diff --git a/source/libs/index/src/index.c b/source/libs/index/src/index.c
index 57e965a753c08ca323a364d2ac016209ddf4045d..75dc05fc5b8cfdf254eebf9383723f82a3507bed 100644
--- a/source/libs/index/src/index.c
+++ b/source/libs/index/src/index.c
@@ -16,6 +16,7 @@
 #include "index.h"
 #include "indexInt.h"
 #include "index_cache.h"
+#include "index_comm.h"
 #include "index_tfile.h"
 #include "index_util.h"
 #include "tdef.h"
@@ -30,8 +31,6 @@
 
 void* indexQhandle = NULL;
 
-static char JSON_COLUMN[] = "JSON";
-
 #define INDEX_MERGE_ADD_DEL(src, dst, tgt)            \
   {                                                   \
     bool f = false;                                   \
@@ -64,13 +63,11 @@ typedef struct SIdxColInfo {
   int cVersion;
 } SIdxColInfo;
 
-typedef struct SIdxMergeHelper {
-  char*   colVal;
+typedef struct SIdxTempResult {
   SArray* total;
   SArray* added;
   SArray* deled;
-  bool    reset;
-} SIdxMergeHelper;
+} SIdxTempResult;
 
 static pthread_once_t isInit = PTHREAD_ONCE_INIT;
 // static void           indexInit();
@@ -82,8 +79,7 @@ static int  indexMergeFinalResults(SArray* interResults, EIndexOperatorType oTyp
 static int indexGenTFile(SIndex* index, IndexCache* cache, SArray* batch);
 
 // merge cache and tfile by opera type
-static void indexMergeCacheAndTFile(SArray* result, IterateValue* icache, IterateValue* iTfv, SIdxMergeHelper* helper);
-static void indexMergeSameKey(SArray* result, TFileValue* tv, SIdxMergeHelper* helper);
+static void indexMergeCacheAndTFile(SArray* result, IterateValue* icache, IterateValue* iTfv, SIdxTempResult* helper);
 
 // static int32_t indexSerialTermKey(SIndexTerm* itm, char* buf);
 // int32_t        indexSerialKey(ICacheKey* key, char* buf);
@@ -399,7 +395,6 @@ static void indexInterResultsDestroy(SArray* results) {
 
 static int indexMergeFinalResults(SArray* interResults, EIndexOperatorType oType, SArray* fResults) {
   // refactor, merge interResults into fResults by oType
-
   for (int i = 0; i < taosArrayGetSize(interResults); i--) {
     SArray* t = taosArrayGetP(interResults, i);
     taosArraySort(t, uidCompare);
@@ -418,98 +413,82 @@ static int indexMergeFinalResults(SArray* interResults, EIndexOperatorType oType
   return 0;
 }
 
-SIdxMergeHelper* sIdxMergeHelperCreate() {
-  SIdxMergeHelper* hp = calloc(1, sizeof(SIdxMergeHelper));
-  hp->total = taosArrayInit(4, sizeof(uint64_t));
-  hp->added = taosArrayInit(4, sizeof(uint64_t));
-  hp->deled = taosArrayInit(4, sizeof(uint64_t));
-  hp->reset = false;
-  return hp;
+SIdxTempResult* sIdxTempResultCreate() {
+  SIdxTempResult* tr = calloc(1, sizeof(SIdxTempResult));
+  tr->total = taosArrayInit(4, sizeof(uint64_t));
+  tr->added = taosArrayInit(4, sizeof(uint64_t));
+  tr->deled = taosArrayInit(4, sizeof(uint64_t));
+  return tr;
 }
-void sIdxMergeHelperClear(SIdxMergeHelper* hp) {
-  if (hp == NULL) {
+void sIdxTempResultClear(SIdxTempResult* tr) {
+  if (tr == NULL) {
     return;
   }
-  hp->reset = false;
-  taosArrayClear(hp->total);
-  taosArrayClear(hp->added);
-  taosArrayClear(hp->deled);
+  taosArrayClear(tr->total);
+  taosArrayClear(tr->added);
+  taosArrayClear(tr->deled);
 }
-void sIdxMergeHelperDestroy(SIdxMergeHelper* hp) {
-  if (hp == NULL) {
+void sIdxTempResultDestroy(SIdxTempResult* tr) {
+  if (tr == NULL) {
     return;
   }
-  taosArrayDestroy(hp->total);
-  taosArrayDestroy(hp->added);
-  taosArrayDestroy(hp->deled);
+  taosArrayDestroy(tr->total);
+  taosArrayDestroy(tr->added);
+  taosArrayDestroy(tr->deled);
 }
-static void indexMergeSameKey(SArray* result, TFileValue* tv, SIdxMergeHelper* helper) {
-  int32_t sz = result ? taosArrayGetSize(result) : 0;
-  if (sz > 0) {
-    // TODO(yihao): remove duplicate tableid
-    TFileValue* lv = taosArrayGetP(result, sz - 1);
-    // indexError("merge colVal: %s", lv->colVal);
-    if (strcmp(lv->colVal, tv->colVal) == 0) {
-      taosArrayAddAll(lv->tableId, tv->tableId);
-      tfileValueDestroy(tv);
-    } else {
-      taosArrayPush(result, &tv);
-    }
-  } else {
-    taosArrayPush(result, &tv);
-  }
-}
-static void sIdxMergeResult(SArray* result, SIdxMergeHelper* mh) {
-  taosArraySort(mh->total, uidCompare);
-  taosArraySort(mh->added, uidCompare);
-  taosArraySort(mh->deled, uidCompare);
+static void sIdxTempResultMergeTo(SArray* result, SIdxTempResult* tr) {
+  taosArraySort(tr->total, uidCompare);
+  taosArraySort(tr->added, uidCompare);
+  taosArraySort(tr->deled, uidCompare);
 
