
+  std::string path = "/tmp/cache_and_tfile";
+  if (index->Init(path) != 0) {
+    // opt
+  }
+  index->WriteMultiMillonData("tag1", "Hello", 200000);
+  std::thread threads[NUM_OF_THREAD];
+
+  for (int i = 0; i < NUM_OF_THREAD; i++) {
+    //
+    threads[i] = std::thread(write_and_search, index);
+  }
+  for (int i = 0; i < NUM_OF_THREAD; i++) {
+    // TOD
+    threads[i].join();
+  }
 }
 TEST_F(IndexEnv2, testIndex_multi_thread_write) {
   std::string path = "/tmp";