ARROW-11896: [Rust] Disable Debug symbols on CI test builds

[alamb]

The theory is that the inclusion of debug symbols is increasing the memory requirements of compiling the test binaries which is causing the tests to hit the CI builder's memory limits (and being OOM killed).

Changes:
Since the debug symbols aren't used for tests, run the CI tests without them to save memory

In theory this might also make the builds faster as well

@nevi-me and I theorize (without proof) that some new release of a dependency pushed the memory usage over the github builder limit which is why we started seeing this all of a sudden on master without any obvious corresponding code change

[github-actions]

https://issues.apache.org/jira/browse/ARROW-11896

[codecov-io]

Codecov Report

Merging #9653 (7bd587e) into master (dec5ab9) will decrease coverage by 0.01%.
The diff coverage is 56.25%.

@@ Coverage Diff @@## master #9653 +/- ##
==========================================
- Coverage 82.51% 82.50% -0.02% 
==========================================
Files 245 245 Lines 57329 57347 +18 ==========================================
+ Hits 47306 47312 +6 - Misses 10023 10035 +12 

Impacted Files	Coverage Δ
rust/arrow/src/array/array_list.rs	92.88% <ø> (-0.07%)	⬇️
rust/arrow/src/datatypes/native.rs	76.59% <22.22%> (-12.88%)	⬇️
rust/arrow/src/array/array_binary.rs	91.82% <100.00%> (ø)
rust/arrow/src/array/array_primitive.rs	95.00% <100.00%> (+0.04%)	⬆️
rust/arrow/src/array/array_string.rs	96.06% <100.00%> (ø)
rust/datafusion/src/physical_plan/merge.rs	76.56% <100.00%> (ø)
rust/parquet/src/encodings/encoding.rs	95.05% <0.00%> (+0.19%)	⬆️
rust/arrow/src/array/equal/utils.rs	76.47% <0.00%> (+0.98%)	⬆️

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[nevi-me]

@alamb this seems to have worked. I'm triggering the jobs to run again, if it passes again; it's a 👍 from me.

We've already observed from our local repro attempts that there wasn't any specific PR that caused the issue. It could be that some dependency updates suddenly caused us to hit the memory limits on CI, as you're exploring.

[jorgecarleitao]

Great thinking and cool idea. 🚢

[jorgecarleitao]

Curious, when the CI fails, we will no longer have the trace, right? Isn't that a concern whenever we want to share logs e.g. on PRs, mailing lists, etc?

[nevi-me]

Curious, when the CI fails, we will no longer have the trace, right? Isn't that a concern whenever we want to share logs e.g. on PRs, mailing lists, etc?

A compromise could be to disable debug symbols only on the Debian Rust stable runs, as the other platforms seem fine.

[alamb]

We've already observed from our local repro attempts that there wasn't any specific PR that caused the issue. It could be that some dependency updates suddenly caused us to hit the memory limits on CI, as you're exploring.

I think this is a likely theory but I don't have any specific data to prove one way or the other

Curious, when the CI fails, we will no longer have the trace, right? Isn't that a concern whenever we want to share logs e.g. on PRs, mailing lists, etc?

I think we will still get backtraces even without "debug" symbols (the debug symbols are used by gdb / lldb to be able to interpret core dumps / map local variables to memory locations, etc).

To confirm this theory I ran the following (on my mac, will try on linux shortly) and the trace is still present

(arrow_dev) alamb@MacBook-Pro:~/Software/arrow2/rust$ RUST_BACKTRACE=1 RUSTFLAGS="-C debuginfo=0" cargo test -p arrow -- test_null_list_primitive
Finished test [unoptimized + debuginfo] target(s) in 0.10s
Running target/debug/deps/arrow-99caf14857691f1e
running 1 test
test array::array::tests::test_null_list_primitive ... FAILED
failures:
---- array::array::tests::test_null_list_primitive stdout ----
thread 'array::array::tests::test_null_list_primitive' panicked at 'test error', arrow/src/array/array.rs:621:9
stack backtrace:
0: std::panicking::begin_panic
1: arrow::array::array::tests::test_null_list_primitive
2: arrow::array::array::tests::test_null_list_primitive::{{closure}}
3: core::ops::function::FnOnce::call_once
4: core::ops::function::FnOnce::call_once
at /rustc/cb75ad5db02783e8b0222fee363c5f63f7e2cf5b/library/core/src/ops/function.rs:227:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
failures:
array::array::tests::test_null_list_primitive
test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 667 filtered out; finished in 0.14s
error: test failed, to rerun pass '-p arrow --lib'

A compromise could be to disable debug symbols only on the Debian Rust stable runs, as the other platforms seem fine.

Yeah -- in fact this PR doesn't set the debug flags for Windows or Mac (I believe the Mac builders are larger -- 15GB of memory on github, and windows debugging symbols work significantly different)

[alamb]

I plan to run this on a linux machine (to confirm the backtrace behavior and then merge it in)

[alamb]

I still get backtraces on my linux machine (Ubuntu 20.04). !

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.50%. Comparing base (dec5ab9) to head (7bd587e).

Additional details and impacted files

@@ Coverage Diff @@## master #9653 +/- ##
==========================================
- Coverage 82.51% 82.50% -0.02% 
==========================================
Files 245 245 Lines 57329 57347 +18 ==========================================
+ Hits 47306 47312 +6 - Misses 10023 10035 +12 

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