diff --git a/source/libs/executor/src/sortoperator.c b/source/libs/executor/src/sortoperator.c
index 81899b68cd51a4c11a5f12728145b07090e56839..77eeb242103714ff8b16394eaefc4478f15f07cc 100644
--- a/source/libs/executor/src/sortoperator.c
+++ b/source/libs/executor/src/sortoperator.c
@@ -392,10 +392,8 @@ SOperatorInfo* createMultiwaySortMergeOperatorInfo(SOperatorInfo** downStreams,
 
   pInfo->bufPageSize   = getProperSortPageSize(rowSize);
 
-  uint32_t numOfSources = taosArrayGetSize(pSortInfo);
-  numOfSources = TMAX(4, numOfSources);
-
-  pInfo->sortBufSize    = numOfSources * pInfo->bufPageSize;
+  // one additional is reserved for merged result.
+  pInfo->sortBufSize   = pInfo->bufPageSize * (numStreams + 1);
 
   pOperator->fpSet =
       createOperatorFpSet(doOpenMultiwaySortMergeOperator, doMultiwaySortMerge, NULL, NULL,
diff --git a/source/libs/executor/src/tsort.c b/source/libs/executor/src/tsort.c
index 1502387360cb5a1722949e243e3bb054ef15d61d..00e07c719946171cc396ce0cac1ca1504f663bb4 100644
--- a/source/libs/executor/src/tsort.c
+++ b/source/libs/executor/src/tsort.c
@@ -195,6 +195,11 @@ static int32_t doAddToBuf(SSDataBlock* pDataBlock, SSortHandle* pHandle) {
   return doAddNewExternalMemSource(pHandle->pBuf, pHandle->pOrderedSource, pBlock, &pHandle->sourceId);
 }
 
+static void setCurrentSourceIsDone(SSortSource* pSource, SSortHandle* pHandle) {
+  pSource->src.rowIndex = -1;
+  ++pHandle->numOfCompletedSources;
+}
+
 static int32_t sortComparInit(SMsortComparParam* cmpParam, SArray* pSources, int32_t startIndex, int32_t endIndex, SSortHandle* pHandle) {
   cmpParam->pSources  = taosArrayGet(pSources, startIndex);
   cmpParam->numOfSources = (endIndex - startIndex + 1);
@@ -205,8 +210,10 @@ static int32_t sortComparInit(SMsortComparParam* cmpParam, SArray* pSources, int
     for (int32_t i = 0; i < cmpParam->numOfSources; ++i) {
       SSortSource* pSource = cmpParam->pSources[i];
 
+      // set current source is done
       if (taosArrayGetSize(pSource->pageIdList) == 0) {
-        return TSDB_CODE_SUCCESS;
+        setCurrentSourceIsDone(pSource, pHandle);
+        continue;
       }
 
       SPageInfo* pPgInfo = *(SPageInfo**)taosArrayGet(pSource->pageIdList, pSource->pageIndex);
@@ -233,10 +240,9 @@ static int32_t sortComparInit(SMsortComparParam* cmpParam, SArray* pSources, int
       SSortSource* pSource = cmpParam->pSources[i];
       pSource->src.pBlock = pHandle->fetchfp(pSource->param);
 
-      // set current source id done
+      // set current source is done
       if (pSource->src.pBlock == NULL) {
-        pSource->src.rowIndex = -1;
-        ++pHandle->numOfCompletedSources;
+        setCurrentSourceIsDone(pSource, pHandle);
       }
     }
   }
diff --git a/source/os/src/osSocket.c b/source/os/src/osSocket.c
index 4a0d9e286629dfb4c788eb489ab41f9c6802d831..4d61e7036d695e4c0df34ef88d02a4609e6dcf1e 100644
--- a/source/os/src/osSocket.c
+++ b/source/os/src/osSocket.c
@@ -946,8 +946,7 @@ int32_t taosGetFqdn(char *fqdn) {
 #endif  // __APPLE__
   int32_t ret = getaddrinfo(hostname, NULL, &hints, &result);
   if (!result) {
-    // printf("failed to get fqdn, code:%d, reason:%s", ret, gai_strerror(ret));
-    assert(0);
+    fprintf(stderr,"failed to get fqdn, code:%d, reason:%s", ret, gai_strerror(ret));
     return -1;
   }