From 0066dc9ac08748cfd81c92ca7fe0c4089f4b015f Mon Sep 17 00:00:00 2001
From: Haojun Liao <hjliao@taosdata.com>
Date: Wed, 14 Oct 2020 12:43:45 +0800
Subject: [PATCH 1/3] [td-1716]

---
 src/client/src/tscSql.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/client/src/tscSql.c b/src/client/src/tscSql.c
index ef8625da06..f73b4abb15 100644
--- a/src/client/src/tscSql.c
+++ b/src/client/src/tscSql.c
@@ -257,10 +257,21 @@ TAOS *taos_connect_a(char *ip, char *user, char *pass, char *db, uint16_t port,
 void taos_close(TAOS *taos) {
   STscObj *pObj = (STscObj *)taos;
 
-  if (pObj == NULL || pObj->signature != pObj)  {
+  if (pObj == NULL) {
+    tscDebug("(null) try to free tscObj and close dnodeConn");
     return;
   }
 
+  tscDebug("%p try to free tscObj and close dnodeConn:%p", pObj, pObj->pDnodeConn);
+  if (pObj->signature != pObj) {
+    tscDebug("%p already closed or invalid tscObj", pObj);
+    return;
+  }
+
+  // make sure that the close connection can only be executed once.
+  pObj->signature = NULL;
+  taosTmrStopA(&(pObj->pTimer));
+
   SSqlObj* pHb = pObj->pHb;
   if (pHb != NULL && atomic_val_compare_exchange_ptr(&pObj->pHb, pHb, 0) == pHb) {
     if (pHb->pRpcCtx != NULL) {  // wait for rsp from dnode

From 2a9855bbaf52c513bcb4b028ae9b764cd2a70501 Mon Sep 17 00:00:00 2001
From: Haojun Liao <hjliao@taosdata.com>
Date: Wed, 14 Oct 2020 13:02:23 +0800
Subject: [PATCH 2/3] [td-225] fix bugs found by tsim

---
 src/client/src/tscSubquery.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/client/src/tscSubquery.c b/src/client/src/tscSubquery.c
index fbbd810a19..abfe62c72c 100644
--- a/src/client/src/tscSubquery.c
+++ b/src/client/src/tscSubquery.c
@@ -258,11 +258,11 @@ static int32_t tscLaunchRealSubqueries(SSqlObj* pSql) {
   assert(numOfSub > 0);
   
   // scan all subquery, if one sub query has only ts, ignore it
-  tscDebug("%p start to launch secondary subqueries, total:%d, only:%d needs to query", pSql, pSql->subState.numOfSub, numOfSub);
+  tscDebug("%p start to launch secondary subqueries, %d out of %d needs to query", pSql, numOfSub, pSql->subState.numOfSub);
 
   //the subqueries that do not actually launch the secondary query to virtual node is set as completed.
   SSubqueryState* pState = &pSql->subState;
-  pState->numOfRemain = pState->numOfSub;
+  pState->numOfRemain = numOfSub;
 
   bool success = true;
   

From 4c22b72d0663b3aa9b85f2ac0efaceb31d64e00e Mon Sep 17 00:00:00 2001
From: Haojun Liao <hjliao@taosdata.com>
Date: Wed, 14 Oct 2020 14:31:46 +0800
Subject: [PATCH 3/3] [td-225]

---
 src/util/src/tcache.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/util/src/tcache.c b/src/util/src/tcache.c
index 2896481574..6e20c1708d 100644
--- a/src/util/src/tcache.c
+++ b/src/util/src/tcache.c
@@ -558,8 +558,8 @@ void taosAddToTrashcan(SCacheObj *pCacheObj, SCacheDataNode *pNode) {
   pCacheObj->numOfElemsInTrash++;
   __cache_unlock(pCacheObj);
 
-  uDebug("cache:%s key:%p, %p move to trashcan, numOfElem in trashcan:%d", pCacheObj->name, pNode->key, pNode->data,
-      pCacheObj->numOfElemsInTrash);
+  uDebug("cache:%s key:%p, %p move to trashcan, pTrashElem:%p, numOfElem in trashcan:%d", pCacheObj->name,
+      pNode->key, pNode->data, pElem, pCacheObj->numOfElemsInTrash);
 }
 
 void taosTrashcanEmpty(SCacheObj *pCacheObj, bool force) {