Doroszlai, Attila

Thanks @chungen0126 for the fix, @smengcl for the review.

> Overall idea makes sense, but why do we do so much manual cache management? It seems like https://github.com/actions/setup-java and https://github.com/actions/setup-node can handle it for us. Are there extra requirements...

Thanks @errose28, @smengcl for the review.

It turns out `cache/save` cannot overwrite existing cache, so I reverted this. Will post new PR.

Thanks @whbing for working on this. Unfortunately, I don't think using an empty prefix will solve this. - Read-only workload will never work without prior writes. (There are standalone read-only...

> The prefix is always non-empty due to the following code, regardless of whether the prefix used. > > https://github.com/apache/ozone/blob/06c7cb419c141a0525c3d91063517b9912c9ff70/hadoop-ozone/tools/src/main/java/org/apache/hadoop/ozone/freon/BaseFreonGenerator.java#L287-L292 > > * It does not impact write op even...

> It can fix problem 1 if empty prefix allowed when writing (before read op) So the problem is worked around by executing write-only workload before read or read/write workload....