diff --git a/source/core/sharding-shard-key.txt b/source/core/sharding-shard-key.txt index 93ad081cd1a..6c45ee1b35f 100644 --- a/source/core/sharding-shard-key.txt +++ b/source/core/sharding-shard-key.txt @@ -141,11 +141,11 @@ performance. Query Isolation ``````````````` -The fastest queries in a sharded environment are those that +Generally, the fastest queries in a sharded environment are those that :program:`mongos` will route to a single shard, using the :term:`shard key` and the cluster meta data from the :ref:`config server `. For queries that don't include the shard -key, :program:`mongos` must query all shards, wait for their response +key, :program:`mongos` must query all shards, wait for their responses and then return the result to the application. These "scatter/gather" queries can be long running operations.