diff --git a/src/mnode/inc/mgmtAcct.h b/src/mnode/inc/mgmtAcct.h
index 0c0bb8d05cd84bb9844947f5a27d50ae644170a7..136c28f2ae4b28deff2b8be938e4e76797f7c82b 100644
--- a/src/mnode/inc/mgmtAcct.h
+++ b/src/mnode/inc/mgmtAcct.h
@@ -25,7 +25,7 @@ extern "C" {
 int32_t mgmtInitAccts();
 void    mgmtCleanUpAccts();
 void *  mgmtGetAcct(char *acctName);
-void *  mgmtGetNextAcct(void *pNode, SAcctObj **pAcct);
+void *  mgmtGetNextAcct(void *pIter, SAcctObj **pAcct);
 void    mgmtIncAcctRef(SAcctObj *pAcct);
 void    mgmtDecAcctRef(SAcctObj *pAcct);
 void    mgmtAddDbToAcct(SAcctObj *pAcct, SDbObj *pDb);
diff --git a/src/mnode/inc/mgmtDb.h b/src/mnode/inc/mgmtDb.h
index b00a2bdf3de532755576fd308bf49877b9956b43..4ad46eee7baff5c57d8733584e027320eb5b8c84 100644
--- a/src/mnode/inc/mgmtDb.h
+++ b/src/mnode/inc/mgmtDb.h
@@ -32,7 +32,7 @@ int32_t mgmtInitDbs();
 void    mgmtCleanUpDbs();
 SDbObj *mgmtGetDb(char *db);
 SDbObj *mgmtGetDbByTableId(char *db);
-void *  mgmtGetNextDb(void *pNode, SDbObj **pDb);
+void *  mgmtGetNextDb(void *pIter, SDbObj **pDb);
 void    mgmtIncDbRef(SDbObj *pDb);
 void    mgmtDecDbRef(SDbObj *pDb);
 bool    mgmtCheckIsMonitorDB(char *db, char *monitordb);
diff --git a/src/mnode/inc/mgmtDef.h b/src/mnode/inc/mgmtDef.h
index 3ac2efb83b98f053d7f5fecb6885cb9ec516df28..f33531583a9e4891dae9e35ff0b76d755344bf2e 100644
--- a/src/mnode/inc/mgmtDef.h
+++ b/src/mnode/inc/mgmtDef.h
@@ -223,7 +223,7 @@ typedef struct SAcctObj {
 typedef struct {
   int8_t   type;
   char     db[TSDB_DB_NAME_LEN + 1];
-  void *   pNode;
+  void *   pIter;
   int16_t  numOfColumns;
   int32_t  rowSize;
   int32_t  numOfRows;
diff --git a/src/mnode/inc/mgmtDnode.h b/src/mnode/inc/mgmtDnode.h
index 1d7116c6c054977b41947f555708ddc377f032ba..c9e062255b017a06e4a53ff65ef7d8f2dcbd7479 100644
--- a/src/mnode/inc/mgmtDnode.h
+++ b/src/mnode/inc/mgmtDnode.h
@@ -34,7 +34,7 @@ char*   mgmtGetDnodeStatusStr(int32_t dnodeStatus);
 void    mgmtMonitorDnodeModule();
 
 int32_t mgmtGetDnodesNum();
-void *  mgmtGetNextDnode(void *pNode, SDnodeObj **pDnode);
+void *  mgmtGetNextDnode(void *pIter, SDnodeObj **pDnode);
 void    mgmtIncDnodeRef(SDnodeObj *pDnode);
 void    mgmtDecDnodeRef(SDnodeObj *pDnode);
 void *  mgmtGetDnode(int32_t dnodeId);
diff --git a/src/mnode/inc/mgmtMnode.h b/src/mnode/inc/mgmtMnode.h
index cb1d009c8c46962903316fb21b8f1c51fd032f76..b9a135346dc971205f97900149d6839f879a61cf 100644
--- a/src/mnode/inc/mgmtMnode.h
+++ b/src/mnode/inc/mgmtMnode.h
@@ -37,7 +37,7 @@ void    mgmtDropMnodeLocal(int32_t dnodeId);
 
 void *  mgmtGetMnode(int32_t mnodeId);
 int32_t mgmtGetMnodesNum();
-void *  mgmtGetNextMnode(void *pNode, struct SMnodeObj **pMnode);
+void *  mgmtGetNextMnode(void *pIter, struct SMnodeObj **pMnode);
 void    mgmtIncMnodeRef(struct SMnodeObj *pMnode);
 void    mgmtDecMnodeRef(struct SMnodeObj *pMnode);
 
diff --git a/src/mnode/inc/mgmtSdb.h b/src/mnode/inc/mgmtSdb.h
index 2b96eb4005aa3670b3b40a00d5a0f357457d3d0e..a97b1219a983b2d8dc722ea182446782a6de47d2 100644
--- a/src/mnode/inc/mgmtSdb.h
+++ b/src/mnode/inc/mgmtSdb.h
@@ -80,7 +80,8 @@ int32_t sdbDeleteRow(SSdbOper *pOper);
 int32_t sdbUpdateRow(SSdbOper *pOper);
 
 void    *sdbGetRow(void *handle, void *key);
-void    *sdbFetchRow(void *handle, void *pNode, void **ppRow);
+void    *sdbFetchRow(void *handle, void *pIter, void **ppRow);
+void     sdbFreeIter(void *pIter);
 void     sdbIncRef(void *thandle, void *pRow);
 void     sdbDecRef(void *thandle, void *pRow);
 int64_t  sdbGetNumOfRows(void *handle);
diff --git a/src/mnode/inc/mgmtTable.h b/src/mnode/inc/mgmtTable.h
index 9c4aa4a2a550bf0990cb5015716e6e91d9de4ea4..84220c9cf8ce942f86c668320e831beab2927fe0 100644
--- a/src/mnode/inc/mgmtTable.h
+++ b/src/mnode/inc/mgmtTable.h
@@ -27,8 +27,8 @@ void    mgmtCleanUpTables();
 void *  mgmtGetTable(char *tableId);
 void    mgmtIncTableRef(void *pTable);
 void    mgmtDecTableRef(void *pTable);
-void *  mgmtGetNextChildTable(void *pNode, SChildTableObj **pTable);
-void *  mgmtGetNextSuperTable(void *pNode, SSuperTableObj **pTable);
+void *  mgmtGetNextChildTable(void *pIter, SChildTableObj **pTable);
+void *  mgmtGetNextSuperTable(void *pIter, SSuperTableObj **pTable);
 void    mgmtDropAllChildTables(SDbObj *pDropDb);
 void    mgmtDropAllSuperTables(SDbObj *pDropDb);
 
diff --git a/src/mnode/inc/mgmtUser.h b/src/mnode/inc/mgmtUser.h
index 0a21b1f7044db6349466fff8d5cc5a1bf7a5b80a..2edd71f3e726fee724f168e0d1301261c33a530b 100644
--- a/src/mnode/inc/mgmtUser.h
+++ b/src/mnode/inc/mgmtUser.h
@@ -24,7 +24,7 @@ extern "C" {
 int32_t   mgmtInitUsers();
 void      mgmtCleanUpUsers();
 SUserObj *mgmtGetUser(char *name);
-void *    mgmtGetNextUser(void *pNode, SUserObj **pUser);
+void *    mgmtGetNextUser(void *pIter, SUserObj **pUser);
 void      mgmtIncUserRef(SUserObj *pUser);
 void      mgmtDecUserRef(SUserObj *pUser);
 SUserObj *mgmtGetUserFromConn(void *pConn);
diff --git a/src/mnode/inc/mgmtVgroup.h b/src/mnode/inc/mgmtVgroup.h
index 21a2c9b8963d2cb60d96ce8372bc1c0876a84ce0..7acf7112a4fe069e109d8e2d791b4b26520b9ac0 100644
--- a/src/mnode/inc/mgmtVgroup.h
+++ b/src/mnode/inc/mgmtVgroup.h
@@ -35,7 +35,7 @@ void    mgmtDecVgroupRef(SVgObj *pVgroup);
 void    mgmtDropAllDbVgroups(SDbObj *pDropDb, bool sendMsg);
 void    mgmtDropAllDnodeVgroups(SDnodeObj *pDropDnode);
 
-void *  mgmtGetNextVgroup(void *pNode, SVgObj **pVgroup);
+void *  mgmtGetNextVgroup(void *pIter, SVgObj **pVgroup);
 void    mgmtUpdateVgroup(SVgObj *pVgroup);
 void    mgmtUpdateVgroupStatus(SVgObj *pVgroup, SDnodeObj *dnodeId, SVnodeLoad *pVload);
 
diff --git a/src/mnode/src/mgmtAcct.c b/src/mnode/src/mgmtAcct.c
index 1cacec96eee5d724109daa5428afdc0a20b03b5d..27beff8944f717d4193fdd6ae91b5a2c23c84506 100644
--- a/src/mnode/src/mgmtAcct.c
+++ b/src/mnode/src/mgmtAcct.c
@@ -126,8 +126,8 @@ void *mgmtGetAcct(char *name) {
   return sdbGetRow(tsAcctSdb, name);
 }
 
-void *mgmtGetNextAcct(void *pNode, SAcctObj **pAcct) {
-  return sdbFetchRow(tsAcctSdb, pNode, (void **)pAcct); 
+void *mgmtGetNextAcct(void *pIter, SAcctObj **pAcct) {
+  return sdbFetchRow(tsAcctSdb, pIter, (void **)pAcct); 
 }
 
 void mgmtIncAcctRef(SAcctObj *pAcct) {
diff --git a/src/mnode/src/mgmtBalance.c b/src/mnode/src/mgmtBalance.c
index ff5b4008bbcbef3a8620e0ec95e2dc6ae991f7f6..f8410a207ef34db7d6ad8f12557d220aba630968 100644
--- a/src/mnode/src/mgmtBalance.c
+++ b/src/mnode/src/mgmtBalance.c
@@ -22,6 +22,7 @@
 #include "mgmtInt.h"
 #include "mgmtMnode.h"
 #include "mgmtDnode.h"
+#include "mgmtSdb.h"
 #include "mgmtVgroup.h"
 
 #ifndef _SYNC
@@ -33,13 +34,13 @@ void    balanceUpdateMgmt() {}
 void    balanceReset() {}
 
 int32_t balanceAllocVnodes(SVgObj *pVgroup) {
-  void *     pNode = NULL;
+  void *     pIter = NULL;
   SDnodeObj *pDnode = NULL;
   SDnodeObj *pSelDnode = NULL;
   float      vnodeUsage = 1000.0;
 
   while (1) {
-    pNode = mgmtGetNextDnode(pNode, &pDnode);
+    pIter = mgmtGetNextDnode(pIter, &pDnode);
     if (pDnode == NULL) break;
 
     if (pDnode->totalVnodes > 0 && pDnode->openVnodes < pDnode->totalVnodes) {
@@ -55,6 +56,8 @@ int32_t balanceAllocVnodes(SVgObj *pVgroup) {
     mgmtDecDnodeRef(pDnode);
   }
 
+  sdbFreeIter(pIter);
+
   if (pSelDnode == NULL) {
     mError("failed to alloc vnode to vgroup");
     return TSDB_CODE_NO_ENOUGH_DNODES;
diff --git a/src/mnode/src/mgmtDb.c b/src/mnode/src/mgmtDb.c
index 2f17df92fa70a218b666a18557ceb4f8fc15e737..3f43d4bf8911c9ad8e92c76b788bfcf19d03752d 100644
--- a/src/mnode/src/mgmtDb.c
+++ b/src/mnode/src/mgmtDb.c
@@ -156,8 +156,8 @@ int32_t mgmtInitDbs() {
   return 0;
 }
 
-void *mgmtGetNextDb(void *pNode, SDbObj **pDb) {
-  return sdbFetchRow(tsDbSdb, pNode, (void **)pDb);
+void *mgmtGetNextDb(void *pIter, SDbObj **pDb) {
+  return sdbFetchRow(tsDbSdb, pIter, (void **)pDb);
 }
 
 SDbObj *mgmtGetDb(char *db) {
@@ -583,7 +583,7 @@ static int32_t mgmtRetrieveDbs(SShowObj *pShow, char *data, int32_t rows, void *
   if (pUser == NULL) return 0;
 
   while (numOfRows < rows) {
-    pShow->pNode = mgmtGetNextDb(pShow->pNode, &pDb);
+    pShow->pIter = mgmtGetNextDb(pShow->pIter, &pDb);
     if (pDb == NULL) break;
 
     cols = 0;
@@ -865,14 +865,15 @@ static int32_t mgmtAlterDb(SDbObj *pDb, SCMAlterDbMsg *pAlter) {
     }
   }
 
-  void *pNode = NULL;
+  void *pIter = NULL;
   while (1) {
     SVgObj *pVgroup = NULL;
-    pNode = mgmtGetNextVgroup(pNode, &pVgroup);
+    pIter = mgmtGetNextVgroup(pIter, &pVgroup);
     if (pVgroup == NULL) break;   
     mgmtSendCreateVgroupMsg(pVgroup, NULL);
     mgmtDecVgroupRef(pVgroup);
   }
+  sdbFreeIter(pIter);
 
   if (oldReplica != pDb->cfg.replications) {
     balanceNotify();
@@ -983,12 +984,12 @@ static void mgmtProcessDropDbMsg(SQueuedMsg *pMsg) {
 void  mgmtDropAllDbs(SAcctObj *pAcct)  {
   int32_t numOfDbs = 0;
   SDbObj *pDb = NULL;
-  void *  pNode = NULL;
+  void *  pIter = NULL;
 
   mPrint("acct:%s, all dbs will be dropped from sdb", pAcct->user);
 
   while (1) {
-    pNode = mgmtGetNextDb(pNode, &pDb);
+    pIter = mgmtGetNextDb(pIter, &pDb);
     if (pDb == NULL) break;
 
     if (pDb->pAcct == pAcct) {
@@ -1005,5 +1006,7 @@ void  mgmtDropAllDbs(SAcctObj *pAcct)  {
     mgmtDecDbRef(pDb);
   }
 
+  sdbFreeIter(pIter);
+
   mPrint("acct:%s, all dbs:%d is dropped from sdb", pAcct->user, numOfDbs);
 }
diff --git a/src/mnode/src/mgmtDnode.c b/src/mnode/src/mgmtDnode.c
index d60dae32aef9a9762378121d99ec36cf11aa6bf5..463f5dde478c8e126a579d8db6540c24deca5786 100644
--- a/src/mnode/src/mgmtDnode.c
+++ b/src/mnode/src/mgmtDnode.c
@@ -170,8 +170,8 @@ void mgmtCleanupDnodes() {
   sdbCloseTable(tsDnodeSdb);
 }
 
-void *mgmtGetNextDnode(void *pNode, SDnodeObj **pDnode) { 
-  return sdbFetchRow(tsDnodeSdb, pNode, (void **)pDnode); 
+void *mgmtGetNextDnode(void *pIter, SDnodeObj **pDnode) { 
+  return sdbFetchRow(tsDnodeSdb, pIter, (void **)pDnode); 
 }
 
 int32_t mgmtGetDnodesNum() {
@@ -184,17 +184,20 @@ void *mgmtGetDnode(int32_t dnodeId) {
 
 void *mgmtGetDnodeByEp(char *ep) {
   SDnodeObj *pDnode = NULL;
-  void *     pNode = NULL;
+  void *     pIter = NULL;
 
   while (1) {
-    pNode = mgmtGetNextDnode(pNode, &pDnode);
+    pIter = mgmtGetNextDnode(pIter, &pDnode);
     if (pDnode == NULL) break;
     if (strcmp(ep, pDnode->dnodeEp) == 0) {
+      sdbFreeIter(pIter);
       return pDnode;
     }
     mgmtDecDnodeRef(pDnode);
   }
 
+  sdbFreeIter(pIter);
+
   return NULL;
 }
 
@@ -530,7 +533,7 @@ static int32_t mgmtGetDnodeMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pCo
 
   pShow->numOfRows = mgmtGetDnodesNum();
   pShow->rowSize = pShow->offset[cols - 1] + pShow->bytes[cols - 1];
-  pShow->pNode = NULL;
+  pShow->pIter = NULL;
 
   mgmtDecUserRef(pUser);
 
@@ -544,7 +547,7 @@ static int32_t mgmtRetrieveDnodes(SShowObj *pShow, char *data, int32_t rows, voi
   char      *pWrite;
 
   while (numOfRows < rows) {
-    pShow->pNode = mgmtGetNextDnode(pShow->pNode, &pDnode);
+    pShow->pIter = mgmtGetNextDnode(pShow->pIter, &pDnode);
     if (pDnode == NULL) break;
 
     cols = 0;
@@ -636,7 +639,7 @@ static int32_t mgmtGetModuleMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pC
 
   pShow->numOfRows = mgmtGetDnodesNum() * TSDB_MOD_MAX;
   pShow->rowSize = pShow->offset[cols - 1] + pShow->bytes[cols - 1];
-  pShow->pNode = NULL;
+  pShow->pIter = NULL;
   mgmtDecUserRef(pUser);
 
   return 0;
@@ -648,7 +651,7 @@ int32_t mgmtRetrieveModules(SShowObj *pShow, char *data, int32_t rows, void *pCo
 
   while (numOfRows < rows) {
     SDnodeObj *pDnode = NULL;
-    pShow->pNode = mgmtGetNextDnode(pShow->pNode, (SDnodeObj **)&pDnode);
+    pShow->pIter = mgmtGetNextDnode(pShow->pIter, (SDnodeObj **)&pDnode);
     if (pDnode == NULL) break;
 
     for (int32_t moduleType = 0; moduleType < TSDB_MOD_MAX; ++moduleType) {
@@ -738,7 +741,7 @@ static int32_t mgmtGetConfigMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pC
   }
 
   pShow->rowSize = pShow->offset[cols - 1] + pShow->bytes[cols - 1];
-  pShow->pNode = NULL;
+  pShow->pIter = NULL;
   mgmtDecUserRef(pUser);
 
   return 0;
@@ -821,7 +824,8 @@ static int32_t mgmtGetVnodeMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pCo
   if (pShow->payloadLen > 0 ) {
     pDnode = mgmtGetDnodeByEp(pShow->payload);
   } else {
-    mgmtGetNextDnode(NULL, (SDnodeObj **)&pDnode);
+    void *pIter = mgmtGetNextDnode(NULL, (SDnodeObj **)&pDnode);
+    sdbFreeIter(pIter);
   }
 
   if (pDnode != NULL) {
@@ -830,7 +834,7 @@ static int32_t mgmtGetVnodeMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pCo
   }
 
   pShow->rowSize = pShow->offset[cols - 1] + pShow->bytes[cols - 1];
-  pShow->pNode = pDnode;
+  pShow->pIter = pDnode;
   mgmtDecUserRef(pUser);
 
   return 0;
@@ -844,12 +848,12 @@ static int32_t mgmtRetrieveVnodes(SShowObj *pShow, char *data, int32_t rows, voi
 
   if (0 == rows) return 0;
 
-  pDnode = (SDnodeObj *)(pShow->pNode);
+  pDnode = (SDnodeObj *)(pShow->pIter);
   if (pDnode != NULL) {
-    void *pNode = NULL;
+    void *pIter = NULL;
     SVgObj *pVgroup;
     while (1) {
-      pNode = mgmtGetNextVgroup(pNode, &pVgroup);
+      pIter = mgmtGetNextVgroup(pIter, &pVgroup);
       if (pVgroup == NULL) break;
 
       for (int32_t i = 0; i < pVgroup->numOfVnodes; ++i) {
@@ -869,6 +873,7 @@ static int32_t mgmtRetrieveVnodes(SShowObj *pShow, char *data, int32_t rows, voi
 
       mgmtDecVgroupRef(pVgroup);
     }
+    sdbFreeIter(pIter);
   } else {
     numOfRows = 0;
   }
diff --git a/src/mnode/src/mgmtMnode.c b/src/mnode/src/mgmtMnode.c
index a78e5574c065b5a1b05d94cbff364a70662164e4..d9ddd465f6d7ac1e60db572e2839905a498bac03 100644
--- a/src/mnode/src/mgmtMnode.c
+++ b/src/mnode/src/mgmtMnode.c
@@ -95,11 +95,12 @@ static int32_t mgmtMnodeActionDecode(SSdbOper *pOper) {
 static int32_t mgmtMnodeActionRestored() {
   if (mgmtGetMnodesNum() == 1) {
     SMnodeObj *pMnode = NULL;
-    mgmtGetNextMnode(NULL, &pMnode);
+    void *pIter = mgmtGetNextMnode(NULL, &pMnode);
     if (pMnode != NULL) {
       pMnode->role = TAOS_SYNC_ROLE_MASTER;
       mgmtDecMnodeRef(pMnode);
     }
+    sdbFreeIter(pIter);
   }
   return TSDB_CODE_SUCCESS;
 }
@@ -157,8 +158,8 @@ void mgmtDecMnodeRef(SMnodeObj *pMnode) {
   sdbDecRef(tsMnodeSdb, pMnode);
 }
 
