diff --git a/tests/examples/c/demo.c b/tests/examples/c/demo.c
index b955401e43deae1e6da0c4fb610aeb22d950fe4c..cfeb5c8eb768a8688082231dd3b647228dc5ab28 100644
--- a/tests/examples/c/demo.c
+++ b/tests/examples/c/demo.c
@@ -76,7 +76,11 @@ int main(int argc, char *argv[]) {
   doQuery(taos, "create database if not exists test");
   doQuery(taos, "use test");
 //  doQuery(taos, "create table t1(ts timestamp, k binary(12), f nchar(2))");
-  doQuery(taos, "select m1.ts,m1.a from m1, m2 where m1.ts=m2.ts and m1.a=m2.b;");
+  for(int32_t i = 0; i< 100000; ++i) {
+    doQuery(taos, "select m1.ts,m1.a from m1, m2 where m1.ts=m2.ts and m1.a=m2.b;");
+    usleep(500000);
+  }
+
 //  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:1', 'abc')");
 //  doQuery(taos, "create table if not exists tm0 (ts timestamp, k int);");
 //  doQuery(taos, "insert into tm0 values('2020-1-1 1:1:1', 1);");