diff --git a/include/util/tarray2.h b/include/util/tarray2.h
index db0fc759768cdaee63541df04e8c009905f1e07a..9b67c84563569d657131929a0185c8d70e4b3ce4 100644
--- a/include/util/tarray2.h
+++ b/include/util/tarray2.h
@@ -67,13 +67,15 @@ static FORCE_INLINE int32_t tarray2_make_room(  //
   return 0;
 }
 
-#define TARRAY2_INIT(a) \
-  do {                  \
-    (a)->size = 0;      \
-    (a)->capacity = 0;  \
-    (a)->data = NULL;   \
+#define TARRAY2_INIT_EX(a, size_, capacity_, data_) \
+  do {                                              \
+    (a)->size = (size_);                            \
+    (a)->capacity = (capacity_);                    \
+    (a)->data = (data_);                            \
   } while (0)
 
+#define TARRAY2_INIT(a) TARRAY2_INIT_EX(a, 0, 0, NULL)
+
 #define TARRAY2_FREE(a)          \
   do {                           \
     if ((a)->data) {             \
diff --git a/source/dnode/vnode/src/tsdb/dev/inc/tsdbSttFReaderWriter.h b/source/dnode/vnode/src/tsdb/dev/inc/tsdbSttFReaderWriter.h
index 65e95aa88f9f0100f4b66a50c8e57e9a9927694a..cf7d0765eb1f318eab08da6a454238e8256434da 100644
--- a/source/dnode/vnode/src/tsdb/dev/inc/tsdbSttFReaderWriter.h
+++ b/source/dnode/vnode/src/tsdb/dev/inc/tsdbSttFReaderWriter.h
@@ -13,43 +13,49 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include "tsdbFS.h"
+#include "tsdbUtil.h"
+
 #ifndef _TSDB_STT_FILE_WRITER_H
 #define _TSDB_STT_FILE_WRITER_H
 
-#include "tsdbFS.h"
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 typedef TARRAY2(SSttBlk) TSttBlkArray;
+typedef TARRAY2(SDelBlk) TDelBlkArray;
+typedef TARRAY2(STbStatisBlk) TStatisBlkArray;
 
 // SSttFileReader ==========================================
-typedef struct SSttFSegReader       SSttFSegReader;
 typedef struct SSttFileReader       SSttFileReader;
 typedef struct SSttFileReaderConfig SSttFileReaderConfig;
+typedef struct SSttSegReader        SSttSegReader;
+typedef TARRAY2(SSttSegReader *) TSttSegReaderArray;
 
 // SSttFileReader
-int32_t tsdbSttFReaderOpen(const SSttFileReaderConfig *config, SSttFileReader **ppReader);
-int32_t tsdbSttFReaderClose(SSttFileReader **ppReader);
+int32_t tsdbSttFReaderOpen(const SSttFileReaderConfig *config, SSttFileReader **reader);
+int32_t tsdbSttFReaderClose(SSttFileReader **reader);
+int32_t tsdbSttFReaderGetSegReader(SSttFileReader *reader, const TSttSegReaderArray **segReaderArray);
+
+// SSttSegReader
+int32_t tsdbSttFReadBloomFilter(SSttSegReader *reader, const void *pFilter);
 
-// SSttFSegReader
-int32_t tsdbSttFSegReaderOpen(SSttFileReader *pReader, SSttFSegReader **ppSegReader, int32_t nSegment);
-int32_t tsdbSttFSegReaderClose(SSttFSegReader **ppSegReader);
-int32_t tsdbSttFSegReadBloomFilter(SSttFSegReader *pSegReader, const void *pFilter);
-int32_t tsdbSttFSegReadStatisBlk(SSttFSegReader *pSegReader, const SArray *pStatis);
-int32_t tsdbSttFSegReadDelBlk(SSttFSegReader *pSegReader, const SArray *pDelBlk);
-int32_t tsdbSttFSegReadSttBlk(SSttFSegReader *pSegReader, const SArray *pSttBlk);
-int32_t tsdbSttFSegReadStatisBlock(SSttFSegReader *pSegReader, const void *pBlock);
-int32_t tsdbSttFSegReadDelBlock(SSttFSegReader *pSegReader, const void *pBlock);
-int32_t tsdbSttFSegReadSttBlock(SSttFSegReader *pSegReader, const void *pBlock);
+int32_t tsdbSttFReadSttBlk(SSttSegReader *reader, const TSttBlkArray **sttBlkArray);
+int32_t tsdbSttFReadDelBlk(SSttSegReader *reader, const TDelBlkArray **delBlkArray);
+int32_t tsdbSttFReadStatisBlk(SSttSegReader *reader, const TStatisBlkArray **statisBlkArray);
+
+int32_t tsdbSttFReadSttBlock(SSttSegReader *reader, const SSttBlk *sttBlk, SBlockData *bData);
+int32_t tsdbSttFReadDelBlock(SSttSegReader *reader, const SDelBlk *delBlk, SDelBlock *dData);
+int32_t tsdbSttFReadStatisBlock(SSttSegReader *reader, const STbStatisBlk *statisBlk, STbStatisBlock *sData);
 