-void *mgmtGetNextMnode(void *pNode, SMnodeObj **pMnode) { 
-  return sdbFetchRow(tsMnodeSdb, pNode, (void **)pMnode); 
+void *mgmtGetNextMnode(void *pIter, SMnodeObj **pMnode) { 
+  return sdbFetchRow(tsMnodeSdb, pIter, (void **)pMnode); 
 }
 
 char *mgmtGetMnodeRoleStr(int32_t role) {
@@ -177,10 +178,10 @@ char *mgmtGetMnodeRoleStr(int32_t role) {
 }
 
 void mgmtGetMnodeIpSet(SRpcIpSet *ipSet) {
-  void *pNode = NULL;
+  void *pIter = NULL;
   while (1) {
     SMnodeObj *pMnode = NULL;
-    pNode = mgmtGetNextMnode(pNode, &pMnode);
+    pIter = mgmtGetNextMnode(pIter, &pMnode);
     if (pMnode == NULL) break;
 
     strcpy(ipSet->fqdn[ipSet->numOfIps], pMnode->pDnode->dnodeFqdn);
@@ -194,6 +195,7 @@ void mgmtGetMnodeIpSet(SRpcIpSet *ipSet) {
     
     mgmtDecMnodeRef(pMnode);
   }
+  sdbFreeIter(pIter);
 }
 
 void mgmtGetMnodeInfos(void *param) {
@@ -201,10 +203,10 @@ void mgmtGetMnodeInfos(void *param) {
   mnodes->inUse = 0;
   
   int32_t index = 0;
-  void *pNode = NULL;
+  void *pIter = NULL;
   while (1) {
     SMnodeObj *pMnode = NULL;
-    pNode = mgmtGetNextMnode(pNode, &pMnode);
+    pIter = mgmtGetNextMnode(pIter, &pMnode);
     if (pMnode == NULL) break;
 
     mnodes->nodeInfos[index].nodeId = htonl(pMnode->mnodeId);
@@ -216,6 +218,7 @@ void mgmtGetMnodeInfos(void *param) {
     index++;
     mgmtDecMnodeRef(pMnode);
   }
+  sdbFreeIter(pIter);
 
   mnodes->nodeNum = index;
 }
@@ -317,7 +320,7 @@ static int32_t mgmtGetMnodeMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pCo
 
   pShow->numOfRows = mgmtGetMnodesNum();
   pShow->rowSize = pShow->offset[cols - 1] + pShow->bytes[cols - 1];
-  pShow->pNode = NULL;
+  pShow->pIter = NULL;
   mgmtDecUserRef(pUser);
 
   return 0;
@@ -330,7 +333,7 @@ static int32_t mgmtRetrieveMnodes(SShowObj *pShow, char *data, int32_t rows, voi
   char      *pWrite;
 
   while (numOfRows < rows) {
-    pShow->pNode = mgmtGetNextMnode(pShow->pNode, &pMnode);
+    pShow->pIter = mgmtGetNextMnode(pShow->pIter, &pMnode);
     if (pMnode == NULL) break;
 
     cols = 0;
diff --git a/src/mnode/src/mgmtProfile.c b/src/mnode/src/mgmtProfile.c
index 64ac8ed71058e6ef269d337585bfb7c4a8044a2c..6667bff0524e9cc1ce340ff2337d49c2a3613104 100644
--- a/src/mnode/src/mgmtProfile.c
+++ b/src/mnode/src/mgmtProfile.c
@@ -140,7 +140,7 @@ int32_t mgmtGetQueries(SShowObj *pShow, void *pConn) {
 //
 //  // sorting based on useconds
 //
-//  pShow->pNode = pQueryShow;
+//  pShow->pIter = pQueryShow;
 
   return 0;
 }
@@ -187,7 +187,7 @@ int32_t mgmtGetQueryMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pConn) {
   for (int32_t i = 1; i < cols; ++i) pShow->offset[i] = pShow->offset[i - 1] + pShow->bytes[i - 1];
 
   pShow->numOfRows = 1000000;
-  pShow->pNode = NULL;
+  pShow->pIter = NULL;
   pShow->rowSize = pShow->offset[cols - 1] + pShow->bytes[cols - 1];
 
   mgmtGetQueries(pShow, pConn);
@@ -252,7 +252,7 @@ int32_t mgmtRetrieveQueries(SShowObj *pShow, char *data, int32_t rows, void *pCo
   char *pWrite;
   int32_t   cols = 0;
 
-  SQueryShow *pQueryShow = (SQueryShow *)pShow->pNode;
+  SQueryShow *pQueryShow = (SQueryShow *)pShow->pIter;
 
   if (rows > pQueryShow->numOfQueries - pQueryShow->index) rows = pQueryShow->numOfQueries - pQueryShow->index;
 
@@ -339,7 +339,7 @@ int32_t mgmtGetStreams(SShowObj *pShow, void *pConn) {
 //
 //  // sorting based on useconds
 //
-//  pShow->pNode = pStreamShow;
+//  pShow->pIter = pStreamShow;
 
   return 0;
 }
@@ -397,7 +397,7 @@ int32_t mgmtGetStreamMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pConn) {
   for (int32_t i = 1; i < cols; ++i) pShow->offset[i] = pShow->offset[i - 1] + pShow->bytes[i - 1];
 
   pShow->numOfRows = 1000000;
-  pShow->pNode = NULL;
+  pShow->pIter = NULL;
   pShow->rowSize = pShow->offset[cols - 1] + pShow->bytes[cols - 1];
 
   mgmtGetStreams(pShow, pConn);
@@ -409,7 +409,7 @@ int32_t mgmtRetrieveStreams(SShowObj *pShow, char *data, int32_t rows, void *pCo
   char *pWrite;
   int32_t   cols = 0;
 
-  SStreamShow *pStreamShow = (SStreamShow *)pShow->pNode;
+  SStreamShow *pStreamShow = (SStreamShow *)pShow->pIter;
 
   if (rows > pStreamShow->numOfStreams - pStreamShow->index) rows = pStreamShow->numOfStreams - pStreamShow->index;
 
