wehub-resource-sync
39 lines
1.6 KiB
ReStructuredText
39 lines
1.6 KiB
ReStructuredText
Anti-pattern: Closure capturing large objects harms performance
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===============================================================
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**TLDR:** Avoid closure capturing large objects in remote functions or classes, use object store instead.
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When you define a :func:`ray.remote <ray.remote>` function or class,
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it is easy to accidentally capture large (more than a few MB) objects implicitly in the definition.
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This can lead to slow performance or even OOM since Ray is not designed to handle serialized functions or classes that are very large.
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For such large objects, there are two options to resolve this problem:
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- Use :func:`ray.put() <ray.put>` to put the large objects in the Ray object store, and then pass object references as arguments to the remote functions or classes (*"better approach #1"* below)
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- Create the large objects inside the remote functions or classes by passing a lambda method (*"better approach #2"*). This is also the only option for using unserializable objects.
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Code example
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------------
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**Anti-pattern:**
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.. literalinclude:: ../doc_code/anti_pattern_closure_capture_large_objects.py
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:language: python
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:start-after: __anti_pattern_start__
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:end-before: __anti_pattern_end__
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**Better approach #1:**
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.. literalinclude:: ../doc_code/anti_pattern_closure_capture_large_objects.py
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:language: python
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:start-after: __better_approach_1_start__
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:end-before: __better_approach_1_end__
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**Better approach #2:**
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.. literalinclude:: ../doc_code/anti_pattern_closure_capture_large_objects.py
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:language: python
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:start-after: __better_approach_2_start__
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:end-before: __better_approach_2_end__
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