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  1. Core Server
  2. SERVER-79805

Explain command does not report executionStats for the merger part of a split pipeline

    • Query Execution

      I've noticed that for sharded collections, we report executionStats under the shards field for each sub-pipeline that gets executed on the individual shards. But we don't have any information about what is happening on mongos during the $mergeCursors or the stages after the $mergeCursors. For example, a $group or a $sort could spend a significant amount of time after the $mergeCursors and we provide no information about that in the explain. There could also be a network latency between the mongos and mongod communication that would be easy to identify if we report executionStats on mongos.

            Assignee:
            backlog-query-execution [DO NOT USE] Backlog - Query Execution
            Reporter:
            arun.banala@mongodb.com Arun Banala
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              Created:
              Updated: