diff --git a/source/libs/index/inc/index_cache.h b/source/libs/index/inc/index_cache.h
new file mode 100644
index 0000000000000000000000000000000000000000..27e095ff31676df7a5623b6468e56fa03f179007
--- /dev/null
+++ b/source/libs/index/inc/index_cache.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef __INDEX_CACHE_H__
+#define __INDEX_CACHE_H__
+
+#include "index.h"
+#include "tlockfree.h"
+// ----------------- row structure in skiplist ---------------------
+
+/* A data row, the format is like below:
+ * |<--totalLen-->|<-- fieldId-->|<-- value len--->|<-- value-->|<--version--->|<-- itermType -->|
+ *
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct IndexCache {
+  T_REF_DECLARE() 
+  int cVersion; // 
+} IndexCache;
+
+
+// 
+IndexCache *indexCacheCreate();
+
+void indexCacheDestroy(IndexCache *cache);
+
+int indexCachePut(IndexCache *cache, int32_t fieldId,  const char *fieldVale,  int32_t fvlen, uint64_t uid, int8_t operaType); 
+
+int indexCacheGet(IndexCache *cache, uint64_t *rst);
+int indexCacheSearch(IndexCache *cache, SIndexMultiTermQuery *query, SArray *result);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+
+#endif
diff --git a/source/libs/index/src/index_cache.c b/source/libs/index/src/index_cache.c
new file mode 100644
index 0000000000000000000000000000000000000000..7c355b0f0a5e712a8ce0143256a9cd76a2fd6632
--- /dev/null
+++ b/source/libs/index/src/index_cache.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
+ *
+ * This program is free software: you can use, redistribute, and/or modify
+ * it under the terms of the GNU Affero General Public License, version 3
+ * or later ("AGPL"), as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "index_cache.h"
+
+static int32_t compareKey(const void *l, const void *r) {
+  char *lp = (char *)l;
+  char *rp = (char *)r;
+
+  // skip total len
+  int32_t ll, rl;  // len    
+  memcpy(&ll, lp, sizeof(int32_t));
+  memcpy(&rl, rp, sizeof(int32_t));
+  lp += sizeof(int32_t); 
+  rp += sizeof(int32_t);
+  
+  // compare field id
+  int32_t lf, rf; // field id
+  memcpy(&lf, lp, sizeof(lf));
+  memcpy(&rf, rp, sizeof(rf));
+  if (lf != rf) {
+    return lf < rf ? -1: 1;
+  }
+  lp += sizeof(lf);
+  rp += sizeof(rf);
+
+  // compare field value 
+  int32_t lfl, rfl;
+  memcpy(&lfl, lp, sizeof(lfl)); 
+  memcpy(&rfl, rp, sizeof(rfl)); 
+  lp += sizeof(lfl);
+  rp += sizeof(rfl);
+  
+  //refator later
+  int32_t i, j;
+  for (i = 0, j = 0; i < lfl && j < rfl; i++, j++) {
+    if (lp[i] == rp[j]) { continue; }
+    else { return lp[i] < rp[j] ? -1 : 1;}
+  }
+  if (i < lfl) { return  1;}
+  else if (j < rfl) { return -1; }
+  lp += lfl;
+  rp += rfl; 
+
+  // compare version
+  int32_t lv, rv;
+  memcpy(&lv, lp, sizeof(lv));
+  memcpy(&rv, rp, sizeof(rv));
+  if (lv != rv) {
+    return lv > rv ? -1 : 1; 
+  }  
+  lp += sizeof(lv);
+  rp += sizeof(rv);
+
+  
+  return 0;  
+  
+} 
+IndexCache *indexCacheCreate() {
+  IndexCache *cache = calloc(1, sizeof(IndexCache));
+  return cache;
+}
+
+void indexCacheDestroy(IndexCache *cache) {
+  free(cache);
+}
+
+int indexCachePut(IndexCache *cache, int32_t fieldId, const char *fieldValue,  int32_t fvlen, uint64_t uid, int8_t operType) {
+  if (cache == NULL) { return -1;} 
+  int32_t version = T_REF_INC(cache);     
+
+  int32_t total = sizeof(int32_t) + sizeof(fieldId) + 4 + fvlen  + sizeof(version) + sizeof(uid) + sizeof(operType); 
+
+  char *buf = calloc(1, total); 
+  char *p   = buf;
+
+  memcpy(buf, &total, sizeof(total)); 
+  total += total;
+
+  memcpy(buf, &fieldId, sizeof(fieldId));   
+  buf += sizeof(fieldId);
+
+  memcpy(buf, &fvlen, sizeof(fvlen));
+  buf += sizeof(fvlen);
+  memcpy(buf, fieldValue, fvlen); 
+  buf += fvlen;
+
+  memcpy(buf, &version, sizeof(version));
+  buf += sizeof(version);
+
+  memcpy(buf, &uid, sizeof(uid));  
+  buf += sizeof(uid);
+
+  memcpy(buf, &operType, sizeof(operType));
+  buf += sizeof(operType); 
+ 
+
+}
+int indexCacheSearch(IndexCache *cache, SIndexMultiTermQuery *query, SArray *result) {
+  
+  return 0;  
+}
+
+
+
+
+