refactor some codes

src/client/src/tscSQLParser.c

@@ -4432,7 +4432,9 @@ int32_t parseLimitClause(SQueryInfo* pQueryInfo, int32_t clauseIndex, SQuerySQL*
   const char* msg1 = "slimit/soffset only available for STable query";
   const char* msg2 = "function not supported on table";
   const char* msg3 = "slimit/soffset can not apply to projection query";
-
+  const char* msg4 = "projection on super table required limitation along with order clause";
+  const char* msg5 = "ordered projection result too large";
+  
   // handle the limit offset value, validate the limit
   pQueryInfo->limit = pQuerySql->limit;
   pQueryInfo->clauseLimit = pQueryInfo->limit.limit;
@@ -4458,9 +4460,19 @@ int32_t parseLimitClause(SQueryInfo* pQueryInfo, int32_t clauseIndex, SQuerySQL*
     if (queryOnTags == true) {  // local handle the metric tag query
       pQueryInfo->command = TSDB_SQL_RETRIEVE_TAGS;
     } else {
-      if (tscProjectionQueryOnSTable(pQueryInfo, 0) &&
-          (pQueryInfo->slimit.limit > 0 || pQueryInfo->slimit.offset > 0)) {
-        return invalidSqlErrMsg(pQueryInfo->msg, msg3);
+      if (tscProjectionQueryOnSTable(pQueryInfo, 0)) {
+        if (pQueryInfo->order.orderColId != 0) {
+          if (pQueryInfo->limit.limit == -1) {
+            return invalidSqlErrMsg(pQueryInfo->msg, msg4);
+          } else if (pQueryInfo->limit.limit > 100000) { // the result set can not be larger than 10000
+            //todo use global config parameter
+            return invalidSqlErrMsg(pQueryInfo->msg, msg5);
+          }
+        }
+        
+        if (pQueryInfo->slimit.limit > 0 || pQueryInfo->slimit.offset > 0) {
+          return invalidSqlErrMsg(pQueryInfo->msg, msg3);
+        }
       }
     }