It is not so easy to use a linter on all the rules as the tool I used
fails to honor .gitignore files. It ends up checking many generated
files and comes up with many false errors.
I used the following commands to check rules and attempt to fix all
problems:
- `git ls-files | xargs eclint check`
- `git ls-files | xargs eclint fix`
However, eclint was not able to fix all the problems for me
automatically. I used the check command output and fixed them by hand.
Sometimes our `isolation_insert_vs_vacuum` test would fail like this.
```diff
step s2-vacuum-analyze:
VACUUM ANALYZE test_insert_vacuum;
-
+ <waiting ...>
step s1-commit:
COMMIT;
+step s2-vacuum-analyze: <... completed>
```
The reason seems to be that VACUUM ANALYZE tries to take some locks that
conflict with the other transaction, but these locks somehow get
released or VACUUM ANALYZE stops waiting for them. This is somewhat
expected since VACUUM has some special locking logic.
To solve the flakyness we now trigger VACUUM ANALYZE to always report as
blocking and after that we wait explicitly wait for it to complete. This
is done
like is suggested by the flaky test tips from postgres:
c68a183990/src/test/isolation/README (L152)
I've confirmed that this fixes the issue suing our flaky-test-debugging
CI workflow.
Currently in mx isolation tests the setup is the same except the creation of tables. Isolation framework lets us define multiple `setup` stages, therefore I thought that we can put the `mx_setup` to one file and prepend this prior to running tests.
How the structure works:
- cpp is used before running isolation tests to preprocess spec files. This way we can include any file we want to. Currently this is used to include mx common part.
- spec files are put to `/build/specs` for clear separation between generated files and template files
- a symbolic link is created for `/expected` in `build/expected/`.
- when running isolation tests, as the `inputdir`, `build` is passed so it runs the spec files from `build/specs` and checks the expected output from `build/expected`.
`/specs` is renamed as `/spec` because postgres first look at the `specs` file under current directory, so this is renamed to avoid that since we are running the isolation tests from `build/specs` now.
Note: now we use `//` instead of `#` in comments in spec files, because cpp interprets `#` as a directive and it ignores `//`.
Hanefi Onaldi
Jelte Fennema
SaitTalhaNisanci