 struct SSttFileReaderConfig {
-  STsdb    *pTsdb;
+  STsdb    *tsdb;
   SSkmInfo *pSkmTb;
   SSkmInfo *pSkmRow;
   uint8_t **aBuf;
-  // TODO
+  int32_t   szPage;
+  STFile    file;
 };
 
 // SSttFileWriter ==========================================
diff --git a/source/dnode/vnode/src/tsdb/dev/tsdbMerge.c b/source/dnode/vnode/src/tsdb/dev/tsdbMerge.c
index 69a726f7d1e57abdce42bf81786c23cbc3130dd5..b4176d9526f0983d66bcf77327d9550ce31b7fca 100644
--- a/source/dnode/vnode/src/tsdb/dev/tsdbMerge.c
+++ b/source/dnode/vnode/src/tsdb/dev/tsdbMerge.c
@@ -199,7 +199,7 @@ static int32_t tsdbMergeFileSetBegin(SMerger *merger) {
       // open the reader
       SSttFileReader      *reader;
       SSttFileReaderConfig config = {
-          .pTsdb = merger->tsdb,
+          .tsdb = merger->tsdb,
           // TODO
       };
       code = tsdbSttFReaderOpen(&config, &reader);
diff --git a/source/dnode/vnode/src/tsdb/dev/tsdbSttFReaderWriter.c b/source/dnode/vnode/src/tsdb/dev/tsdbSttFReaderWriter.c
index e2f241d8f45c7755c886bc358ba032681cd7daf5..669368c8618bafe5b5193da3d763d103c23f986c 100644
--- a/source/dnode/vnode/src/tsdb/dev/tsdbSttFReaderWriter.c
+++ b/source/dnode/vnode/src/tsdb/dev/tsdbSttFReaderWriter.c
@@ -13,7 +13,7 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "dev.h"
+#include "inc/tsdbSttFReaderWriter.h"
 
 typedef struct {
   int64_t   prevFooter;
@@ -23,73 +23,221 @@ typedef struct {
 
 // SSttFReader ============================================================
 struct SSttFileReader {
-  SSttFileReaderConfig *config;
-  // TODO
+  SSttFileReaderConfig config;
+  TSttSegReaderArray   segReaderArray;
+  STsdbFD             *fd;
+};
+
+struct SSttSegReader {
+  SSttFileReader *reader;
+
+  struct {
+    bool bloomFilterLoaded;
+    bool sttBlkLoaded;
+    bool delBlkLoaded;
+    bool statisBlkLoaded;
+  } ctx;
+
+  SFSttFooter     footer;
+  void           *bloomFilter;
+  TSttBlkArray    sttBlkArray;
+  TDelBlkArray    delBlkArray;
+  TStatisBlkArray statisBlkArray;
 };
 
 // SSttFileReader
-int32_t tsdbSttFReaderOpen(const SSttFileReaderConfig *config, SSttFileReader **ppReader) {
+static int32_t tsdbSttSegReaderOpen(SSttFileReader *reader, int64_t offset, SSttSegReader **segReader) {
   int32_t code = 0;
-  // TODO
+  int32_t lino = 0;
+  int32_t vid = TD_VID(reader->config.tsdb->pVnode);
+
+  ASSERT(offset >= TSDB_FHDR_SIZE);
+
+  segReader[0] = taosMemoryCalloc(1, sizeof(*segReader[0]));
+  if (segReader[0] == NULL) return TSDB_CODE_OUT_OF_MEMORY;
+
+  segReader[0]->reader = reader;
+  code = tsdbReadFile(reader->fd, offset, (uint8_t *)(&segReader[0]->footer), sizeof(segReader[0]->footer));
+  TSDB_CHECK_CODE(code, lino, _exit);
+
+_exit:
+  if (code) {
+    tsdbError("vgId:%d %s failed at line %d since %s", vid, __func__, lino, tstrerror(code));
+    taosMemoryFree(segReader[0]);
+    segReader[0] = NULL;
+  }
   return code;
 }
 
