Switch timezone singletons and caches with weak references #635
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I'd be interested in working on this. |
gokcennurlu
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Jun 14, 2018
Caching had been switched to use `weakrefs` in order to reuse instances if they are still alive, by dateutil#635. This introduces a LRU cache to the mentioned functions in order to prevent the instances created by them getting dealloc'd and alloc'd unnecessarily, in situations like this: ```python for i in range(100): tz.gettz('America/New_York') ``` `tz.tzoffset` and `tz.tzstr` get a LRU cache with size of 8. `tz.gettz`'s cache starts with 8 by default and can be modified by the introduced `tz.set_cache_size(int)` Closes dateutil#691
pganssle
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Sep 24, 2018
Caching had been switched to use `weakrefs` in order to reuse instances if they are still alive, by dateutil#635. This introduces a LRU cache to the mentioned functions in order to prevent the instances created by them getting dealloc'd and alloc'd unnecessarily, in situations like this: ```python for i in range(100): tz.gettz('America/New_York') ``` `tz.tzoffset` and `tz.tzstr` get a LRU cache with size of 8. `tz.gettz`'s cache starts with 8 by default and can be modified by the introduced `tz.set_cache_size(int)` Closes dateutil#691
pganssle
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Oct 16, 2018
Caching had been switched to use `weakrefs` in order to reuse instances if they are still alive, by dateutil#635. This introduces a LRU cache to the mentioned functions in order to prevent the instances created by them getting dealloc'd and alloc'd unnecessarily, in situations like this: ```python for i in range(100): tz.gettz('America/New_York') ``` `tz.tzoffset` and `tz.tzstr` get a LRU cache with size of 8. `tz.gettz`'s cache starts with 8 by default and can be modified by the introduced `tz.set_cache_size(int)` Closes dateutil#691
pganssle
added a commit
to gokcennurlu/dateutil
that referenced
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Oct 16, 2018
Caching had been switched to use `weakrefs` in order to reuse instances if they are still alive, by dateutil#635. This introduces a LRU cache to the mentioned functions in order to prevent the instances created by them getting dealloc'd and alloc'd unnecessarily, in situations like this: ```python for i in range(100): tz.gettz('America/New_York') ``` `tz.tzoffset` and `tz.tzstr` get a LRU cache with size of 8. `tz.gettz`'s cache starts with 8 by default and can be modified by the introduced `tz.set_cache_size(int)` Closes dateutil#691
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Right now
tzoffset,tzstrandtz.gettzeach retain strong references to every unique time zone ever constructed by that method. I think in the end this will be a net savings in memory in most use cases since it prevents duplication of time zones, but it could also cause a huge proliferation of memory in applications that make short-lived references to a large number of time zones (since those time zones, when they go out of scope, would normally get garbage collected).In Python 3 there is the weakref module, which allows the creation of weak references, such that an object will be garbage collected if only weak references to it exist.
Rather than try and use
backports.weakrefin Python 2, I think we can just write a "pass through" compatibility shim that has the same external form asweakrefbut simply holds a strong reference to the object in question.The text was updated successfully, but these errors were encountered: