diff --git a/source/dnode/vnode/src/inc/tsdb.h b/source/dnode/vnode/src/inc/tsdb.h
index 7546b0943e5642317a735626b01a2e0c393e2751..98a3ee9fdb2b871995c1306ea70d8af8049fd8ce 100644
--- a/source/dnode/vnode/src/inc/tsdb.h
+++ b/source/dnode/vnode/src/inc/tsdb.h
@@ -633,9 +633,10 @@ typedef struct SMergeTree {
   struct SLDataIter *pIter;
 } SMergeTree;
 
-int32_t tMergeTreeOpen(SMergeTree *pMTree, int8_t backward, SDataFReader* pFReader, uint64_t uid, STimeWindow* pTimeWindow, SVersionRange* pVerRange);
-void tMergeTreeAddIter(SMergeTree *pMTree, struct SLDataIter *pIter);
-bool tMergeTreeNext(SMergeTree *pMTree);
+int32_t tMergeTreeOpen(SMergeTree *pMTree, int8_t backward, SDataFReader *pFReader, uint64_t uid,
+                       STimeWindow *pTimeWindow, SVersionRange *pVerRange);
+void    tMergeTreeAddIter(SMergeTree *pMTree, struct SLDataIter *pIter);
+bool    tMergeTreeNext(SMergeTree *pMTree);
 TSDBROW tMergeTreeGetRow(SMergeTree *pMTree);
 void    tMergeTreeClose(SMergeTree *pMTree);
 
diff --git a/source/dnode/vnode/src/tsdb/tsdbReaderWriter.c b/source/dnode/vnode/src/tsdb/tsdbReaderWriter.c
index dbaf9b234c5a7bca7b41c2f5ca943234c05e129f..a969a3c080a915007e08e6cdac4a54a248a0fdb2 100644
--- a/source/dnode/vnode/src/tsdb/tsdbReaderWriter.c
+++ b/source/dnode/vnode/src/tsdb/tsdbReaderWriter.c
@@ -1608,3 +1608,135 @@ _err:
   tsdbError("vgId:%d, tsdb DFileSet copy failed since %s", TD_VID(pTsdb->pVnode), tstrerror(code));
   return code;
 }
+
+// =============== PAGE-WISE FILE ===============
+typedef struct {
+  TdFilePtr pFD;
+  int32_t   szPage;
+  int32_t   nBuf;
+  uint8_t  *pBuf;
+  int64_t   pgno;
+} STsdbFD;
+
+int32_t tsdbOpenFile(const char *path, int32_t opt, STsdbFD *pFD) {
+  int32_t code = 0;
+
+  pFD->pFD = taosOpenFile(path, opt);
+  if (pFD->pFD == NULL) {
+    code = TAOS_SYSTEM_ERROR(errno);
+    goto _exit;
+  }
+
+  pFD->szPage = 4096;
+  pFD->nBuf = 0;
+  pFD->pBuf = taosMemoryMalloc(pFD->szPage);
+  if (pFD->pBuf == NULL) {
+    code = TSDB_CODE_OUT_OF_MEMORY;
+    goto _exit;
+  }
+
+_exit:
+  return code;
+}
+
+void tsdbCloseFile(STsdbFD *pFD) {
+  taosMemoryFree(pFD->pBuf);
+  taosCloseFile(&pFD->pFD);
+}
+
+int32_t tsdbSyncFile(STsdbFD *pFD) {
+  int32_t code = 0;
+
+  if (taosFsyncFile(pFD->pFD) < 0) {
+    code = TAOS_SYSTEM_ERROR(errno);
+    goto _exit;
+  }
+
+_exit:
+  return code;
+}
+
+int32_t tsdbWriteFile(STsdbFD *pFD, uint8_t *pBuf, int32_t nBuf) {
+  int32_t code = 0;
+
+  int32_t n = 0;
+  while (n < nBuf) {
+    int32_t remain = pFD->szPage - pFD->nBuf - sizeof(TSCKSUM);
+    int32_t size = TMIN(remain, nBuf - n);
+
+    memcpy(pFD->pBuf + pFD->nBuf, pBuf + n, size);
+    n += size;
+    pFD->nBuf += size;
+
+    if (pFD->nBuf + sizeof(TSCKSUM) == pFD->szPage) {
+      taosCalcChecksumAppend(0, pFD->pBuf, pFD->szPage);
+
+      int64_t n = taosWriteFile(pFD->pFD, pFD->pBuf, pFD->szPage);
+      if (n < 0) {
+        code = TAOS_SYSTEM_ERROR(errno);
+        goto _exit;
+      }
+
+      pFD->nBuf = 0;
+    }
+  }
+
+_exit:
+  return code;
+}
+
+static int32_t tsdbReadFilePage(STsdbFD *pFD, int64_t pgno) {
+  int32_t code = 0;
+
+  int64_t n = taosLSeekFile(pFD->pFD, pgno * pFD->szPage, SEEK_SET);
+  if (n < 0) {
+    code = TAOS_SYSTEM_ERROR(errno);
+    goto _exit;
+  }
+
+  n = taosReadFile(pFD->pFD, pFD->pBuf, pFD->szPage);
+  if (n < 0) {
+    code = TAOS_SYSTEM_ERROR(errno);
+    goto _exit;
+  } else if (n < pFD->szPage) {
+    code = TSDB_CODE_FILE_CORRUPTED;
+    goto _exit;
+  }
+
+  if (!taosCheckChecksumWhole(pFD->pBuf, pFD->szPage)) {
+    code = TSDB_CODE_FILE_CORRUPTED;
+    goto _exit;
+  }
+
+  pFD->pgno = pgno;
+
+_exit:
+  return code;
+}
+
+int64_t tsdbReadFile(STsdbFD *pFD, int64_t offset, uint8_t *pBuf, int64_t count) {
+  int32_t code = 0;
+
+  int64_t pgno = offset / pFD->szPage;
+  int64_t n = 0;
+  if (pFD->pgno == pgno) {
+    int64_t bOff = offset % pFD->szPage;
+    int64_t nRead = TMIN(pFD->szPage - bOff - sizeof(TSCKSUM), count);
+    memcpy(pBuf + n, pFD->pBuf + bOff, nRead);
+    n = nRead;
+  }
+
+  while (n < count) {
+    code = tsdbReadFilePage(pFD, pgno);
+    if (code) goto _exit;
+
+    pgno++;
+
+    int64_t nRead = TMIN(pFD->szPage - sizeof(TSCKSUM), count - n);
+    memcpy(pBuf + n, pFD->pBuf, nRead);
+    n += nRead;
+  }
+
+_exit:
+  return code;
+}
\ No newline at end of file