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Created on 2021-10-08 23:52 by olliemath, last changed 2022-04-11 14:59 by admin.
| Files | ||||
|---|---|---|---|---|
| File name | Uploaded | Description | Edit | |
| huge.py | olliemath, 2021-10-08 23:52 | A single very large enum | ||
| quadratic-fix-2.diff | mattip, 2021-10-10 14:56 | |||
| Pull Requests | |||
|---|---|---|---|
| URL | Status | Linked | Edit |
| PR 28907 | merged | Carl.Friedrich.Bolz, 2021-10-12 18:47 | |
| Messages (5) | |||
|---|---|---|---|
| msg403512 - (view) | Author: Oliver Margetts (olliemath) | Date: 2021-10-08 23:52 | |
Creating large enums takes a significant amount of time. Moreover this appears to be nonlinear in the number of entries in the enum. Locally, importing a single python file and taking this to the extreme: 1000 entries - 0.058s 10000 entries - 4.327s This is partially addressed by https://bugs.python.org/issue38659 and I can confirm that using `@_simple_enum` does not have this problem. But it seems like that API is only intended for internal use and the 'happy path' for user-defined enums is still not good. Note that it is not simply parsing the file / creating the instances, it is to do with the cardinality. Creating 100 enums with 100 entries each is far faster than a single 10000 entry enum. |
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| msg403585 - (view) | Author: Armin Rigo (arigo) *  |
Date: 2021-10-10 13:12 | |
The timing is clearly quadratic: number of attributes time 1500 0.24s 3000 0.94s 6000 3.74s 12000 15.57s Pressing Ctrl-C in the middle of the execution of the largest examples points directly to the cause: when we consider the next attribute, we loop over all previous ones at enum.py:238. |
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| msg403592 - (view) | Author: mattip (mattip) * | Date: 2021-10-10 14:56 | |
Over at PyPy arigo authored and we applied this fix to the as-yet unreleased pypy3.8. Note that it cannot be applied directly to CPython as sets are not ordered. Does the fix break anything? Tests in Lib/test/test_enum.py passed after applying it. |
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| msg403751 - (view) | Author: Carl Friedrich Bolz-Tereick (Carl.Friedrich.Bolz) * | Date: 2021-10-12 18:48 | |
I fixed the reliance of set being insertion ordered in pypy and opened a pull request. |
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| msg403947 - (view) | Author: Ethan Furman (ethan.furman) * |
Date: 2021-10-14 20:59 | |
New changeset b2af211e229df941d9b404f69547a264115156b5 by Carl Friedrich Bolz-Tereick in branch 'main': bpo-45417: [Enum] fix quadratic behavior during creation (GH-28907) https://github.com/python/cpython/commit/b2af211e229df941d9b404f69547a264115156b5 |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:59:51 | admin | set | github: 89580 |
| 2021-10-15 16:07:46 | ethan.furman | set | assignee: ethan.furman stage: patch review -> backport needed versions: - Python 3.9 |
| 2021-10-14 20:59:55 | ethan.furman | set | messages: + msg403947 |
| 2021-10-12 18:48:35 | Carl.Friedrich.Bolz | set | messages: + msg403751 |
| 2021-10-12 18:47:05 | Carl.Friedrich.Bolz | set | nosy:
+ Carl.Friedrich.Bolz pull_requests: + pull_request27198 stage: patch review |
| 2021-10-10 15:57:11 | kj | set | nosy:
+ barry, eli.bendersky, ethan.furman versions: + Python 3.9, - Python 3.7 |
| 2021-10-10 14:56:55 | mattip | set | files:
+ quadratic-fix-2.diff nosy: + mattip messages: + msg403592 keywords: + patch |
| 2021-10-10 13:12:47 | arigo | set | nosy:
+ arigo messages: + msg403585 |
| 2021-10-08 23:52:33 | olliemath | create | |