diff --git a/source/dnode/vnode/CMakeLists.txt b/source/dnode/vnode/CMakeLists.txt
index 3489863f370c4226682bb62289f6cec4cb6c9e86..eb1fbac2c9e150bb8f612cc224e2ad96da2436a9 100644
--- a/source/dnode/vnode/CMakeLists.txt
+++ b/source/dnode/vnode/CMakeLists.txt
@@ -52,6 +52,7 @@ target_sources(
     "src/tsdb/tsdbDiskData.c"
     "src/tsdb/tsdbCompress.c"
     "src/tsdb/tsdbCompact.c"
+    "src/tsdb/tsdbMergeTree.c"
 
     # tq
     "src/tq/tq.c"
diff --git a/source/dnode/vnode/src/inc/tsdb.h b/source/dnode/vnode/src/inc/tsdb.h
index f3a2cd30794d4a2490ed81e2deb758c6142965bc..968cc7f297569e436a20815d3a075ab907ff4a14 100644
--- a/source/dnode/vnode/src/inc/tsdb.h
+++ b/source/dnode/vnode/src/inc/tsdb.h
@@ -620,6 +620,12 @@ struct SDataFReader {
   uint8_t *aBuf[3];
 };
 
+typedef struct {
+  int64_t suid;
+  int64_t uid;
+  TSDBROW row;
+} SRowInfo;
+
 // ========== inline functions ==========
 static FORCE_INLINE int32_t tsdbKeyCmprFn(const void *p1, const void *p2) {
   TSDBKEY *pKey1 = (TSDBKEY *)p1;
diff --git a/source/dnode/vnode/src/tsdb/tsdbCommit.c b/source/dnode/vnode/src/tsdb/tsdbCommit.c
index 0824faf390756f86a927b3d4912ae56de6394e3e..b227e97df6918f12ffa72e4393689bf007517fef 100644
--- a/source/dnode/vnode/src/tsdb/tsdbCommit.c
+++ b/source/dnode/vnode/src/tsdb/tsdbCommit.c
@@ -20,12 +20,6 @@ typedef struct {
   STSchema *pTSchema;
 } SSkmInfo;
 
-typedef struct {
-  int64_t suid;
-  int64_t uid;
-  TSDBROW row;
-} SRowInfo;
-
 typedef enum { MEMORY_DATA_ITER = 0, LAST_DATA_ITER } EDataIterT;
 
 typedef struct {
diff --git a/source/dnode/vnode/src/tsdb/tsdbMergeTree.c b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
new file mode 100644
index 0000000000000000000000000000000000000000..1d51025331e6418cf55787baa8e3686df0c311ab
--- /dev/null
+++ b/source/dnode/vnode/src/tsdb/tsdbMergeTree.c
@@ -0,0 +1,133 @@
+/*
+ * 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 "tsdb.h"
+
+// SLDataIter =================================================
+typedef struct {
+  SRBTreeNode node;
+  SBlockL    *pBlockL;
+  SRowInfo   *pRowInfo;
+
+  SDataFReader *pReader;
+  int32_t       iLast;
+  int8_t        backward;
+  SArray       *aBlockL;
+  int32_t       iBlockL;
+  SBlockData    bData;
+  int32_t       iRow;
+  SRowInfo      rInfo;
+} SLDataIter;
+
+int32_t tLDataIterOpen(SLDataIter *pIter, SDataFReader *pReader, int32_t iLast, int8_t backward) {
+  int32_t code = 0;
+
+  pIter->pReader = pReader;
+  pIter->iLast = iLast;
+  pIter->backward = backward;
+
+  pIter->aBlockL = taosArrayInit(0, sizeof(SBlockL));
+  if (pIter->aBlockL == NULL) {
+    code = TSDB_CODE_OUT_OF_MEMORY;
+    goto _exit;
+  }
+
+  code = tBlockDataCreate(&pIter->bData);
+  if (code) goto _exit;
+
+  code = tsdbReadBlockL(pReader, iLast, pIter->aBlockL);
+  if (code) goto _exit;
+
+  if (backward) {
+    pIter->iBlockL = taosArrayGetSize(pIter->aBlockL) - 1;
+  } else {
+    pIter->iBlockL = 0;
+  }
+
+_exit:
+  return code;
+}
+
+void tLDataIterClose(SLDataIter *pIter) {
+  tBlockDataDestroy(&pIter->bData, 1);
+  taosArrayDestroy(pIter->aBlockL);
+}
+
+extern int32_t tsdbReadLastBlockEx(SDataFReader *pReader, int32_t iLast, SBlockL *pBlockL, SBlockData *pBlockData);
+
+void tLDataIterNextBlock(SLDataIter *pIter) {
+  if (pIter->backward) {
+    pIter->iBlockL--;
+  } else {
+    pIter->iBlockL++;
+  }
+
+  if (pIter->iBlockL >= 0 && pIter->iBlockL < taosArrayGetSize(pIter->aBlockL)) {
+    pIter->pBlockL = (SBlockL *)taosArrayGet(pIter->aBlockL, pIter->iBlockL);
+  } else {
+    pIter->pBlockL = NULL;
+  }
+}
+
+int32_t tLDataIterNextRow(SLDataIter *pIter) {
+  int32_t code = 0;
+
+  if (pIter->backward) {
+    pIter->iRow--;
+    if (pIter->iRow < 0) {
+      pIter->iBlockL--;
+
+      if (pIter->iBlockL >= 0) {
+        code = tsdbReadLastBlockEx(pIter->pReader, pIter->iLast, taosArrayGet(pIter->aBlockL, pIter->iBlockL),
+                                   &pIter->bData);
+        if (code) goto _exit;
+      } else {
+        // TODO: no more data here
+      }
+    }
+  } else {
+    pIter->iRow++;
+    if (pIter->iRow >= pIter->bData.nRow) {
+      pIter->iBlockL++;
+      if (pIter->iBlockL < taosArrayGetSize(pIter->aBlockL)) {
+        code = tsdbReadLastBlockEx(pIter->pReader, pIter->iLast, taosArrayGet(pIter->aBlockL, pIter->iBlockL),
+                                   &pIter->bData);
+        if (code) goto _exit;
+      } else {
+        // TODO: not more data
+        goto _exit;
+      }
+    }
+  }
+
+  pIter->rInfo.suid = pIter->bData.suid;
+  pIter->rInfo.uid = pIter->bData.uid;
+  pIter->rInfo.row = tsdbRowFromBlockData(&pIter->bData, pIter->iRow);
+
+_exit:
+  return code;
+}
+
+SRowInfo *tLDataIterGet(SLDataIter *pIter) {
+  // TODO
+  return NULL;
+}
+
+// SMergeTree =================================================
+typedef struct {
+  int8_t       backward;
+  SRBTreeNode *pNode;
+  SRBTree      rbt;
+} SMergeTree;