Determine whether we need const CollectionShardingState/DatabaseShardingState instances for Lock-Free Reads

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    • Type: Task
    • Resolution: Done
    • Priority: Major - P3
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    • Affects Version/s: None
    • Component/s: Storage
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    • Execution Team 2020-12-28, Execution Team 2021-01-11, Execution Team 2021-01-25, Execution Team 2021-02-08, Execution Team 2021-02-22
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      Currently we're adding shared_ptr getters to the interfaces in SERVER-51319.

      Ideally, CSS::getShared, etc., would return const pointers, but would require further interface changes to accept const pointers. Also, without const pointers, or more accurately without copy-on-write, the metadata instance fetched can be modified during a read. (internally, Collection/DatabaseShardingState have concurrency control via mutex, but state still changes??)

      Maybe this is safe, but need to double check, particularly with things like the resharding project coming up?

            Assignee:
            Dianna Hohensee (Inactive)
            Reporter:
            Dianna Hohensee (Inactive)
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              Created:
              Updated:
              Resolved: