In the current tez branch, mini cluster unit tests are very slow. The reason is as follows:
- TezSession reuse is by default on.
- Each test case runs, and it waits for Tez AM to terminate.
- After Tez AM times out (usually after several minutes), another test case runs.
Two questions that I have are:
- Why doesn't TezSession reuse work in mini cluster?
- Why is TezSession reuse not disabled in some tests (e.g. TestAccumulator) where we explicitly set "tez.session.reuse" to false?
As for #2, I realized that "tez.session.reuse" was never set in the properties object that is passed to PigServer. I am going to upload a patch that fixes this problem in this jira.
As for #1, I don't have an answer yet. But I think we can fix this in a separate jira once we get Tez unit tests working again.