diff --git a/include/server/vnode/tsdb/tsdb.h b/include/server/vnode/tsdb/tsdb.h
index 949ac679ae..e92205378a 100644
--- a/include/server/vnode/tsdb/tsdb.h
+++ b/include/server/vnode/tsdb/tsdb.h
@@ -16,15 +16,14 @@
 #ifndef _TD_TSDB_H_
 #define _TD_TSDB_H_
 
-#include "impl/tsdbImpl.h"
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 // TYPES EXPOSED
-typedef struct STsdb        STsdb;
-typedef struct STsdbOptions STsdbOptions;
+typedef struct STsdb             STsdb;
+typedef struct STsdbOptions      STsdbOptions;
+typedef struct STsdbMemAllocator STsdbMemAllocator;
 
 // STsdb
 STsdb *tsdbOpen(const char *path, const STsdbOptions *);
@@ -35,6 +34,12 @@ void   tsdbRemove(const char *path);
 int  tsdbOptionsInit(STsdbOptions *);
 void tsdbOptionsClear(STsdbOptions *);
 
+/* ------------------------ STRUCT DEFINITIONS ------------------------ */
+struct STsdbOptions {
+  uint64_t lruCacheSize;
+  /* TODO */
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/dnode/vnode/impl/inc/vnodeDef.h b/source/dnode/vnode/impl/inc/vnodeDef.h
index 3ad7de722e..5ffbd8dcff 100644
--- a/source/dnode/vnode/impl/inc/vnodeDef.h
+++ b/source/dnode/vnode/impl/inc/vnodeDef.h
@@ -19,6 +19,7 @@
 #include "mallocator.h"
 #include "sync.h"
 #include "tlockfree.h"
+#include "wal.h"
 
 #include "vnode.h"
 #include "vnodeAllocatorPool.h"
@@ -41,6 +42,7 @@ struct SVnode {
   SMeta*           pMeta;
   STsdb*           pTsdb;
   STQ*             pTq;
+  SWal*            pWal;
   SVnodeSync*      pSync;
   SVnodeFS*        pFs;
 };
diff --git a/source/dnode/vnode/impl/inc/vnodeMemAllocator.h b/source/dnode/vnode/impl/inc/vnodeMemAllocator.h
index 7e9bd21fe3..9184eb416b 100644
--- a/source/dnode/vnode/impl/inc/vnodeMemAllocator.h
+++ b/source/dnode/vnode/impl/inc/vnodeMemAllocator.h
@@ -16,10 +16,16 @@
 #ifndef _TD_VNODE_MEM_ALLOCATOR_H_
 #define _TD_VNODE_MEM_ALLOCATOR_H_
 
+#include "mallocator.h"
+#include "vnode.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+SMemAllocator *vnodeCreateMemAllocator(SVnode *pVnode);
+void           vnodeDestroyMemAllocator(SMemAllocator *pma);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/dnode/vnode/impl/src/vnodeMemAllocator.c b/source/dnode/vnode/impl/src/vnodeMemAllocator.c
index 3771a14113..902014eb47 100644
--- a/source/dnode/vnode/impl/src/vnodeMemAllocator.c
+++ b/source/dnode/vnode/impl/src/vnodeMemAllocator.c
@@ -15,6 +15,17 @@
 
 #include "vnodeDef.h"
 
+SMemAllocator *vnodeCreateMemAllocator(SVnode *pVnode) {
+  SMemAllocator *pma = NULL;
+  /* TODO */
+  return pma;
+}
+
+void vnodeDestroyMemAllocator(SMemAllocator *pma) {
+  // TODO
+}
+
+#if 0
 #define VNODE_HEAP_ALLOCATOR 0
 #define VNODE_ARENA_ALLOCATOR 1
 
@@ -97,4 +108,6 @@ void vnodeUnrefMemAllocator(SMemAllocator *pma) {
 
 /* ------------------------ Heap Allocator IMPL ------------------------ */
 
-/* ------------------------ Arena Allocator IMPL ------------------------ */
\ No newline at end of file
+/* ------------------------ Arena Allocator IMPL ------------------------ */
+
+#endif
\ No newline at end of file
diff --git a/source/dnode/vnode/tsdb/inc/tsdbDef.h b/source/dnode/vnode/tsdb/inc/tsdbDef.h
index ebe0d6b4b0..0a17387ba7 100644
--- a/source/dnode/vnode/tsdb/inc/tsdbDef.h
+++ b/source/dnode/vnode/tsdb/inc/tsdbDef.h
@@ -16,7 +16,10 @@
 #ifndef _TD_TSDB_DEF_H_
 #define _TD_TSDB_DEF_H_
 
+#include "mallocator.h"
+
 #include "tsdb.h"
+#include "tsdbMemTable.h"
 #include "tsdbOptions.h"
 
 #ifdef __cplusplus
@@ -24,8 +27,9 @@ extern "C" {
 #endif
 
 struct STsdb {
-  char *       path;
-  STsdbOptions options;
+  char *             path;
+  STsdbOptions       options;
+  STsdbMemAllocator *pTMA;
 };
 
 #ifdef __cplusplus
diff --git a/include/server/vnode/tsdb/impl/tsdbImpl.h b/source/dnode/vnode/tsdb/inc/tsdbMemTable.h
similarity index 81%
rename from include/server/vnode/tsdb/impl/tsdbImpl.h
rename to source/dnode/vnode/tsdb/inc/tsdbMemTable.h
index 04d2ec43c9..15d868de9f 100644
--- a/include/server/vnode/tsdb/impl/tsdbImpl.h
+++ b/source/dnode/vnode/tsdb/inc/tsdbMemTable.h
@@ -13,22 +13,17 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef _TD_TSDB_IMPL_H_
-#define _TD_TSDB_IMPL_H_
-
-#include "os.h"
+#ifndef _TD_TSDB_MEM_TABLE_H_
+#define _TD_TSDB_MEM_TABLE_H_
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-struct STsdbOptions {
-  size_t lruCacheSize;
-  /* TODO */
-};
+typedef struct SMemTable SMemTable;
 
 #ifdef __cplusplus
 }
 #endif
 
-#endif /*_TD_TSDB_IMPL_H_*/
\ No newline at end of file
+#endif /*_TD_TSDB_MEM_TABLE_H_*/
\ No newline at end of file
diff --git a/source/dnode/vnode/tsdb/src/tsdbMemTable.c b/source/dnode/vnode/tsdb/src/tsdbMemTable.c
new file mode 100644
index 0000000000..6dea4a4e57
--- /dev/null
+++ b/source/dnode/vnode/tsdb/src/tsdbMemTable.c
@@ -0,0 +1,14 @@
+/*
+ * 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/>.
+ */
\ No newline at end of file