diff --git a/source/libs/index/inc/indexInt.h b/source/libs/index/inc/indexInt.h
index a258cb834d..22bb9d1d0f 100644
--- a/source/libs/index/inc/indexInt.h
+++ b/source/libs/index/inc/indexInt.h
@@ -76,7 +76,7 @@ struct SIndexMultiTermQuery {
 
 // field and key;
 typedef struct SIndexTerm {
-  int64_t           suid; 
+  int64_t            suid; 
   SIndexOperOnColumn operType; // oper type, add/del/update
   uint8_t            colType;  // term data type, str/interger/json
   char    *colName;
diff --git a/source/libs/index/inc/index_fst_counting_writer.h b/source/libs/index/inc/index_fst_counting_writer.h
index ea090389bb..ac9a59fa04 100644
--- a/source/libs/index/inc/index_fst_counting_writer.h
+++ b/source/libs/index/inc/index_fst_counting_writer.h
@@ -34,8 +34,14 @@ typedef struct WriterCtx {
   int (*flush)(struct WriterCtx *ctx);
   WriterType type; 
   union {
-    int fd;
-    void *mem;
+    struct {
+      int fd; 
+      bool readOnly;
+    } file; 
+    struct {
+      int32_t capa;
+      char *buf;
+    } mem;
   };
   int32_t offset;
   int32_t limit;
@@ -45,7 +51,7 @@ static int writeCtxDoWrite(WriterCtx *ctx, uint8_t *buf, int len);
 static int writeCtxDoRead(WriterCtx *ctx, uint8_t *buf, int len);
 static int writeCtxDoFlush(WriterCtx *ctx);
 
-WriterCtx* writerCtxCreate(WriterType type, bool readOnly);
+WriterCtx* writerCtxCreate(WriterType type, const char *path, bool readOnly, int32_t capacity);
 void writerCtxDestroy(WriterCtx *w);
 
 typedef uint32_t CheckSummer;
@@ -66,7 +72,7 @@ int fstCountingWriterFlush(FstCountingWriter *write);
 
 uint32_t fstCountingWriterMaskedCheckSum(FstCountingWriter *write);
 
-FstCountingWriter *fstCountingWriterCreate(void *wtr, bool readOnly);
+FstCountingWriter *fstCountingWriterCreate(void *wtr);
 void fstCountingWriterDestroy(FstCountingWriter *w); 
 
 
diff --git a/source/libs/index/inc/index_tfile.h b/source/libs/index/inc/index_tfile.h
index c3f4bd25e5..979c0b0639 100644
--- a/source/libs/index/inc/index_tfile.h
+++ b/source/libs/index/inc/index_tfile.h
@@ -18,23 +18,81 @@
 #include "index.h"
 #include "indexInt.h"
 #include "tlockfree.h"
-#include "tskiplist.h"
+#include "index_tfile.h"
+#include "index_fst_counting_writer.h"
+#include "index_fst.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-typedef struct IndexTFile {
+  
+
+typedef struct TFileCacheKey {
+  uint64_t   suid;
+  uint8_t    colType;
+  int32_t    version;
+  const char *colName;
+  int32_t    nColName;
+} TFileCacheKey; 
+
+
+// table cache
+// refactor to LRU cache later
+typedef struct TFileCache {
+  SHashObj *tableCache;        
+  int16_t  capacity;
+  // add more param  
+} TFileCache;
+
+
+typedef struct TFileWriter {
+  FstBuilder *fb;
+  WriterCtx  *wc; 
+} TFileWriter;
+
+typedef struct TFileReader {
   T_REF_DECLARE() 
+  Fst *fst;
+  
+} TFileReader; 
+
+typedef struct IndexTFile {
+  char *path;
+  TFileReader *tb;
+  TFileWriter *tw;      
 } IndexTFile;
 
+typedef struct TFileWriterOpt {
+  uint64_t suid;
+  int8_t   colType;
+  char     *colName;  
+  int32_t  nColName; 
+  int32_t  version;
+} TFileWriterOpt; 
 
+typedef struct TFileReaderOpt {
+  uint64_t suid; 
+  char     *colName;
+  int32_t  nColName; 
+  
+} TFileReaderOpt;
+
+// tfile cache 
+TFileCache *tfileCacheCreate();
+void tfileCacheDestroy(TFileCache *tcache);
+TFileReader* tfileCacheGet(TFileCache *tcache, TFileCacheKey *key);
+void tfileCachePut(TFileCache *tcache, TFileCacheKey *key, TFileReader *reader);
+  
+TFileWriter *tfileWriterCreate(const char *suid, const char *colName);
 
