diff --git a/src/common/src/tglobal.c b/src/common/src/tglobal.c
index 38ae56eb241139cf33b56213832c8c6797ba4d1c..9e9b2056b19ea1bb2f593bbc79d28aa95edcd552 100644
--- a/src/common/src/tglobal.c
+++ b/src/common/src/tglobal.c
@@ -84,7 +84,7 @@ int8_t  tsTscEnableRecordSql = 0;
 
 // the maximum number of results for projection query on super table that are returned from
 // one virtual node, to order according to timestamp
-int32_t tsMaxNumOfOrderedResults = 100000;
+int32_t tsMaxNumOfOrderedResults = 1000000;
 
 // 10 ms for sliding time, the value will changed in case of time precision changed
 int32_t tsMinSlidingTime = 10;
@@ -1017,8 +1017,8 @@ static void doInitGlobalConfig(void) {
   cfg.ptr = &tsMaxNumOfOrderedResults;
   cfg.valType = TAOS_CFG_VTYPE_INT32;
   cfg.cfgType = TSDB_CFG_CTYPE_B_CONFIG | TSDB_CFG_CTYPE_B_CLIENT | TSDB_CFG_CTYPE_B_SHOW;
-  cfg.minValue = TSDB_MAX_SQL_LEN;
-  cfg.maxValue = TSDB_MAX_ALLOWED_SQL_LEN;
+  cfg.minValue = 100000;
+  cfg.maxValue = 100000000;
   cfg.ptrLength = 0;
   cfg.unitType = TAOS_CFG_UTYPE_NONE;
   taosInitConfigOption(cfg);
diff --git a/src/query/src/qTsbuf.c b/src/query/src/qTsbuf.c
index 4cf05dd2c7703c7879410faa2632e17a16d595fd..99572f6e9345b933434e3685ecb79750a04388fc 100644
--- a/src/query/src/qTsbuf.c
+++ b/src/query/src/qTsbuf.c
@@ -375,6 +375,16 @@ STSBlock* readDataFromDisk(STSBuf* pTSBuf, int32_t order, bool decomp) {
   sz = fread(pBlock->payload, (size_t)pBlock->compLen, 1, pTSBuf->f);
 
   if (decomp) {
+    if (pBlock->numOfElem * TSDB_KEYSIZE > pTSBuf->tsData.allocSize) {
+      pTSBuf->tsData.rawBuf = realloc(pTSBuf->tsData.rawBuf, pBlock->numOfElem * TSDB_KEYSIZE);
+      pTSBuf->tsData.allocSize = pBlock->numOfElem * TSDB_KEYSIZE;
+    }
+
+    if (pBlock->numOfElem * TSDB_KEYSIZE > pTSBuf->bufSize) {
+      pTSBuf->assistBuf = realloc(pTSBuf->assistBuf, pBlock->numOfElem * TSDB_KEYSIZE);
+      pTSBuf->bufSize = pBlock->numOfElem * TSDB_KEYSIZE;
+    }    
+    
     pTSBuf->tsData.len =
         tsDecompressTimestamp(pBlock->payload, pBlock->compLen, pBlock->numOfElem, pTSBuf->tsData.rawBuf,
                               pTSBuf->tsData.allocSize, TWO_STAGE_COMP, pTSBuf->assistBuf, pTSBuf->bufSize);
@@ -471,7 +481,7 @@ void tsBufAppend(STSBuf* pTSBuf, int32_t id, tVariant* tag, const char* pData, i
   
   // the size of raw data exceeds the size of the default prepared buffer, so
   // during getBufBlock, the output buffer needs to be large enough.
-  if (ptsData->len >= ptsData->threshold) {
+  if (ptsData->len >= ptsData->threshold - TSDB_KEYSIZE) {
     writeDataToDisk(pTSBuf);
     shrinkBuffer(ptsData);
   }
@@ -603,6 +613,10 @@ static void tsBufGetBlock(STSBuf* pTSBuf, int32_t groupIndex, int32_t blockIndex
     expandBuffer(&pTSBuf->tsData, (int32_t)s);
   }
   
+  if (s > pTSBuf->bufSize) {
+    pTSBuf->assistBuf = realloc(pTSBuf->assistBuf, s);
+    pTSBuf->bufSize = (int32_t)s;
+  }    
   pTSBuf->tsData.len =
       tsDecompressTimestamp(pBlock->payload, pBlock->compLen, pBlock->numOfElem, pTSBuf->tsData.rawBuf,
                             pTSBuf->tsData.allocSize, TWO_STAGE_COMP, pTSBuf->assistBuf, pTSBuf->bufSize);