diff --git a/source/libs/executor/src/executorimpl.c b/source/libs/executor/src/executorimpl.c
index 6b4c8fb574a0a21f989fc3222489bea717a9911e..f2318c9c6a4b55a6df364f0ac8cf00fb375634c3 100644
--- a/source/libs/executor/src/executorimpl.c
+++ b/source/libs/executor/src/executorimpl.c
@@ -5718,6 +5718,10 @@ void addToDiskbasedBuf(SOrderOperatorInfo* pInfo, jmp_buf env) {
 
     int32_t pageId = -1;
     SFilePage* pPage = getNewDataBuf(pInfo->pSortInternalBuf, pInfo->sourceId, &pageId);
+    if (pPage == NULL) {
+      assert(0);
+      longjmp(env, terrno);
+    }
 
     int32_t size = blockDataGetSize(p) + sizeof(int32_t)  + p->info.numOfCols * sizeof(int32_t);
     assert(size <= getBufPageSize(pInfo->pSortInternalBuf));
@@ -5884,7 +5888,7 @@ SOperatorInfo *createOrderOperatorInfo(SOperatorInfo* downstream, SArray* pExprI
     return NULL;
   }
 
-  pInfo->sortBufSize = 1024 * 1024 * 5; // 1MB
+  pInfo->sortBufSize = 1024 * 1024 * 50; // 1MB
   pInfo->capacity    = 64*1024;
   pInfo->pDataBlock  = createOutputBuf_rv(pExprInfo, pInfo->capacity);
   pInfo->pSources    = taosArrayInit(4, POINTER_BYTES);
diff --git a/source/libs/executor/test/executorTests.cpp b/source/libs/executor/test/executorTests.cpp
index 2dd26ab534cc0c906ae85a5b99f357c5c88b2d03..3df9910ffbf828531077509183ae06cef4a694a8 100644
--- a/source/libs/executor/test/executorTests.cpp
+++ b/source/libs/executor/test/executorTests.cpp
@@ -262,7 +262,7 @@ TEST(testCase, external_sort_Test) {
   exp1->base.resSchema = createSchema(TSDB_DATA_TYPE_BINARY, 40, 2, "res1");
   taosArrayPush(pExprInfo, &exp1);
 
-  SOperatorInfo* pOperator = createOrderOperatorInfo(createDummyOperator(50000), pExprInfo, pOrderVal);
+  SOperatorInfo* pOperator = createOrderOperatorInfo(createDummyOperator(500000), pExprInfo, pOrderVal);
 
   bool newgroup = false;
   SSDataBlock* pRes = NULL;
diff --git a/source/util/src/tpagedfile.c b/source/util/src/tpagedfile.c
index 2d8fdb1fc317bce659e3e729f397ad7acedfb5fa..8e9ee1e0886721f19e7ff24caa32840376b256b5 100644
--- a/source/util/src/tpagedfile.c
+++ b/source/util/src/tpagedfile.c
@@ -13,8 +13,8 @@ typedef struct SFreeListItem {
 } SFreeListItem;
 
 typedef struct SPageDiskInfo {
-  int32_t offset;
-  int32_t length;
+  uint64_t offset;
+  int32_t  length;
 } SPageDiskInfo;
 
 typedef struct SPageInfo {
@@ -36,7 +36,7 @@ typedef struct SDiskbasedBufStatis {
 typedef struct SDiskbasedBuf {
   int32_t   numOfPages;
   int64_t   totalBufSize;
-  int64_t   fileSize;            // disk file size
+  uint64_t  fileSize;            // disk file size
   FILE*     file;
   int32_t   allocateId;          // allocated page id
   char*     path;                // file path
@@ -49,7 +49,7 @@ typedef struct SDiskbasedBuf {
   void*     assistBuf;           // assistant buffer for compress/decompress data
   SArray*   pFree;               // free area in file
   bool      comp;                // compressed before flushed to disk
-  int32_t   nextPos;             // next page flush position
+  uint64_t  nextPos;             // next page flush position
 
   uint64_t  qId;                 // for debug purpose
   SDiskbasedBufStatis statis;
@@ -130,7 +130,7 @@ static char* doDecompressData(void* data, int32_t srcSize, int32_t *dst, SDiskba
   return data;
 }
 
-static int32_t allocatePositionInFile(SDiskbasedBuf* pResultBuf, size_t size) {
+static uint64_t allocatePositionInFile(SDiskbasedBuf* pResultBuf, size_t size) {
   if (pResultBuf->pFree == NULL) {
     return pResultBuf->nextPos;
   } else {
@@ -165,10 +165,16 @@ static char* doFlushPageToDisk(SDiskbasedBuf* pResultBuf, SPageInfo* pg) {
     pResultBuf->nextPos += size;
 
     int32_t ret = fseek(pResultBuf->file, pg->info.offset, SEEK_SET);
-    assert(ret == 0);
+    if (ret != 0) {
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      return NULL;
+    }
 
     ret = (int32_t) fwrite(t, 1, size, pResultBuf->file);
-    assert(ret == size);
+    if (ret != size) {
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      return NULL;
+    }
 
     if (pResultBuf->fileSize < pg->info.offset + pg->info.length) {
       pResultBuf->fileSize = pg->info.offset + pg->info.length;
@@ -186,13 +192,15 @@ static char* doFlushPageToDisk(SDiskbasedBuf* pResultBuf, SPageInfo* pg) {
 
     //3. write to disk.
     int32_t ret = fseek(pResultBuf->file, pg->info.offset, SEEK_SET);
-    if (ret != 0) {  // todo handle the error case
-
+    if (ret != 0) {
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      return NULL;
     }
 
     ret = (int32_t)fwrite(t, size, 1, pResultBuf->file);
-    if (ret != size) {  // todo handle the error case
-
+    if (ret != size) {
+      terrno = TAOS_SYSTEM_ERROR(errno);
+      return NULL;
     }
 
     if (pResultBuf->fileSize < pg->info.offset + pg->info.length) {
@@ -207,7 +215,6 @@ static char* doFlushPageToDisk(SDiskbasedBuf* pResultBuf, SPageInfo* pg) {
   pg->info.length = size;
 
   pResultBuf->statis.flushBytes += pg->info.length;
-
   return ret;
 }
 
@@ -346,6 +353,11 @@ SFilePage* getNewDataBuf(SDiskbasedBuf* pResultBuf, int32_t groupId, int32_t* pa
     availablePage = evicOneDataPage(pResultBuf);
   }
 
+  // Failed to allocate a new buffer page, and there is an error occurs.
+  if (availablePage == NULL && terrno != 0) {
+    return NULL;
+  }
+
   // register new id in this group
   *pageId = (++pResultBuf->allocateId);
 
@@ -354,7 +366,6 @@ SFilePage* getNewDataBuf(SDiskbasedBuf* pResultBuf, int32_t groupId, int32_t* pa
 
   // add to LRU list
   assert(listNEles(pResultBuf->lruList) < pResultBuf->inMemPages && pResultBuf->inMemPages > 0);
-
   lruListPushFront(pResultBuf->lruList, pi);
 
   // add to hash map