   SArray* arrs = taosArrayInit(2, sizeof(void*));
-  taosArrayPush(arrs, &mh->total);
-  taosArrayPush(arrs, &mh->added);
+  taosArrayPush(arrs, &tr->total);
+  taosArrayPush(arrs, &tr->added);
 
   iUnion(arrs, result);
   taosArrayDestroy(arrs);
 
-  iExcept(result, mh->deled);
+  iExcept(result, tr->deled);
 }
-static void indexMayMergeToFinalResult(SArray* result, TFileValue* tfv, SIdxMergeHelper* help) {
+static void indexMayMergeTempToFinalResult(SArray* result, TFileValue* tfv, SIdxTempResult* tr) {
   int32_t sz = taosArrayGetSize(result);
   if (sz > 0) {
     TFileValue* lv = taosArrayGetP(result, sz - 1);
     if (tfv != NULL && strcmp(lv->colVal, tfv->colVal) != 0) {
-      sIdxMergeResult(lv->tableId, help);
-      sIdxMergeHelperClear(help);
+      sIdxTempResultMergeTo(lv->tableId, tr);
+      sIdxTempResultClear(tr);
 
       taosArrayPush(result, &tfv);
     } else if (tfv == NULL) {
-      sIdxMergeResult(lv->tableId, help);
+      // handle last iterator
+      sIdxTempResultMergeTo(lv->tableId, tr);
     } else {
+      // temp result saved in help
       tfileValueDestroy(tfv);
     }
   } else {
     taosArrayPush(result, &tfv);
   }
 }
-static void indexMergeCacheAndTFile(SArray* result, IterateValue* cv, IterateValue* tv, SIdxMergeHelper* mh) {
+static void indexMergeCacheAndTFile(SArray* result, IterateValue* cv, IterateValue* tv, SIdxTempResult* tr) {
   char*       colVal = (cv != NULL) ? cv->colVal : tv->colVal;
   TFileValue* tfv = tfileValueCreate(colVal);
 
-  indexMayMergeToFinalResult(result, tfv, mh);
+  indexMayMergeTempToFinalResult(result, tfv, tr);
 
   if (cv != NULL) {
     uint64_t id = *(uint64_t*)taosArrayGet(cv->val, 0);
     if (cv->type == ADD_VALUE) {
-      INDEX_MERGE_ADD_DEL(mh->deled, mh->added, id)
+      INDEX_MERGE_ADD_DEL(tr->deled, tr->added, id)
     } else if (cv->type == DEL_VALUE) {
-      INDEX_MERGE_ADD_DEL(mh->added, mh->deled, id)
+      INDEX_MERGE_ADD_DEL(tr->added, tr->deled, id)
     }
   }
   if (tv != NULL) {
-    taosArrayAddAll(mh->total, tv->val);
+    taosArrayAddAll(tr->total, tv->val);
   }
 }
-static void indexDestroyTempResult(SArray* result) {
+static void indexDestroyFinalResult(SArray* result) {
   int32_t sz = result ? taosArrayGetSize(result) : 0;
   for (size_t i = 0; i < sz; i++) {
     TFileValue* tv = taosArrayGetP(result, i);
@@ -543,7 +522,7 @@ int indexFlushCacheToTFile(SIndex* sIdx, void* cache) {
   bool cn = cacheIter ? cacheIter->next(cacheIter) : false;
   bool tn = tfileIter ? tfileIter->next(tfileIter) : false;
 
