diff --git a/src/tsdb/inc/tsdbMain.h b/src/tsdb/inc/tsdbMain.h
index 40c5ddbab5d22f4905683fec30108ce3b23e540e..25e8b9ce40af6785e6ecbdee32fbf94d57324d23 100644
--- a/src/tsdb/inc/tsdbMain.h
+++ b/src/tsdb/inc/tsdbMain.h
@@ -292,6 +292,9 @@ int           tsdbOpenBufPool(STsdbRepo* pRepo);
 SListNode*    tsdbAllocBufBlockFromPool(STsdbRepo* pRepo);
 
 // ------------------ tsdbMemTable.c
+int tsdbInsertRowToMem(STsdbRepo* pRepo, SDataRow row, STable* pTable);
+int tsdbRefMemTable(STsdbRepo* pRepo, SMemTable* pMemTable);
+int tsdbUnRefMemTable(STsdbRepo* pRepo, SMemTable* pMemTable);
 
 // ------------------ tsdbFile.c
 #define TSDB_KEY_FILEID(key, daysPerFile, precision) ((key) / tsMsPerDay[(precision)] / (daysPerFile))
diff --git a/src/tsdb/src/tsdbMemTable.c b/src/tsdb/src/tsdbMemTable.c
index ab8cccb293cb198c9b6cbd5d278d88fd26b2a764..074007af5ad48653d32c731f0aa68814702f5d45 100644
--- a/src/tsdb/src/tsdbMemTable.c
+++ b/src/tsdb/src/tsdbMemTable.c
@@ -18,6 +18,16 @@
 
 #define TSDB_DATA_SKIPLIST_LEVEL 5
 
+static FORCE_INLINE STsdbBufBlock *tsdbGetCurrBufBlock(STsdbRepo *pRepo);
+
+static void *      tsdbAllocBytes(STsdbRepo *pRepo, int bytes);
+static void        tsdbFreeBytes(STsdbRepo *pRepo, void *ptr, int bytes);
+static SMemTable * tsdbNewMemTable(STsdbCfg *pCfg);
+static void        tsdbFreeMemTable(SMemTable *pMemTable);
+static STableData *tsdbNewTableData(STsdbCfg *pCfg, STable *pTable);
+static void        tsdbFreeTableData(STableData *pTableData);
+static char *      tsdbGetTsTupleKey(const void *data);
+
 // ---------------- INTERNAL FUNCTIONS ----------------
 int tsdbInsertRowToMem(STsdbRepo *pRepo, SDataRow row, STable *pTable) {
   STsdbCfg *  pCfg = &pRepo->config;
@@ -104,7 +114,6 @@ int tsdbUnRefMemTable(STsdbRepo *pRepo, SMemTable *pMemTable) {
     STsdbBufPool *pBufPool = pRepo->pPool;
 
     SListNode *pNode = NULL;
-    // TODO: check the correctness of this code part
     if (tsdbLockRepo(pRepo) < 0) return -1;
     while ((pNode = tdListPopHead(pMemTable->bufBlockList)) != NULL) {
       tdListAppendNode(pBufPool->bufBlockList, pNode);