diff --git a/source/libs/qworker/src/qwMem.c b/source/libs/qworker/src/qwMem.c
index 3a4a9fc23d..6f076a8f69 100644
--- a/source/libs/qworker/src/qwMem.c
+++ b/source/libs/qworker/src/qwMem.c
@@ -78,12 +78,13 @@ int32_t qwInitJobHash(void) {
 void qwDestroySession(QW_FPARAMS_DEF, SQWJobInfo *pJobInfo, void* session) {
   char id[sizeof(tId) + sizeof(eId) + 1] = {0};
   QW_SET_TEID(id, tId, eId);
-  int32_t remainSessions = atomic_sub_fetch_32(&pJobInfo->memInfo->remainSession, 1);
 
   (void)taosHashRemove(pJobInfo->pSessions, id, sizeof(id));
 
   taosMemPoolDestroySession(gMemPoolHandle, session);
 
+  int32_t remainSessions = atomic_sub_fetch_32(&pJobInfo->memInfo->remainSession, 1);
+
   if (0 == remainSessions) {
     QW_LOCK(QW_WRITE, &pJobInfo->lock);
     if (0 == taosHashGetSize(pJobInfo->pSessions) && 0 == atomic_load_32(&pJobInfo->memInfo->remainSession)) {
diff --git a/source/util/test/memPoolTest.cpp b/source/util/test/memPoolTest.cpp
index 0181f2ea95..e5a3f203b8 100644
--- a/source/util/test/memPoolTest.cpp
+++ b/source/util/test/memPoolTest.cpp
@@ -735,7 +735,7 @@ void mptRetireJobsCb(int64_t retireSize, int32_t errCode) {
   int64_t retiredSize = 0;
   while (retiredSize < retireSize && NULL != pJob) {
     if (atomic_load_8(&pJob->retired) || 0 == atomic_load_8(&pJob->initDone)) {
-      pJob = (SMPTJobInfo*)taosHashIterate(mptCtx.pJobs, NULL);
+      pJob = (SMPTJobInfo*)taosHashIterate(mptCtx.pJobs, pJob);
       continue;
     }
 
@@ -753,7 +753,7 @@ void mptRetireJobsCb(int64_t retireSize, int32_t errCode) {
           jobId, aSize, retireSize, retiredSize);
     }
 
-    pJob = (SMPTJobInfo*)taosHashIterate(mptCtx.pJobs, NULL);
+    pJob = (SMPTJobInfo*)taosHashIterate(mptCtx.pJobs, pJob);
   }
 
   taosHashCancelIterate(mptCtx.pJobs, pJob);
@@ -1492,8 +1492,8 @@ void mptPrintTestBeginInfo(char* caseName, SMPTestParam* param) {
 #if 1
 
 #if 0
-TEST(FuncTest, SysMemoryPerfTest) {
-  char* caseName = "FuncTest:SingleThreadTest";
+TEST(PerfTest, GetSysAvail) {
+  char* caseName = "PerfTest:GetSysAvail";
   int32_t code = 0;
 
   int64_t msize = 1048576UL*10240;
@@ -1518,6 +1518,39 @@ TEST(FuncTest, SysMemoryPerfTest) {
 }
 #endif
 
+#if 0
+TEST(PerfTest, allocLatency) {
+  char* caseName = "PerfTest:allocLatency";
+  int32_t code = 0;
+
+  int64_t msize = 10;
+  char* p = NULL;
+  void* pSession = NULL;
+  void* pJob = NULL;
+  
+  mptInitPool();
+
+  memset(mptCtx.jobCtxs, 0, sizeof(*mptCtx.jobCtxs));
+
+  assert(0 == taosMemPoolCallocJob(0, 0, (void**)&pJob));
+  assert(0 == taosMemPoolInitSession(gMemPoolHandle, &pSession, pJob, "id"));
+
+  int32_t loopTimes = 1000000;
+  int64_t st = taosGetTimestampUs();
+
+  mptEnableMemoryPoolUsage(gMemPoolHandle, pSession);
+  for (int32_t i = 0; i < loopTimes; ++i) {
+    p = mptMemoryMalloc(msize);
+    assert(0 == code);
+  }
+  int64_t totalUs = taosGetTimestampUs() - st;
+  mptDisableMemoryPoolUsage();
+  
+  printf("%d times alloc %" PRId64 " bytes, total time:%" PRId64 "us, avg:%dus\n", loopTimes, totalUs, totalUs/loopTimes);
+}
+#endif
+
+
 #if 0
 TEST(FuncTest, SingleThreadTest) {
   char* caseName = "FuncTest:SingleThreadTest";