Make the result of SRANDMEMBER random

[wsehjk]

This pr is to resolve #2014.
I use Reservoir Sampling. When the number we want to select is larger than that of elements in the set, all elements are selected

[jihuayu]

This pr is to solve #2014.

Hi @wsehjk, you can use resolve #2014 instead of solve #2014. It will make GitHub auto close issue when PR has been merged.

https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword

[PragmaTwice]

Please use ./x.py format to format your code, otherwise the CI cannot pass.

[mapleFU]

Though a different sampling algorithm is used, general LGTM

[jihuayu]

You can enable the GitHub action in your repo (It is free). So that you can find the CI failing issues earlier and more easily.

https://github.com/wsehjk/kvrocks/actions

[jihuayu]

It seems like the test run fails. Fix it, victory is within sight.

By the way, you don't need to use force push to make PR only one commit; simply use the Update branch Button is ok

[wsehjk]

It seems like the test run fails. Fix it, victory is within sight.

By the way, you don't need to use force push to make PR only one commit; simply use the Update branch Button is ok

This is because the maintainer of last repo i have contributed required pr to be one commit, i think it still makes sense here.
Everytime dev branch lags behind the unstable branch， I rungit pull and git rebase unstable dev to catch up, then I have to use force-push....

[mapleFU]

LGTM