Redis [BUG] Redis benchmark can't run when config save not set

Describe the bug

Redis benchmark can't run when config save not set, and throw ERROR: failed to fetch CONFIG from ***host***.

First of all, it doesn't make sense that benchmark can't work without that config.

Secondly, there are some cloud providers providing redis servers but using own backup tech and forcing config save empty, and at these situations, benchmark can't run on these servers forever.

To reproduce

1. Start a redis server using config file with no config save ;
2. Run benchmark on it.

Expected behavior

Run as normal.

Additional information

Forgive my poor English. And redis benchmark 5.5 works properly but 6.2 has this problem.

Comment From: oranagra

@AnnAngela please check the unstable branch. this was already resolved by #8916 i've just tested to confirm. please let me know if you find that i'm wrong.

Comment From: AnnAngela

@AnnAngela please check the unstable branch. this was already resolved by #8916 i've just tested to confirm. please let me know if you find that i'm wrong.

I tried unstable version. And yes, it can run. But there is a warning with same message, IDK if it's designed to show that message.

Comment From: oranagra

@AnnAngela as far as i can tell, just the fact the server doesn't have any save config, doesn't cause that warning (and segmentation fault in last release of 6.2).

oran@Oran-laptop:~/work/redis2$ src/redis-server --save "" > /dev/null &
[1] 14713
oran@Oran-laptop:~/work/redis2$ redis-cli config get save
1) "save"
2) ""
oran@Oran-laptop:~/work/redis2$ src/redis-benchmark 
PING_INLINE: rps=135900.0 (overall: 126666.7) avg_msec=0.190 (overall: 0.205)
^C

the problem is that if you're connecting to some redis provider that doesn't support that save config entirely, it shows a warning and used to crash. maybe we could tone down the warning message in some way, but i don't see it as a significant issue.

Comment From: AnnAngela

Yes, you are right. This is not serious problem and I will leave it away. Thank you for you fixing!

But I think that should be mentioned in benchmark document.