diff --git a/source/libs/index/inc/indexCache.h b/source/libs/index/inc/indexCache.h
index d474d87409..96bfb2cd7f 100644
--- a/source/libs/index/inc/indexCache.h
+++ b/source/libs/index/inc/indexCache.h
@@ -63,6 +63,7 @@ typedef struct CacheTerm {
 
 IndexCache* indexCacheCreate(SIndex* idx, uint64_t suid, const char* colName, int8_t type);
 
+void indexCacheForceToMerge(void* cache);
 void indexCacheDestroy(void* cache);
 
 Iterate* indexCacheIteratorCreate(IndexCache* cache);
diff --git a/source/libs/index/src/index.c b/source/libs/index/src/index.c
index 92159dae7a..d1f50f1979 100644
--- a/source/libs/index/src/index.c
+++ b/source/libs/index/src/index.c
@@ -124,15 +124,21 @@ END:
 
 void indexDestroy(void* handle) {
   SIndex* sIdx = handle;
-  void*   iter = taosHashIterate(sIdx->colObj, NULL);
-  while (iter) {
-    IndexCache** pCache = iter;
-    if (*pCache) {
+  // indexAcquireRef(sIdx->refId);
+  if (sIdx->colObj != NULL) {
+    void* iter = taosHashIterate(sIdx->colObj, NULL);
+    while (iter) {
+      IndexCache** pCache = iter;
+      indexCacheForceToMerge((void*)(*pCache));
+      iter = taosHashIterate(sIdx->colObj, iter);
+
       indexCacheUnRef(*pCache);
     }
-    iter = taosHashIterate(sIdx->colObj, iter);
-  }
-  taosHashCleanup(sIdx->colObj);
+    taosHashCleanup(sIdx->colObj);
+    sIdx->colObj = NULL;
+    return;
+  }  // indexReleaseRef(sIdx->refId);
+
   taosThreadMutexDestroy(&sIdx->mtx);
   indexTFileDestroy(sIdx->tindex);
   taosMemoryFree(sIdx->path);
@@ -177,7 +183,6 @@ int indexPut(SIndex* index, SIndexMultiTerm* fVals, uint64_t uid) {
       taosHashPut(index->colObj, buf, sz, &pCache, sizeof(void*));
     }
   }
-  taosThreadMutexUnlock(&index->mtx);
 
   for (int i = 0; i < taosArrayGetSize(fVals); i++) {
     SIndexTerm* p = taosArrayGetP(fVals, i);
@@ -193,6 +198,7 @@ int indexPut(SIndex* index, SIndexMultiTerm* fVals, uint64_t uid) {
       return ret;
     }
   }
+  taosThreadMutexUnlock(&index->mtx);
   return 0;
 }
 int indexSearch(SIndex* index, SIndexMultiTermQuery* multiQuerys, SArray* result) {
@@ -451,6 +457,14 @@ int indexFlushCacheToTFile(SIndex* sIdx, void* cache) {
   }
   // handle flush
   Iterate* cacheIter = indexCacheIteratorCreate(pCache);
+  if (cacheIter == NULL) {
+    indexError("%p immtable is empty, ignore merge opera", pCache);
+    indexCacheDestroyImm(pCache);
+    tfileReaderUnRef(pReader);
+    indexReleaseRef(sIdx->refId);
+    return 0;
+  }
+
   Iterate* tfileIter = tfileIteratorCreate(pReader);
   if (tfileIter == NULL) {
     indexWarn("empty tfile reader iterator");
diff --git a/source/libs/index/src/indexCache.c b/source/libs/index/src/indexCache.c
index 5f7cc10b99..ef01094b5d 100644
--- a/source/libs/index/src/indexCache.c
+++ b/source/libs/index/src/indexCache.c
@@ -429,11 +429,13 @@ void indexCacheDestroy(void* cache) {
 }
 
 Iterate* indexCacheIteratorCreate(IndexCache* cache) {
+  if (cache->imm == NULL) {
+    return NULL;
+  }
   Iterate* iiter = taosMemoryCalloc(1, sizeof(Iterate));
   if (iiter == NULL) {
     return NULL;
   }
-
   taosThreadMutexLock(&cache->mtx);
 
   indexMemRef(cache->imm);
@@ -463,12 +465,9 @@ int indexCacheSchedToMerge(IndexCache* pCache) {
   schedMsg.fp = doMergeWork;
   schedMsg.ahandle = pCache;
   schedMsg.thandle = NULL;
-  // schedMsg.thandle = taosMemoryCalloc(1, sizeof(int64_t));
-  // memcpy((char*)(schedMsg.thandle), (char*)&(pCache->index->refId), sizeof(int64_t));
   schedMsg.msg = NULL;
   indexAcquireRef(pCache->index->refId);
   taosScheduleTask(indexQhandle, &schedMsg);
-
   return 0;
 }
 
@@ -533,6 +532,19 @@ int indexCachePut(void* cache, SIndexTerm* term, uint64_t uid) {
   return 0;
   // encode end
 }
+void indexCacheForceToMerge(void* cache) {
+  IndexCache* pCache = cache;
+  indexCacheRef(pCache);
+  taosThreadMutexLock(&pCache->mtx);
+
+  indexInfo("%p is forced to merge into tfile", pCache);
+  pCache->occupiedMem += MEM_THRESHOLD * 5;
+  indexCacheMakeRoomForWrite(pCache);
+
+  taosThreadMutexUnlock(&pCache->mtx);
+  indexCacheUnRef(pCache);
+  return;
+}
 int indexCacheDel(void* cache, const char* fieldValue, int32_t fvlen, uint64_t uid, int8_t operType) {
   IndexCache* pCache = cache;
   return 0;
diff --git a/source/libs/index/test/indexTests.cc b/source/libs/index/test/indexTests.cc
index 733f1b4ed1..262bbfe55a 100644
--- a/source/libs/index/test/indexTests.cc
+++ b/source/libs/index/test/indexTests.cc
@@ -272,9 +272,26 @@ void validateFst() {
   }
   delete m;
 }
+static std::string logDir = "/tmp/log";
+
+static void initLog() {
+  const char*   defaultLogFileNamePrefix = "taoslog";
+  const int32_t maxLogFileNum = 10;
+
+  tsAsyncLog = 0;
+  sDebugFlag = 143;
+  strcpy(tsLogDir, logDir.c_str());
+  taosRemoveDir(tsLogDir);
+  taosMkDir(tsLogDir);
+
+  if (taosInitLog(defaultLogFileNamePrefix, maxLogFileNum) < 0) {
+    printf("failed to open log file in directory:%s\n", tsLogDir);
+  }
+}
 class IndexEnv : public ::testing::Test {
  protected:
   virtual void SetUp() {
+    initLog();
     taosRemoveDir(path);
     opts = indexOptsCreate();
     int ret = indexOpen(opts, path, &index);
@@ -804,7 +821,7 @@ class IndexObj {
   }
 
   ~IndexObj() {
-    indexCleanUp();
+    // indexCleanUp();
     indexClose(idx);
   }
 
@@ -884,7 +901,7 @@ TEST_F(IndexEnv2, testIndexOpen) {
     SArray* result = (SArray*)taosArrayInit(1, sizeof(uint64_t));
     index->Search(mq, result);
     std::cout << "target size: " << taosArrayGetSize(result) << std::endl;
-    assert(taosArrayGetSize(result) == 400);
+    EXPECT_EQ(400, taosArrayGetSize(result));
     taosArrayDestroy(result);
     indexMultiTermQueryDestroy(mq);
   }