 IndexTFile *indexTFileCreate();
 
+int indexTFilePut(void *tfile, SIndexTerm *term,  uint64_t uid); 
 
 int indexTFileSearch(void *tfile, SIndexTermQuery *query, SArray *result);
 
+
 #ifdef __cplusplus
 }
 
diff --git a/source/libs/index/inc/index_util.h b/source/libs/index/inc/index_util.h
new file mode 100644
index 0000000000..4ab517ecfa
--- /dev/null
+++ b/source/libs/index/inc/index_util.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_UTIL_H__
+#define __INDEX_UTIL_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define SERIALIZE_MEM_TO_BUF(buf, key, mem) \
+  do { \
+   memcpy((void *)buf, (void *)(&key->mem), sizeof(key->mem)); \
+   buf += sizeof(key->mem);  \
+  } while (0)
+
+#define SERIALIZE_STR_MEM_TO_BUF(buf, key, mem, len) \
+  do { \
+    memcpy((void *)buf, (void *)key->mem, len); \
+    buf += len; \
+  } while (0)
+
+#define SERIALIZE_VAR_TO_BUF(buf, var, type) \
+  do { \
+     type c = var; \
+     assert(sizeof(var) == sizeof(type));\
+     memcpy((void *)buf, (void *)&c, sizeof(c)); \
+     buf += sizeof(c); \
+  } while (0)
+
+#define SERIALIZE_STR_VAR_TO_BUF(buf, var, len) \
+  do { \
+      memcpy((void *)buf, (void *)var, len); \
+      buf += len;\
+  } while (0)
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/source/libs/index/src/index_cache.c b/source/libs/index/src/index_cache.c
index 3c52275a4c..5813c99164 100644
--- a/source/libs/index/src/index_cache.c
+++ b/source/libs/index/src/index_cache.c
@@ -15,6 +15,7 @@
 
 #include "index_cache.h"
 #include "tcompare.h"
+#include "index_util.h"
 
 #define MAX_INDEX_KEY_LEN 256// test only, change later
 
@@ -110,35 +111,22 @@ int indexCachePut(void *cache, SIndexTerm *term, int16_t colId, int32_t version,
   if (cache == NULL) { return -1;} 
 
   IndexCache *pCache = cache;
-
   // encode data
   int32_t total = CACHE_KEY_LEN(term); 
-
   char *buf = calloc(1, total); 
   char *p   = buf;
 
-  memcpy(p, &total, sizeof(total)); 
-  p += sizeof(total);
+  SERIALIZE_VAR_TO_BUF(p, total,int32_t);
+  SERIALIZE_VAR_TO_BUF(p, colId, int16_t);
 
-  memcpy(p, &colId, sizeof(colId));   
-  p += sizeof(colId);
-
-  memcpy(p, &term->colType, sizeof(term->colType));
-  p += sizeof(term->colType);
+  SERIALIZE_MEM_TO_BUF(p, term, colType);
+  SERIALIZE_MEM_TO_BUF(p, term, nColVal); 
+  SERIALIZE_STR_MEM_TO_BUF(p, term, colVal, term->nColVal); 
   
-  memcpy(p, &term->nColVal, sizeof(term->nColVal));
-  p += sizeof(term->nColVal);
-  memcpy(p, term->colVal, term->nColVal); 
-  p += term->nColVal;
+  SERIALIZE_VAR_TO_BUF(p, version, int32_t);
+  SERIALIZE_VAR_TO_BUF(p, uid, uint64_t); 
 
-  memcpy(p, &version, sizeof(version));
-  p += sizeof(version);
-
-  memcpy(p, &uid, sizeof(uid));  
-  p += sizeof(uid);
-
-  memcpy(p, &term->operType, sizeof(term->operType));
-  p += sizeof(term->operType); 
+  SERIALIZE_MEM_TO_BUF(p, term, operType);
 
   tSkipListPut(pCache->skiplist, (void *)buf);  
   return 0;
diff --git a/source/libs/index/src/index_fst.c b/source/libs/index/src/index_fst.c
index 7aaa498864..0f00aacf3b 100644
--- a/source/libs/index/src/index_fst.c
+++ b/source/libs/index/src/index_fst.c
@@ -779,7 +779,7 @@ FstBuilder *fstBuilderCreate(void *w, FstType ty) {
   if (NULL == b) { return b; }
 