-int32_t tsdbSttFReaderClose(SSttFileReader **ppReader) {
-  int32_t code = 0;
-  // TODO
-  return code;
+static int32_t tsdbSttSegReaderClose(SSttSegReader **segReader) {
+  if (!segReader[0]) return 0;
+
+  if (segReader[0]->ctx.bloomFilterLoaded) {
+    // TODO
+  }
+  if (segReader[0]->ctx.sttBlkLoaded) {
+    TARRAY2_FREE(&segReader[0]->sttBlkArray);
+  }
+  if (segReader[0]->ctx.delBlkLoaded) {
+    TARRAY2_FREE(&segReader[0]->delBlkArray);
+  }
+  if (segReader[0]->ctx.statisBlkLoaded) {
+    TARRAY2_FREE(&segReader[0]->statisBlkArray);
+  }
+  taosMemoryFree(segReader[0]);
+  segReader[0] = NULL;
+  return 0;
 }
 
-// SSttFSegReader
-int32_t tsdbSttFSegReaderOpen(SSttFileReader *pReader, SSttFSegReader **ppSegReader, int32_t nSegment) {
+int32_t tsdbSttFReaderOpen(const SSttFileReaderConfig *config, SSttFileReader **reader) {
   int32_t code = 0;
-  // TODO
+  int32_t lino = 0;
+  int32_t vid = TD_VID(config->tsdb->pVnode);
+
+  reader[0] = taosMemoryCalloc(1, sizeof(*reader[0]));
+  if (reader[0] == NULL) return TSDB_CODE_OUT_OF_MEMORY;
+
+  reader[0]->config = config[0];
+  TARRAY2_INIT(&reader[0]->segReaderArray);
+
+  // open file
+  char fname[TSDB_FILENAME_LEN];
+  tsdbTFileName(config->tsdb, &config->file, fname);
+  code = tsdbOpenFile(fname, config->szPage, TD_FILE_READ, &reader[0]->fd);
+  TSDB_CHECK_CODE(code, lino, _exit);
+
+  // open each segment reader
+  int64_t size = config->file.size;
+  while (size > 0) {
+    SSttSegReader *segReader;
+
+    code = tsdbSttSegReaderOpen(reader[0], size - sizeof(SFSttFooter), &segReader);
+    TSDB_CHECK_CODE(code, lino, _exit);
+
+    code = TARRAY2_APPEND(&reader[0]->segReaderArray, segReader);
+    TSDB_CHECK_CODE(code, lino, _exit);
+
+    size = segReader->footer.prevFooter;
+  }
+
+  ASSERT(TARRAY2_SIZE(&reader[0]->segReaderArray) == config->file.stt.nseg);
+
+_exit:
+  if (code) {
+    tsdbError("vgId:%d %s failed at line %d since %s", vid, __func__, lino, tstrerror(code));
+    tsdbSttFReaderClose(reader);
+  }
   return code;
 }
 
-int32_t tsdbSttFSegReaderClose(SSttFSegReader **ppSegReader) {
-  int32_t code = 0;
-  // TODO
-  return code;
+int32_t tsdbSttFReaderClose(SSttFileReader **reader) {
+  tsdbCloseFile(&reader[0]->fd);
+  TARRAY2_CLEAR_FREE(&reader[0]->segReaderArray, tsdbSttSegReaderClose);
+  taosMemoryFree(reader[0]);
+  reader[0] = NULL;
+  return 0;
 }
 
-int32_t tsdbSttFSegReadBloomFilter(SSttFSegReader *pSegReader, const void *pFilter) {
-  int32_t code = 0;
-  // TODO
-  return code;
+int32_t tsdbSttFReaderGetSegReader(SSttFileReader *reader, const TSttSegReaderArray **segReaderArray) {
+  segReaderArray[0] = &reader->segReaderArray;
+  return 0;
 }
 
-int32_t tsdbSttFSegReadStatisBlk(SSttFSegReader *pSegReader, const SArray *pStatis) {
+// SSttFSegReader
+int32_t tsdbSttFReadBloomFilter(SSttSegReader *reader, const void *pFilter) {
   int32_t code = 0;
   // TODO
   return code;
 }
 
