[ci] refactor: explain timeout failure in metasrv unittest
@@ -7,6 +7,20 @@ assignees: ''
---
+**Hold on**: `RUST_TEST_THREADS=1 make test` will solve most timeout failures.
+
+Since `metasrv` is distributed(raft driven), it is sensitive to event delay.
+It is likely to encounter a **timeout** error when running a bunch of unit-tests in parallel.
+If in single thread mode, i.e., `RUST_TEST_THREADS=1 make test` or `RUST_TEST_THREADS=1 cargo test` passes,
+then it is very likely not a bug. E.g., the log about a delayed test can be found in
+`metasrv/_logs/*` such as:
+
+```
+2021-12-21T02:27:21.534917Z DEBUG ThreadId(221) ut{test_meta_node_snapshot_replication}:open_create_boot ...
+...
+2021-12-21T02:27:24.655324Z DEBUG ThreadId(216) ut{test_meta_node_snapshot_replication}:log{want_log=15 msg="non-voter replicated all logs"}: async_raft::metrics: enter
+```
+
**Summary**
Description for this bug.
@@ -19,6 +33,13 @@ If applicable, add screenshots to help explain your problem.
[How to get the server logs](https://databend.rs/development/how-to-get-server-logs/)
+**Logs**
+
+The logs provides a lot information for debug:
+- For databend-query unit test failure: logs are in `/query/_logs/`
+- For databend-meta unit test failure: logs are in `/metasrv/_logs/`
+- For integration test failure: logs are in `/_logs*`
+
**Additional context**
Add any other context about the problem here.