@@ -592,7 +592,7 @@ int mgmtGetConns(SShowObj *pShow, void *pConn) {
   //
   //  // sorting based on useconds
   //
-  //  pShow->pNode = pConnShow;
+  //  pShow->pIter = pConnShow;
 
   return 0;
 }
@@ -627,7 +627,7 @@ int32_t mgmtGetConnsMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pConn) {
   for (int i = 1; i < cols; ++i) pShow->offset[i] = pShow->offset[i - 1] + pShow->bytes[i - 1];
 
   pShow->numOfRows = 1000000;
-  pShow->pNode = NULL;
+  pShow->pIter = NULL;
   pShow->rowSize = pShow->offset[cols - 1] + pShow->bytes[cols - 1];
 
   mgmtGetConns(pShow, pConn);
@@ -639,7 +639,7 @@ int32_t mgmtRetrieveConns(SShowObj *pShow, char *data, int32_t rows, void *pConn
   char      *pWrite;
   int32_t   cols = 0;
 
-  SConnShow *pConnShow = (SConnShow *)pShow->pNode;
+  SConnShow *pConnShow = (SConnShow *)pShow->pIter;
 
   if (rows > pConnShow->numOfConns - pConnShow->index) rows = pConnShow->numOfConns - pConnShow->index;
 
diff --git a/src/mnode/src/mgmtSdb.c b/src/mnode/src/mgmtSdb.c
index 3116ad39f344fff43998d8b16770cc709d85c8bc..3a9ef390f99ad87bb8777951a43dd5f29df901c8 100644
--- a/src/mnode/src/mgmtSdb.c
+++ b/src/mnode/src/mgmtSdb.c
@@ -239,10 +239,10 @@ void sdbUpdateSync() {
   }
 
   if (index == 0) {
-    void *pNode = NULL;
+    void *pIter = NULL;
     while (1) {
       SMnodeObj *pMnode = NULL;
-      pNode = mgmtGetNextMnode(pNode, &pMnode);
+      pIter = mgmtGetNextMnode(pIter, &pMnode);
       if (pMnode == NULL) break;
 
       syncCfg.nodeInfo[index].nodeId = pMnode->mnodeId;
@@ -252,6 +252,7 @@ void sdbUpdateSync() {
 
       mgmtDecMnodeRef(pMnode);
     }
+    sdbFreeIter(pIter);
   }
 
   syncCfg.replica = index;
@@ -666,7 +667,10 @@ void *sdbFetchRow(void *handle, void *pNode, void **ppRow) {
   }
 
   SSdbRow *pMeta = taosHashIterGet(pIter);
-  if (pMeta == NULL) return NULL;
+  if (pMeta == NULL) {
+    taosHashDestroyIter(pIter);
+    return NULL;
+  }
 
   *ppRow = pMeta->row;
   sdbIncRef(handle, pMeta->row);
@@ -674,6 +678,12 @@ void *sdbFetchRow(void *handle, void *pNode, void **ppRow) {
   return pIter;
 }
 
+void sdbFreeIter(void *pIter) {
+  if (pIter != NULL) {
+    taosHashDestroyIter(pIter);
+  }
+}
+
 void *sdbOpenTable(SSdbTableDesc *pDesc) {
   SSdbTable *pTable = (SSdbTable *)calloc(1, sizeof(SSdbTable));
   
diff --git a/src/mnode/src/mgmtShell.c b/src/mnode/src/mgmtShell.c
index c27dc66dd5004384be539931d67b280a651d7e86..2e3ef7384aba3cb5df83655996cd2424c866a73b 100644
--- a/src/mnode/src/mgmtShell.c
+++ b/src/mnode/src/mgmtShell.c
@@ -48,6 +48,7 @@ static void mgmtProcessRetrieveMsg(SQueuedMsg *queuedMsg);
 static void mgmtProcessHeartBeatMsg(SQueuedMsg *queuedMsg);
 static void mgmtProcessConnectMsg(SQueuedMsg *queuedMsg);
 static void mgmtProcessUseMsg(SQueuedMsg *queuedMsg);
+static void mgmtFreeShowObj(void *data);
 
 void *tsMgmtTmr;
 static void *tsMgmtTranQhandle = NULL;
@@ -65,7 +66,7 @@ int32_t mgmtInitShell() {
   
   tsMgmtTmr = taosTmrInit((tsMaxShellConns) * 3, 200, 3600000, "MND");
   tsMgmtTranQhandle = taosInitScheduler(tsMaxShellConns, 1, "mnodeT");
-  tsQhandleCache = taosCacheInit(tsMgmtTmr, 10);
+  tsQhandleCache = taosCacheInitWithCb(tsMgmtTmr, 10, mgmtFreeShowObj);
 
   return 0;
 }
@@ -479,7 +480,7 @@ bool mgmtCheckQhandle(uint64_t qhandle) {
     mTrace("qhandle:%p is retrived", qhandle);
     return true;
   } else {
-    mTrace("qhandle:%p is already freed", qhandle);
+    mTrace("qhandle:%p is already released", qhandle);
     return false;
   }
 }
@@ -498,8 +499,14 @@ void* mgmtSaveQhandle(void *qhandle, int32_t size) {
   return NULL;
 }
 
+static void mgmtFreeShowObj(void *data) {
+  SShowObj *pShow = data;
+  //sdbFreeIter(pShow->pIter);
+  mTrace("qhandle:%p is destroyed", pShow);
+}
+
 void mgmtFreeQhandle(void *qhandle, bool forceRemove) {
-  mTrace("qhandle:%p is freed", qhandle);
+  mTrace("qhandle:%p is released", qhandle);
   taosCacheRelease(tsQhandleCache, &qhandle, forceRemove);
 }
 
diff --git a/src/mnode/src/mgmtTable.c b/src/mnode/src/mgmtTable.c
index affd7a1073669bf5dceb376bb3403a389582992a..ae2c4c1f6c56e31850681f123a4f427793999ffa 100644
--- a/src/mnode/src/mgmtTable.c
+++ b/src/mnode/src/mgmtTable.c
@@ -247,25 +247,19 @@ static int32_t mgmtChildTableActionDecode(SSdbOper *pOper) {
 }
 
 static int32_t mgmtChildTableActionRestored() {
-  void *pNode = NULL;
-  void *pLastNode = NULL;
+  void *pIter = NULL;
   SChildTableObj *pTable = NULL;
 
   while (1) {
-    pLastNode = pNode;
     mgmtDecTableRef(pTable);
-    pNode = mgmtGetNextChildTable(pNode, &pTable);
+    pIter = mgmtGetNextChildTable(pIter, &pTable);
     if (pTable == NULL) break;
 