    
-  b->wrt        = fstCountingWriterCreate(w, false);
+  b->wrt        = fstCountingWriterCreate(w);
   b->unfinished = fstUnFinishedNodesCreate();   
   b->registry   = fstRegistryCreate(10000, 2) ;
   b->last       = fstSliceCreate(NULL, 0);
diff --git a/source/libs/index/src/index_fst_counting_writer.c b/source/libs/index/src/index_fst_counting_writer.c
index 9ec346cebc..3497b9703d 100644
--- a/source/libs/index/src/index_fst_counting_writer.c
+++ b/source/libs/index/src/index_fst_counting_writer.c
@@ -23,9 +23,9 @@ static int writeCtxDoWrite(WriterCtx *ctx, uint8_t *buf, int len) {
   }
 
   if (ctx->type == TFile) {
-    assert(len == tfWrite(ctx->fd, buf, len));
+    assert(len == tfWrite(ctx->file.fd, buf, len));
   } else {
-    memcpy(ctx->mem + ctx->offset, buf, len);
+    memcpy(ctx->mem.buf+ ctx->offset, buf, len);
   } 
   ctx->offset += len;
   return len;
@@ -33,9 +33,9 @@ static int writeCtxDoWrite(WriterCtx *ctx, uint8_t *buf, int len) {
 static int writeCtxDoRead(WriterCtx *ctx, uint8_t *buf, int len) {
   int nRead = 0; 
   if (ctx->type == TFile) {
-    nRead = tfRead(ctx->fd, buf, len);
+    nRead = tfRead(ctx->file.fd, buf, len);
   } else {
-    memcpy(buf, ctx->mem + ctx->offset, len);
+    memcpy(buf, ctx->mem.buf + ctx->offset, len);
   }
   ctx->offset += nRead;
 
@@ -44,63 +44,64 @@ static int writeCtxDoRead(WriterCtx *ctx, uint8_t *buf, int len) {
 static int writeCtxDoFlush(WriterCtx *ctx) {
   if (ctx->type == TFile) {
     //tfFsync(ctx->fd);
-    //tfFlush(ctx->fd);
+    //tfFlush(ctx->file.fd);
   } else {
     // do nothing
   }
   return 1;
 }
 
-WriterCtx* writerCtxCreate(WriterType type, bool readOnly) {     
+WriterCtx* writerCtxCreate(WriterType type, const char *path, bool readOnly, int32_t capacity) {     
   WriterCtx *ctx = calloc(1, sizeof(WriterCtx));
   if (ctx == NULL) { return NULL; }
 
   ctx->type = type;
   if (ctx->type == TFile) {
-    tfInit();
     // ugly code, refactor later
+    ctx->file.readOnly = readOnly;
     if (readOnly == false) {
-      ctx->fd = tfOpenCreateWriteAppend(tmpFile);  
+      ctx->file.fd = tfOpenCreateWriteAppend(tmpFile);  
     } else {
-      ctx->fd = tfOpenReadWrite(tmpFile);
+      ctx->file.fd = tfOpenReadWrite(tmpFile);
     } 
-    if (ctx->fd < 0) {
+    if (ctx->file.fd < 0) {
       indexError("open file error %d", errno);       
     }
   } else if (ctx->type == TMemory) {
-    ctx->mem = calloc(1, DefaultMem * sizeof(uint8_t));
+    ctx->mem.buf  = calloc(1, sizeof(char) * capacity); 
+    ctx->mem.capa = capacity; 
   } 
   ctx->write = writeCtxDoWrite;
   ctx->read  = writeCtxDoRead;
   ctx->flush = writeCtxDoFlush;
 
   ctx->offset = 0;
-  ctx->limit  = DefaultMem;
+  ctx->limit  = capacity;
 
   return ctx;
 }
 void writerCtxDestroy(WriterCtx *ctx) {
   if (ctx->type == TMemory) {
-    free(ctx->mem);
+    free(ctx->mem.buf);
   } else {
-    tfClose(ctx->fd);    
-    tfCleanup();
+    tfClose(ctx->file.fd);    
   }
   free(ctx);
 }
 
 
-FstCountingWriter *fstCountingWriterCreate(void *wrt, bool readOnly) {
+FstCountingWriter *fstCountingWriterCreate(void *wrt) {
   FstCountingWriter *cw = calloc(1, sizeof(FstCountingWriter)); 
   if (cw == NULL) { return NULL; }
   
