diff --git a/source/libs/tdb/src/db/pgcache.c b/source/libs/tdb/src/db/pgcache.c
index 1d7fe0c32f33e298844738412de5c1a398d2f746..b0c4406a3c509f058532846f8b50a2206caaa3d4 100644
--- a/source/libs/tdb/src/db/pgcache.c
+++ b/source/libs/tdb/src/db/pgcache.c
@@ -14,21 +14,6 @@
  */
 #include "tdbInt.h"
 
-typedef TD_DLIST(SPage) SPgList;
-
-struct SPgCache {
-  SRWLatch mutex;
-  pgsize_t pgsize;
-  int32_t  npage;
-  SPage *  pages;
-  SPgList  freeList;
-  SPgList  lru;
-  struct {
-    int32_t  nbucket;
-    SPgList *buckets;
-  } pght;  // page hash table
-};
-
 static void pgCachePinPage(SPage *pPage);
 static void pgCacheUnpinPage(SPage *pPage);
 
diff --git a/source/libs/tdb/src/db/tdbEnv.c b/source/libs/tdb/src/db/tdbEnv.c
index aae92f2bedaa57d44ab8f40128f630057924a008..7de52f36593e9a9a67d9e39eb7c1dcada5f1506d 100644
--- a/source/libs/tdb/src/db/tdbEnv.c
+++ b/source/libs/tdb/src/db/tdbEnv.c
@@ -18,4 +18,5 @@
 struct STDbEnv {
   TDB *    dbList;      // TDB list
   SPgFile *pgFileList;  // SPgFile list
+  SPgCache pgc;         // page cache
 };
\ No newline at end of file
diff --git a/source/libs/tdb/src/inc/pgcache.h b/source/libs/tdb/src/inc/pgcache.h
index d25877e8ffe14bc77cc5e4c1fcc7034c96be02e2..9296e0bea13be39eb3daa351e9e9a22aaf1844a9 100644
--- a/source/libs/tdb/src/inc/pgcache.h
+++ b/source/libs/tdb/src/inc/pgcache.h
@@ -44,6 +44,21 @@ struct SPage {
   uint8_t *   pData;     // real data
 };
 
+typedef TD_DLIST(SPage) SPgList;
+struct SPgCache {
+  TENV *   pEnv; // TENV containing this page cache
+  SRWLatch mutex;
+  pgsize_t pgsize;
+  int32_t  npage;
+  SPage *  pages;
+  SPgList  freeList;
+  SPgList  lru;
+  struct {
+    int32_t  nbucket;
+    SPgList *buckets;
+  } pght;  // page hash table
+};
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/tdb/src/inc/tdbEnv.h b/source/libs/tdb/src/inc/tdbEnv.h
new file mode 100644
index 0000000000000000000000000000000000000000..2bd93fc530d5ac2fd3a4ea1efc75192dc229cc38
--- /dev/null
+++ b/source/libs/tdb/src/inc/tdbEnv.h
@@ -0,0 +1,27 @@
+/*
+ * 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/>.
+ */
+
+#ifndef _TDB_ENV_H_
+#define _TDB_ENV_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /*_TDB_ENV_H_*/
\ No newline at end of file
diff --git a/source/libs/tdb/src/inc/tdbInt.h b/source/libs/tdb/src/inc/tdbInt.h
index a2bbcbd562927b6b77ec754d562573c1a50c43b8..cbab052049f8eb5151999803d4bffdb757fff112 100644
--- a/source/libs/tdb/src/inc/tdbInt.h
+++ b/source/libs/tdb/src/inc/tdbInt.h
@@ -79,6 +79,7 @@ typedef int32_t pgsize_t;
 #include "btree.h"
 #include "pgcache.h"
 #include "pgfile.h"
+#include "tdbEnv.h"
 
 // tdb util
 int tdbGnrtFileID(const char *fname, uint8_t *fileid);