| From: | Sami Imseih <samimseih(at)gmail(dot)com> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com> |
| Cc: | PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Andres Freund <andres(at)anarazel(dot)de>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com> |
| Subject: | Re: dshash_find_or_insert vs. OOM |
| Date: | 2026-03-25 21:52:54 |
| Message-ID: | CAA5RZ0uUPCnTgKs0KPmt8ieR-K-wtVEOeT5wPjKeT=KFAfnBQw@mail.gmail.com |
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| Lists: | pgsql-hackers |
> You need to get rid of the bare blocks.
done in v4
> This verifies that dshash_dump() doesn't crash, but not that it
> produces useful output. Whether that's worth the infrastructure, I
> don't know.
I don't think dshash_dump() will be deterministic, as keys may hash
to different buckets on different platforms, perhaps. Which is why
I did not think it was a good idea to compare the output from the logs.
Testing that it does not crash seemed worthwhile to increase
the coverage.
> 408). The omissions are: some OOM cases, dshash_delete_bucket()
> successfully deletes something, concurrency case in resizing, most of
> delete_key_from_bucket(), delete_item_from_bucket() iterating more
Yes, we can probably address some of these things with more complexity.
> than once or returning false. Combining your patch with the test suite
> previously mentioned, we get up to 97.1% coverage by lines (396 of
> 408).
This is solid coverage
> So the patch definitely has some value: it adds coverage of 60+ lines
> of code. On the other hand, it still feels to me like we'd be far more
> likely to notice new dshash bugs based on its existing usages than
> because of this. If I were modifying dshash, I wouldn't run this test
> suite first; I'd run the regression tests first.
Sure, but once a bug is fixed, having direct test coverage fo this bug
in a dedicated test suite is a good thing.
The NO_OOM flag that started this discussion would not fit neatly in other
test suites, AFAICT.
--
Sami
| Attachment | Content-Type | Size |
|---|---|---|
| v4-0001-Add-test-module-for-dshash.patch | application/octet-stream | 12.9 KB |
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