feat(python): Raise an error when users try to use Polars API in a fork()-without-execve() child #19149
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itamarst
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ritchie46,
c-peters,
alexander-beedie,
MarcoGorelli and
reswqa
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ritchie46
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Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #19149 +/- ##
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- Coverage 79.78% 79.76% -0.03%
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Files 1531 1531
Lines 208445 208455 +10
Branches 2913 2916 +3
==========================================
- Hits 166301 166264 -37
- Misses 41593 41639 +46
- Partials 551 552 +1 ☔ View full report in Codecov by Sentry. |
ritchie46
reviewed
Oct 8, 2024
| # fork() breaks Polars thread pool. Instead of silently hanging when users do | ||
| # this, e.g. by using multiprocessing's footgun default setting on Linux, warn | ||
| # them instead: | ||
| def __install_postfork_hook() -> None: |
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Nice fix. Any idea of the startup cost of this?
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I suspect it's not meaningfully slower, but I'll measure it tomorrow.
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This appears to add 3 or 4 µs to import polars. This doesn't seem like a problem to me.
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Alright. Thanks @itamarst. Nice that we can catch those deadlocks now.
nameexhaustion
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Oct 11, 2024
… in a fork()-without-execve() child (pola-rs#19149)" This reverts commit 48bc09b.
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This is an alternative implementation for #5342, which was reverted due to side-effects.
This implementation should not affect any non-Polars using code. It won't catch all cases of people using Polars in a fork()-without-execve() child, but it will catch many of them.