diff --git a/src/vnode/cache/inc/cache.h b/src/vnode/cache/inc/cache.h
index 45b0e0c8007771dd4d0c27dd5a0e9c25026dc94e..c90c47a62183eb58ac77c502e430640dc16c8cb8 100644
--- a/src/vnode/cache/inc/cache.h
+++ b/src/vnode/cache/inc/cache.h
@@ -5,8 +5,9 @@ typedef void cache_pool_t;
 
 typedef struct SCacheBlock
 {
-
     SCacheBlock *next;
+    SCacheBlock *prev;
+    char data[];
 } SCacheBlock;
 
 
diff --git a/src/vnode/common/data/inc/data.h b/src/vnode/common/data/inc/data.h
index de9502e709e1efe19825aa5d1f1ba8c079567522..5ccecd4718b8ba6346ff8b7472b4732052146b20 100644
--- a/src/vnode/common/data/inc/data.h
+++ b/src/vnode/common/data/inc/data.h
@@ -3,16 +3,24 @@
 
 #include <stdint.h>
 
+/* The row data should in the form of
+ */
+
 // ---- Row data interface
 typedef struct {
-    int32_t numOfRows;
-    char * data;
+  int32_t numOfRows;
+  char *  data;
 } SRData;
 
 // ---- Column data interface
 typedef struct {
-    int32_t numOfPoints;
-    char *data;
+  int32_t numOfPoints;
+  char *  data;
 } SCData;
 
-#endif // _TD_DATA_H_
+typedef struct {
+  int32_t  numOfCols;
+  SCData **pData;
+} SCDataBlock;
+
+#endif  // _TD_DATA_H_
diff --git a/src/vnode/tsdb/inc/tsdbCache.h b/src/vnode/tsdb/inc/tsdbCache.h
new file mode 100644
index 0000000000000000000000000000000000000000..cafb545606f8a7bc1ef15cea1e28d25a05213af1
--- /dev/null
+++ b/src/vnode/tsdb/inc/tsdbCache.h
@@ -0,0 +1,14 @@
+#if !defined(_TD_TSDBCACHE_H_)
+#define _TD_TSDBCACHE_H_
+
+#include <stdint.h>
+
+#include "cache.h"
+
+typedef struct STSDBCache {
+    int64_t blockId;  // A block ID counter
+    SCacheBlock *blockList;
+} STSDBCache;
+
+
+#endif // _TD_TSDBCACHE_H_