-  SIdxMergeHelper* help = sIdxMergeHelperCreate();
+  SIdxTempResult* tr = sIdxTempResultCreate();
   while (cn == true || tn == true) {
     IterateValue* cv = (cn == true) ? cacheIter->getValue(cacheIter) : NULL;
     IterateValue* tv = (tn == true) ? tfileIter->getValue(tfileIter) : NULL;
@@ -557,21 +536,22 @@ int indexFlushCacheToTFile(SIndex* sIdx, void* cache) {
       comp = 1;
     }
     if (comp == 0) {
-      indexMergeCacheAndTFile(result, cv, tv, help);
+      indexMergeCacheAndTFile(result, cv, tv, tr);
       cn = cacheIter->next(cacheIter);
       tn = tfileIter->next(tfileIter);
     } else if (comp < 0) {
-      indexMergeCacheAndTFile(result, cv, NULL, help);
+      indexMergeCacheAndTFile(result, cv, NULL, tr);
       cn = cacheIter->next(cacheIter);
     } else {
-      indexMergeCacheAndTFile(result, NULL, tv, help);
+      indexMergeCacheAndTFile(result, NULL, tv, tr);
       tn = tfileIter->next(tfileIter);
     }
   }
-  indexMayMergeToFinalResult(result, NULL, help);
+  indexMayMergeTempToFinalResult(result, NULL, tr);
+  sIdxTempResultDestroy(tr);
 
   int ret = indexGenTFile(sIdx, pCache, result);
-  indexDestroyTempResult(result);
+  indexDestroyFinalResult(result);
 
   indexCacheDestroyImm(pCache);
 
@@ -581,8 +561,6 @@ int indexFlushCacheToTFile(SIndex* sIdx, void* cache) {
   tfileReaderUnRef(pReader);
   indexCacheUnRef(pCache);
 
-  sIdxMergeHelperDestroy(help);
-
   int64_t cost = taosGetTimestampUs() - st;
   if (ret != 0) {
     indexError("failed to merge, time cost: %" PRId64 "ms", cost / 1000);
diff --git a/source/libs/index/src/index_tfile.c b/source/libs/index/src/index_tfile.c
index 6cfc199afd7fefcef3267806989402bb62da324c..f5f46b061714fa372a2aa52607598cf69214990e 100644
--- a/source/libs/index/src/index_tfile.c
+++ b/source/libs/index/src/index_tfile.c
@@ -102,7 +102,6 @@ void tfileCacheDestroy(TFileCache* tcache) {
   if (tcache == NULL) {
     return;
   }
-
   // free table cache
   TFileReader** reader = taosHashIterate(tcache->tableCache, NULL);
   while (reader) {
diff --git a/source/libs/index/test/jsonUT.cc b/source/libs/index/test/jsonUT.cc
index e5c79d137f43cb7350396211d81c71ec734e3957..df9f8b8439db379e99cfc96b69ea150b7a51577a 100644
--- a/source/libs/index/test/jsonUT.cc
+++ b/source/libs/index/test/jsonUT.cc
@@ -105,6 +105,22 @@ TEST_F(JsonEnv, testWriteMillonData) {
     }
     indexMultiTermDestroy(terms);
   }
+  {
+    std::string colName("voltagefdadfa");
+    std::string colVal("abxxxxxxxxxxxx");
+    for (uint i = 0; i < 1000; i++) {
+      colVal[i % colVal.size()] = '0' + i % 128;
+      SIndexTerm* term = indexTermCreate(1, 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 < 1000; i++) {
+        tIndexJsonPut(index, terms, i);
+      }
+      indexMultiTermDestroy(terms);
+    }
+  }
   {
     std::string colName("voltagefdadfa");
     std::string colVal("abxxxxxxxxxxxx");