-int32_t tsdbSttFSegReadDelBlk(SSttFSegReader *pSegReader, const SArray *pDelBlk) {
-  int32_t code = 0;
-  // TODO
-  return code;
+int32_t tsdbSttFReadStatisBlk(SSttSegReader *reader, const TStatisBlkArray **statisBlkArray) {
+  if (!reader->ctx.statisBlkLoaded) {
+    SFDataPtr fptr = reader->footer.dict[2];
+    if (fptr.size > 0) {
+      ASSERT(fptr.size % sizeof(STbStatisBlk) == 0);
+
+      int32_t size = fptr.size / sizeof(STbStatisBlk);
+      void   *data = taosMemoryMalloc(fptr.size);
+      if (!data) return TSDB_CODE_OUT_OF_MEMORY;
+
+      int32_t code = tsdbReadFile(reader->reader->fd, fptr.offset, data, fptr.size);
+      if (code) return code;
+
+      TARRAY2_INIT_EX(&reader->statisBlkArray, size, size, data);
+    } else {
+      TARRAY2_INIT(&reader->statisBlkArray);
+    }
+
+    reader->ctx.statisBlkLoaded = true;
+  }
+
+  statisBlkArray[0] = &reader->statisBlkArray;
+  return 0;
 }
 
-int32_t tsdbSttFSegReadSttBlk(SSttFSegReader *pSegReader, const SArray *pSttBlk) {
-  int32_t code = 0;
-  // TODO
-  return code;
+int32_t tsdbSttFReadDelBlk(SSttSegReader *reader, const TDelBlkArray **delBlkArray) {
+  if (!reader->ctx.delBlkLoaded) {
+    SFDataPtr fptr = reader->footer.dict[3];
+    if (fptr.size > 0) {
+      ASSERT(fptr.size % sizeof(SDelBlk) == 0);
+
+      int32_t size = fptr.size / sizeof(SDelBlk);
+      void   *data = taosMemoryMalloc(fptr.size);
+      if (!data) return TSDB_CODE_OUT_OF_MEMORY;
+
+      int32_t code = tsdbReadFile(reader->reader->fd, fptr.offset, data, fptr.size);
+      if (code) return code;
+
+      TARRAY2_INIT_EX(&reader->delBlkArray, size, size, data);
+    } else {
+      TARRAY2_INIT(&reader->delBlkArray);
+    }
+
+    reader->ctx.delBlkLoaded = true;
+  }
+
+  delBlkArray[0] = &reader->delBlkArray;
+  return 0;
+}
+
+int32_t tsdbSttFReadSttBlk(SSttSegReader *reader, const TSttBlkArray **sttBlkArray) {
+  if (!reader->ctx.sttBlkLoaded) {
+    SFDataPtr fptr = reader->footer.dict[1];
+    if (fptr.size > 0) {
+      ASSERT(fptr.size % sizeof(SSttBlk) == 0);
+
+      int32_t size = fptr.size / sizeof(SSttBlk);
+      void   *data = taosMemoryMalloc(fptr.size);
+      if (!data) return TSDB_CODE_OUT_OF_MEMORY;
+
+      int32_t code = tsdbReadFile(reader->reader->fd, fptr.offset, data, fptr.size);
+      if (code) return code;
+
+      TARRAY2_INIT_EX(&reader->sttBlkArray, size, size, data);
+    } else {
+      TARRAY2_INIT(&reader->sttBlkArray);
+    }
+
+    reader->ctx.sttBlkLoaded = true;
+  }
+
+  sttBlkArray[0] = &reader->sttBlkArray;
+  return 0;
 }
 
-int32_t tsdbSttFSegReadStatisBlock(SSttFSegReader *pSegReader, const void *pBlock) {
+int32_t tsdbSttFReadSttBlock(SSttSegReader *reader, const SSttBlk *sttBlk, SBlockData *bData) {
   int32_t code = 0;
   // TODO
   return code;
 }
 
-int32_t tsdbSttFSegReadDelBlock(SSttFSegReader *pSegReader, const void *pBlock) {
+int32_t tsdbSttFReadDelBlock(SSttSegReader *reader, const SDelBlk *delBlk, SDelBlock *dData) {
   int32_t code = 0;
   // TODO
   return code;
 }
 
-int32_t tsdbSttFSegReadSttBlock(SSttFSegReader *pSegReader, const void *pBlock) {
+int32_t tsdbSttFReadStatisBlock(SSttSegReader *reader, const STbStatisBlk *statisBlk, STbStatisBlock *sData) {
   int32_t code = 0;
   // TODO
   return code;