-  cw->wrt = (void *)(writerCtxCreate(TFile, readOnly)); 
+  cw->wrt = wrt;
+  //(void *)(writerCtxCreate(TFile, readOnly)); 
   return cw; 
 }
 void fstCountingWriterDestroy(FstCountingWriter *cw) {
   // free wrt object: close fd or free mem 
   fstCountingWriterFlush(cw);
-  writerCtxDestroy((WriterCtx *)(cw->wrt));
+  //writerCtxDestroy((WriterCtx *)(cw->wrt));
   free(cw);
 }
 
@@ -124,6 +125,7 @@ int fstCountingWriterRead(FstCountingWriter *write, uint8_t *buf, uint32_t len)
 } 
 
 uint32_t fstCountingWriterMaskedCheckSum(FstCountingWriter *write) {
+  
   return 0;
 }
 int fstCountingWriterFlush(FstCountingWriter *write) {
diff --git a/source/libs/index/src/index_tfile.c b/source/libs/index/src/index_tfile.c
index a1bba56391..81a7f9f443 100644
--- a/source/libs/index/src/index_tfile.c
+++ b/source/libs/index/src/index_tfile.c
@@ -14,6 +14,50 @@
  */
 
 #include "index_tfile.h"
+#include "index_fst.h"
+#include "index_util.h"
+
+
+
+static void tfileSerialCacheKey(TFileCacheKey *key, char *buf) {
+  SERIALIZE_MEM_TO_BUF(buf, key, suid);
+  SERIALIZE_VAR_TO_BUF(buf, '_', char); 
+  SERIALIZE_MEM_TO_BUF(buf, key, colType);
+  SERIALIZE_VAR_TO_BUF(buf, '_', char); 
+  SERIALIZE_MEM_TO_BUF(buf, key, version);
+  SERIALIZE_VAR_TO_BUF(buf, '_', char); 
+  SERIALIZE_STR_MEM_TO_BUF(buf, key, colName, key->nColName);
+}
+
+TFileCache *tfileCacheCreate() {
+  TFileCache *tcache = calloc(1, sizeof(TFileCache)); 
+  if (tcache == NULL) { return NULL; }
+  
+  tcache->tableCache = taosHashInit(8, taosGetDefaultHashFunction(TSDB_DATA_TYPE_BINARY), true, HASH_ENTRY_LOCK); 
+  tcache->capacity   = 64;
+  return tcache;
+}
+void tfileCacheDestroy(TFileCache *tcache) {
+  
+  free(tcache);    
+   
+}
+
+TFileReader *tfileCacheGet(TFileCache *tcache, TFileCacheKey *key) {
+  char buf[128] = {0}; 
+  tfileSerialCacheKey(key, buf);
+  TFileReader *reader = taosHashGet(tcache->tableCache, buf, strlen(buf)); 
+  return reader; 
+}
+void tfileCachePut(TFileCache *tcache, TFileCacheKey *key, TFileReader *reader) {
+  char buf[128] = {0};
+  tfileSerialCacheKey(key, buf);
+  taosHashPut(tcache->tableCache, buf, strlen(buf), &reader, sizeof(void *));     
+  return;
+} 
+
+
+
 
 IndexTFile *indexTFileCreate() {
   IndexTFile *tfile = calloc(1, sizeof(IndexTFile));   
@@ -22,10 +66,24 @@ IndexTFile *indexTFileCreate() {
 void IndexTFileDestroy(IndexTFile *tfile) {
   free(tfile); 
 }
+
+
 int indexTFileSearch(void *tfile, SIndexTermQuery *query, SArray *result) {
   IndexTFile *ptfile = (IndexTFile *)tfile;
+     
   return 0;
 }
+int indexTFilePut(void *tfile, SIndexTerm *term,  uint64_t uid) {
+  TFileWriterOpt wOpt = {.suid    = term->suid,
+                         .colType = term->colType,
+                         .colName = term->colName,
+                         .nColName= term->nColName,
+                         .version = 1}; 
+
+  
+   
+  return 0; 
+}
 
 
 
diff --git a/source/libs/index/test/indexTests.cc b/source/libs/index/test/indexTests.cc
index 9dff2e9ea0..9baabb9610 100644
--- a/source/libs/index/test/indexTests.cc
+++ b/source/libs/index/test/indexTests.cc
@@ -45,7 +45,7 @@ class FstWriter {
 class FstReadMemory {
   public:
    FstReadMemory(size_t size) {
-     _w    = fstCountingWriterCreate(NULL, true); 
+     _w    = fstCountingWriterCreate(NULL); 
      _size = size; 
      memset((void *)&_s, 0, sizeof(_s));
    }