[td-255] avoid memset the allocated memory to improve the query performance.

src/client/inc/tscUtil.h

@@ -174,7 +174,9 @@ void    tscClearInterpInfo(SQueryInfo* pQueryInfo);
 
 bool tscIsInsertData(char* sqlstr);
 
-int tscAllocPayload(SSqlCmd* pCmd, int size);
+// the memory is not reset in case of fast allocate payload function
+int32_t tscAllocPayloadFast(SSqlCmd *pCmd, size_t size);
+int32_t tscAllocPayload(SSqlCmd* pCmd, int size);
 
 TAOS_FIELD tscCreateField(int8_t type, const char* name, int16_t bytes);
 

src/client/src/tscServer.c

@@ -887,8 +887,9 @@ int tscBuildQueryMsg(SSqlObj *pSql, SSqlInfo *pInfo) {
 
   int32_t code = TSDB_CODE_SUCCESS;
   int32_t size = tscEstimateQueryMsgSize(pSql);
+  assert(size > 0);
 
-  if (TSDB_CODE_SUCCESS != tscAllocPayload(pCmd, size)) {
+  if (TSDB_CODE_SUCCESS != tscAllocPayloadFast(pCmd, size)) {
     tscError("%p failed to malloc for query msg", pSql);
     return TSDB_CODE_TSC_INVALID_OPERATION;  // todo add test for this
   }

src/client/src/tscUtil.c

@@ -2080,32 +2080,34 @@ bool tscIsInsertData(char* sqlstr) {
   } while (1);
 }
 
-int tscAllocPayload(SSqlCmd* pCmd, int size) {
+int32_t tscAllocPayloadFast(SSqlCmd *pCmd, size_t size) {
   if (pCmd->payload == NULL) {
     assert(pCmd->allocSize == 0);
 
-    pCmd->payload = (char*)calloc(1, size);
-    if (pCmd->payload == NULL) {
+    pCmd->payload = malloc(size);
+  } else if (pCmd->allocSize < size) {
+    char* tmp = realloc(pCmd->payload, size);
+    if (tmp == NULL) {
       return TSDB_CODE_TSC_OUT_OF_MEMORY;
     }
 
+    pCmd->payload = tmp;
     pCmd->allocSize = size;
-  } else {
-    if (pCmd->allocSize < (uint32_t)size) {
-      char* b = realloc(pCmd->payload, size);
-      if (b == NULL) {
-        return TSDB_CODE_TSC_OUT_OF_MEMORY;
-      }
+  }
 
-      pCmd->payload = b;
-      pCmd->allocSize = size;
-    }
+  assert(pCmd->allocSize >= size);
+  return TSDB_CODE_SUCCESS;
+}
 
+int32_t tscAllocPayload(SSqlCmd* pCmd, int size) {
+  assert(size > 0);
+
+  int32_t code = tscAllocPayloadFast(pCmd, (size_t) size);
+  if (code == TSDB_CODE_SUCCESS) {
     memset(pCmd->payload, 0, pCmd->allocSize);
   }
 
-  assert(pCmd->allocSize >= (uint32_t)size && size > 0);
-  return TSDB_CODE_SUCCESS;
+  return code;
 }
 
 TAOS_FIELD tscCreateField(int8_t type, const char* name, int16_t bytes) {