Details
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New Feature
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Status: Resolved
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Minor
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Resolution: Fixed
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None
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None
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None
Description
The `stale` mechanism for view queries conflates two independent
concerns:
1. Whether or not the view results should be returned from a "stable"
set of shards; i.e., mem3:ushards. This semantic is new in 2.0,
having originated in Cloudant code in 2011[1].
2. Whether or not the view in question should be updated prior to
responding to the user, i.e., the pre-2.0 semantics.
Both of these concerns represent consistency/availability tradeoffs, but
they're addressing rather different aspects of that continuum. As such,
the "stale" mechanism limits flexibility.
For example, it's quite likely that a user would want to retrieve
"stale" view responses from the fastest available shards - the
"available/available" choice - and this choice is not available with the
existing "stale" mechanism. A similar argument could be made for the
"consistent/consistent" choice.
[1]: https://github.com/apache/couchdb-fabric/commit/93923fda51c714c015b8621e41f3c425bfb3e61a