     SDbObj *pDb = mgmtGetDbByTableId(pTable->info.tableId);
     if (pDb == NULL) {
       mError("ctable:%s, failed to get db, discard it", pTable->info.tableId);
-      SSdbOper desc = {0};
-      desc.type = SDB_OPER_LOCAL;
-      desc.pObj = pTable;
-      desc.table = tsChildTableSdb;
+      SSdbOper desc = {.type = SDB_OPER_LOCAL, .pObj = pTable, .table = tsChildTableSdb};
       sdbDeleteRow(&desc);
-      pNode = pLastNode;
       continue;
     }
     mgmtDecDbRef(pDb);
@@ -274,12 +268,8 @@ static int32_t mgmtChildTableActionRestored() {
     if (pVgroup == NULL) {
       mError("ctable:%s, failed to get vgId:%d sid:%d, discard it", pTable->info.tableId, pTable->vgId, pTable->sid);
       pTable->vgId = 0;
-      SSdbOper desc = {0};
-      desc.type = SDB_OPER_LOCAL;
-      desc.pObj = pTable;
-      desc.table = tsChildTableSdb;
+      SSdbOper desc = {.type = SDB_OPER_LOCAL, .pObj = pTable, .table = tsChildTableSdb};
       sdbDeleteRow(&desc);
-      pNode = pLastNode;
       continue;
     }
     mgmtDecVgroupRef(pVgroup);
@@ -288,24 +278,16 @@ static int32_t mgmtChildTableActionRestored() {
       mError("ctable:%s, db:%s not match with vgId:%d db:%s sid:%d, discard it",
              pTable->info.tableId, pDb->name, pTable->vgId, pVgroup->dbName, pTable->sid);
       pTable->vgId = 0;
-      SSdbOper desc = {0};
-      desc.type = SDB_OPER_LOCAL;
-      desc.pObj = pTable;
-      desc.table = tsChildTableSdb;
+      SSdbOper desc = {.type = SDB_OPER_LOCAL, .pObj = pTable, .table = tsChildTableSdb};
       sdbDeleteRow(&desc);
-      pNode = pLastNode;
       continue;
     }
 
     if (pVgroup->tableList == NULL) {
       mError("ctable:%s, vgId:%d tableList is null", pTable->info.tableId, pTable->vgId);
       pTable->vgId = 0;
-      SSdbOper desc = {0};
-      desc.type = SDB_OPER_LOCAL;
-      desc.pObj = pTable;
-      desc.table = tsChildTableSdb;
+      SSdbOper desc = {.type = SDB_OPER_LOCAL, .pObj = pTable, .table = tsChildTableSdb};
       sdbDeleteRow(&desc);
-      pNode = pLastNode;
       continue;
     }
 
@@ -314,18 +296,16 @@ static int32_t mgmtChildTableActionRestored() {
       if (pSuperTable == NULL) {
         mError("ctable:%s, stable:%" PRIu64 " not exist", pTable->info.tableId, pTable->suid);
         pTable->vgId = 0;
-        SSdbOper desc = {0};
-        desc.type = SDB_OPER_LOCAL;
-        desc.pObj = pTable;
-        desc.table = tsChildTableSdb;
+        SSdbOper desc = {.type = SDB_OPER_LOCAL, .pObj = pTable, .table = tsChildTableSdb};
         sdbDeleteRow(&desc);
-        pNode = pLastNode;
         continue;
       }
       mgmtDecTableRef(pSuperTable);
     }
   }
 
+  sdbFreeIter(pIter);
+
   return 0;
 }
 
@@ -560,10 +540,10 @@ static void *mgmtGetSuperTable(char *tableId) {
 
 static void *mgmtGetSuperTableByUid(uint64_t uid) {
   SSuperTableObj *pStable = NULL;
-  void *          pNode = NULL;
+  void *pIter = NULL;
 
   while (1) {
-    pNode = mgmtGetNextSuperTable(pNode, &pStable);
+    pIter = mgmtGetNextSuperTable(pIter, &pStable);
     if (pStable == NULL) break;
     if (pStable->uid == uid) {
       return pStable;
@@ -571,6 +551,8 @@ static void *mgmtGetSuperTableByUid(uint64_t uid) {
     mgmtDecTableRef(pStable);
   }
 
+  sdbFreeIter(pIter);
+
   return NULL;
 }
 
@@ -588,12 +570,12 @@ void *mgmtGetTable(char *tableId) {
   return NULL;
 }
 
-void *mgmtGetNextChildTable(void *pNode, SChildTableObj **pTable) {
-  return sdbFetchRow(tsChildTableSdb, pNode, (void **)pTable);
+void *mgmtGetNextChildTable(void *pIter, SChildTableObj **pTable) {
+  return sdbFetchRow(tsChildTableSdb, pIter, (void **)pTable);
 }
 
-void *mgmtGetNextSuperTable(void *pNode, SSuperTableObj **pTable) {
-  return sdbFetchRow(tsSuperTableSdb, pNode, (void **)pTable);
+void *mgmtGetNextSuperTable(void *pIter, SSuperTableObj **pTable) {
+  return sdbFetchRow(tsSuperTableSdb, pIter, (void **)pTable);
 }
 
 void mgmtIncTableRef(void *p1) {
@@ -1122,7 +1104,7 @@ int32_t mgmtRetrieveShowSuperTables(SShowObj *pShow, char *data, int32_t rows, v
 
   while (numOfRows < rows) {    
     mgmtDecTableRef(pTable);
-    pShow->pNode = mgmtGetNextSuperTable(pShow->pNode, &pTable);
+    pShow->pIter = mgmtGetNextSuperTable(pShow->pIter, &pTable);
     if (pTable == NULL) break;
     if (strncmp(pTable->info.tableId, prefix, prefixLen)) {
       continue;
@@ -1172,8 +1154,7 @@ int32_t mgmtRetrieveShowSuperTables(SShowObj *pShow, char *data, int32_t rows, v
 }
 
 void mgmtDropAllSuperTables(SDbObj *pDropDb) {
-  void *pNode = NULL;
-  void *pLastNode = NULL;
+  void *  pIter= NULL;
   int32_t numOfTables = 0;
   int32_t dbNameLen = strlen(pDropDb->name);
   SSuperTableObj *pTable = NULL;
@@ -1181,8 +1162,7 @@ void mgmtDropAllSuperTables(SDbObj *pDropDb) {
   mPrint("db:%s, all super tables will be dropped from sdb", pDropDb->name);
 
   while (1) {
-    pLastNode = pNode;
-    pNode = mgmtGetNextSuperTable(pNode, &pTable);
+    pIter = mgmtGetNextSuperTable(pIter, &pTable);
     if (pTable == NULL) break;
 
     if (strncmp(pDropDb->name, pTable->info.tableId, dbNameLen) == 0) {
@@ -1192,13 +1172,14 @@ void mgmtDropAllSuperTables(SDbObj *pDropDb) {
         .pObj = pTable,
       };
       sdbDeleteRow(&oper);
-      pNode = pLastNode;
       numOfTables ++;
     }
 
     mgmtDecTableRef(pTable);
   }
 
+  sdbFreeIter(pIter);
+
   mPrint("db:%s, all super tables:%d is dropped from sdb", pDropDb->name, numOfTables);
 }
 
@@ -1753,8 +1734,7 @@ static void mgmtGetChildTableMeta(SQueuedMsg *pMsg) {
 }
 
 void mgmtDropAllChildTables(SDbObj *pDropDb) {
-  void *pNode = NULL;
-  void *pLastNode = NULL;
+  void *  pIter = NULL;
   int32_t numOfTables = 0;
   int32_t dbNameLen = strlen(pDropDb->name);
   SChildTableObj *pTable = NULL;
@@ -1762,8 +1742,7 @@ void mgmtDropAllChildTables(SDbObj *pDropDb) {
   mPrint("db:%s, all child tables will be dropped from sdb", pDropDb->name);
 
   while (1) {
-    pLastNode = pNode;
-    pNode = mgmtGetNextChildTable(pNode, &pTable);
+    pIter = mgmtGetNextChildTable(pIter, &pTable);
     if (pTable == NULL) break;
 
     if (strncmp(pDropDb->name, pTable->info.tableId, dbNameLen) == 0) {
@@ -1773,26 +1752,25 @@ void mgmtDropAllChildTables(SDbObj *pDropDb) {
         .pObj = pTable,
       };
       sdbDeleteRow(&oper);
-      pNode = pLastNode;
       numOfTables++;
     }
     mgmtDecTableRef(pTable);
   }
 
+  sdbFreeIter(pIter);
+
   mPrint("db:%s, all child tables:%d is dropped from sdb", pDropDb->name, numOfTables);
 }
 
 static void mgmtDropAllChildTablesInStable(SSuperTableObj *pStable) {
-  void *pNode = NULL;
-  void *pLastNode = NULL;
+  void *  pIter = NULL;
   int32_t numOfTables = 0;
   SChildTableObj *pTable = NULL;
 
   mPrint("stable:%s, all child tables will dropped from sdb", pStable->info.tableId, numOfTables);
 
   while (1) {
-    pLastNode = pNode;
-    pNode = mgmtGetNextChildTable(pNode, &pTable);
+    pIter = mgmtGetNextChildTable(pIter, &pTable);
     if (pTable == NULL) break;
 
     if (pTable->superTable == pStable) {
@@ -1802,13 +1780,14 @@ static void mgmtDropAllChildTablesInStable(SSuperTableObj *pStable) {
         .pObj = pTable,
       };
       sdbDeleteRow(&oper);
-      pNode = pLastNode;
       numOfTables++;
     }
 
     mgmtDecTableRef(pTable);
   }
 
+  sdbFreeIter(pIter);
+
   mPrint("stable:%s, all child tables:%d is dropped from sdb", pStable->info.tableId, numOfTables);
 }
 
@@ -2079,7 +2058,7 @@ static int32_t mgmtRetrieveShowTables(SShowObj *pShow, char *data, int32_t rows,
 
   while (numOfRows < rows) {
     mgmtDecTableRef(pTable);
-    pShow->pNode = mgmtGetNextChildTable(pShow->pNode, &pTable);
+    pShow->pIter = mgmtGetNextChildTable(pShow->pIter, &pTable);
     if (pTable == NULL) break;
 
     // not belong to current db
diff --git a/src/mnode/src/mgmtUser.c b/src/mnode/src/mgmtUser.c
index 350367e0aeefaa7b28bd1a1d19faed9119bdb63a..cc22ed2169d3c810a8c5921538b188f1dcb45746 100644
--- a/src/mnode/src/mgmtUser.c
+++ b/src/mnode/src/mgmtUser.c
@@ -155,8 +155,8 @@ SUserObj *mgmtGetUser(char *name) {
   return (SUserObj *)sdbGetRow(tsUserSdb, name);
 }
 
-void *mgmtGetNextUser(void *pNode, SUserObj **pUser) { 
-  return sdbFetchRow(tsUserSdb, pNode, (void **)pUser); 
+void *mgmtGetNextUser(void *pIter, SUserObj **pUser) { 
+  return sdbFetchRow(tsUserSdb, pIter, (void **)pUser); 
 }
 
 void mgmtIncUserRef(SUserObj *pUser) { 
@@ -300,7 +300,7 @@ static int32_t mgmtRetrieveUsers(SShowObj *pShow, char *data, int32_t rows, void
   char     *pWrite;
 
   while (numOfRows < rows) {
-    pShow->pNode = mgmtGetNextUser(pShow->pNode, &pUser);
+    pShow->pIter = mgmtGetNextUser(pShow->pIter, &pUser);
     if (pUser == NULL) break;
     
     cols = 0;
@@ -504,15 +504,13 @@ static void mgmtProcessDropUserMsg(SQueuedMsg *pMsg) {
 }
 
 void  mgmtDropAllUsers(SAcctObj *pAcct)  {
-  void *    pNode = NULL;
-  void *    pLastNode = NULL;
+  void *    pIter = NULL;
   int32_t   numOfUsers = 0;
   int32_t   acctNameLen = strlen(pAcct->user);
   SUserObj *pUser = NULL;
 
   while (1) {
-    pLastNode = pNode;
-    pNode = mgmtGetNextUser(pNode, &pUser);
+    pIter = mgmtGetNextUser(pIter, &pUser);
     if (pUser == NULL) break;
 
     if (strncmp(pUser->acct, pAcct->user, acctNameLen) == 0) {
@@ -522,13 +520,14 @@ void  mgmtDropAllUsers(SAcctObj *pAcct)  {
         .pObj = pUser,
       };
       sdbDeleteRow(&oper);
-      pNode = pLastNode;
       numOfUsers++;
     }
 
     mgmtDecUserRef(pUser);
   }
 
+  sdbFreeIter(pIter);
+
   mTrace("acct:%s, all users:%d is dropped from sdb", pAcct->user, numOfUsers);
 }
 
diff --git a/src/mnode/src/mgmtVgroup.c b/src/mnode/src/mgmtVgroup.c
index b87c6ad7274dceb0463827f731b6f4c912d9613d..f8447a31fd06faf6d8dcb76286fc611c72f80b4c 100644
--- a/src/mnode/src/mgmtVgroup.c
+++ b/src/mnode/src/mgmtVgroup.c
@@ -288,8 +288,8 @@ SVgObj *mgmtGetAvailableVgroup(SDbObj *pDb) {
   return pDb->pHead;
 }
 
-void *mgmtGetNextVgroup(void *pNode, SVgObj **pVgroup) { 
-  return sdbFetchRow(tsVgroupSdb, pNode, (void **)pVgroup); 
+void *mgmtGetNextVgroup(void *pIter, SVgObj **pVgroup) { 
+  return sdbFetchRow(tsVgroupSdb, pIter, (void **)pVgroup); 
 }
 
 void mgmtCreateVgroup(SQueuedMsg *pMsg, SDbObj *pDb) {
@@ -429,10 +429,10 @@ int32_t mgmtGetVgroupMeta(STableMetaMsg *pMeta, SShowObj *pShow, void *pConn) {
 
   if (NULL == pTable) {
     pShow->numOfRows = pDb->numOfVgroups;
-    pShow->pNode = pDb->pHead;
+    pShow->pIter = pDb->pHead;
   } else {
     pShow->numOfRows = 1;
-    pShow->pNode = pVgroup;
+    pShow->pIter = pVgroup;
   }
 
    mgmtDecDbRef(pDb);
@@ -457,9 +457,9 @@ int32_t mgmtRetrieveVgroups(SShowObj *pShow, char *data, int32_t rows, void *pCo
   }
 
   while (numOfRows < rows) {
-    pVgroup = (SVgObj *) pShow->pNode;
+    pVgroup = (SVgObj *) pShow->pIter;
     if (pVgroup == NULL) break;
-    pShow->pNode = (void *) pVgroup->next;
+    pShow->pIter = (void *) pVgroup->next;
 
     cols = 0;
 
@@ -749,14 +749,12 @@ static void mgmtProcessVnodeCfgMsg(SRpcMsg *rpcMsg) {
 }
 
 void mgmtDropAllDnodeVgroups(SDnodeObj *pDropDnode) {
-  void *  pNode = NULL;
-  void *  pLastNode = NULL;
+  void *  pIter = NULL;
   SVgObj *pVgroup = NULL;
   int32_t numOfVgroups = 0;
 
   while (1) {
-    pLastNode = pNode;
-    pNode = mgmtGetNextVgroup(pNode, &pVgroup);
+    pIter = mgmtGetNextVgroup(pIter, &pVgroup);
     if (pVgroup == NULL) break;
 
     if (pVgroup->vnodeGid[0].dnodeId == pDropDnode->dnodeId) {
@@ -766,24 +764,23 @@ void mgmtDropAllDnodeVgroups(SDnodeObj *pDropDnode) {
         .pObj = pVgroup,
       };
       sdbDeleteRow(&oper);
-      pNode = pLastNode;
       numOfVgroups++;
       continue;
     }
     mgmtDecVgroupRef(pVgroup);
   }
+
+  sdbFreeIter(pIter);
 }
 
 void mgmtDropAllDbVgroups(SDbObj *pDropDb, bool sendMsg) {
-  void *pNode = NULL;
-  void *pLastNode = NULL;
+  void *  pIter = NULL;
   int32_t numOfVgroups = 0;
   SVgObj *pVgroup = NULL;
 
   mPrint("db:%s, all vgroups will be dropped from sdb", pDropDb->name);
   while (1) {
-    pLastNode = pNode;
-    pNode = mgmtGetNextVgroup(pNode, &pVgroup);
+    pIter = mgmtGetNextVgroup(pIter, &pVgroup);
     if (pVgroup == NULL) break;
 
     if (pVgroup->pDb == pDropDb) {
@@ -793,7 +790,6 @@ void mgmtDropAllDbVgroups(SDbObj *pDropDb, bool sendMsg) {
         .pObj = pVgroup,
       };
       sdbDeleteRow(&oper);
-      pNode = pLastNode;
       numOfVgroups++;
 
       if (sendMsg) {
@@ -804,5 +800,7 @@ void mgmtDropAllDbVgroups(SDbObj *pDropDb, bool sendMsg) {
     mgmtDecVgroupRef(pVgroup);
   }
 
+  sdbFreeIter(pIter);
+
   mPrint("db:%s, all vgroups:%d is dropped from sdb", pDropDb->name, numOfVgroups);
 }
diff --git a/src/util/inc/tcache.h b/src/util/inc/tcache.h
index 2e26f8f0e3f83a4a2d315b9dafc262e8ace4ba7a..6dd707b763de06601869c00e91c4f3d6d8e652a9 100644
--- a/src/util/inc/tcache.h
+++ b/src/util/inc/tcache.h
@@ -67,6 +67,7 @@ typedef struct {
   void *       pTimer;
   SCacheStatis statistics;
   SHashObj *   pHashTable;
+  _hash_free_fn_t freeFp;
   int          numOfElemsInTrash;  // number of element in trash
   int16_t      deleting;           // set the deleting flag to stop refreshing ASAP.
   T_REF_DECLARE()
@@ -88,6 +89,7 @@ typedef struct {
  * @return
  */
 SCacheObj *taosCacheInit(void *tmrCtrl, int64_t refreshTimeInSeconds);
+SCacheObj *taosCacheInitWithCb(void *tmrCtrl, int64_t refreshTimeInSeconds, void (*freeCb)(void *data));
 
 /**
  * add data into cache
diff --git a/src/util/src/tcache.c b/src/util/src/tcache.c
index 02a5b931412c874d54dc3bb99e28574340e385d5..7d8cb1faa4c2d5f6ebdf25e32d2f2d89c6a19f41 100644
--- a/src/util/src/tcache.c
+++ b/src/util/src/tcache.c
@@ -149,6 +149,7 @@ static void taosRemoveFromTrash(SCacheObj *pCacheObj, STrashElem *pElem) {
   }
   
   pElem->pData->signature = 0;
+  if (pCacheObj->freeFp) pCacheObj->freeFp(pElem->pData->data);
   free(pElem->pData);
   free(pElem);
 }
@@ -210,7 +211,8 @@ static FORCE_INLINE void taosCacheReleaseNode(SCacheObj *pCacheObj, SCacheDataNo
   int32_t size = pNode->size;
   taosHashRemove(pCacheObj->pHashTable, pNode->key, pNode->keySize);
   
-  uTrace("key:%s is removed from cache,total:%d,size:%ldbytes", pNode->key, pCacheObj->totalSize, size);
+  uTrace("key:%s is removed from cache,total:%d,size:%ldbytes", pNode->key, pCacheObj->totalSize, size);  
+  if (pCacheObj->freeFp) pCacheObj->freeFp(pNode->data);
   free(pNode);
 }
 
@@ -380,7 +382,7 @@ static void taosCacheRefresh(void *handle, void *tmrId) {
     }
 }
 
-SCacheObj *taosCacheInit(void *tmrCtrl, int64_t refreshTime) {
+SCacheObj *taosCacheInitWithCb(void *tmrCtrl, int64_t refreshTime, void (*freeCb)(void *data)) {
   if (tmrCtrl == NULL || refreshTime <= 0) {
     return NULL;
   }
@@ -399,8 +401,9 @@ SCacheObj *taosCacheInit(void *tmrCtrl, int64_t refreshTime) {
   }
   
   // set free cache node callback function for hash table
-  taosHashSetFreecb(pCacheObj->pHashTable, taosFreeNode);
+  // taosHashSetFreecb(pCacheObj->pHashTable, taosFreeNode);
   
+  pCacheObj->freeFp = freeCb;
   pCacheObj->refreshTime = refreshTime * 1000;
   pCacheObj->tmrCtrl = tmrCtrl;
   
@@ -419,6 +422,10 @@ SCacheObj *taosCacheInit(void *tmrCtrl, int64_t refreshTime) {
   return pCacheObj;
 }
 
+SCacheObj *taosCacheInit(void *tmrCtrl, int64_t refreshTime) {
+  return taosCacheInitWithCb(tmrCtrl, refreshTime, NULL);
+}
+
 void *taosCachePut(SCacheObj *pCacheObj, const char *key, const void *pData, size_t dataSize, int duration) {
   SCacheDataNode *pNode;