The count command does not ignore orphans like find/queries. This is true whether the query is on the primary or secondaries (which is known to be a different issue).
For a query like this the count can come back larger if there are orphaned docs, but find will filter them out:
// more than one shard has the document with x:10, some of which are orphans from migrations > coll.count({x:10}) 2 > coll.find({x:10}).toArray() [{_id:10, x:10}] > coll.find({x:10}).explain() // some of the explain is removed for brevity { "clusteredType" : "ParallelSort", "shards" : { ... }, "n" : 1, "nChunkSkips" : 1, "numQueries" : 2, "numShards" : 2, "millis" : 2 }
- duplicates
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SERVER-5931 Secondary reads in sharded clusters need stronger consistency
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- Closed
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- related to
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SERVER-3645 Sharded collection counts (on primary) can report too many results
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- Closed
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