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  1. Core Server
  2. SERVER-89088

Time series queries do not use plan cache when query parameters are changed slightly

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    • Type: Icon: Task Task
    • Resolution: Unresolved
    • Priority: Icon: Major - P3 Major - P3
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    • Query Execution
    • 129

      A query like

      [
  {"$match":{
"measurement":"cpu", 
"tags.hostname":{"$in":["host_18"]}, // H = 1
	"time":{
"$gte": new Date("2016-01-13T21:49:27.243Z"), // T = 1h
"$lt": new Date("2016-01-13T22:49:27.243Z")}, 
  }},
  {"$group":{
"_id":{"$dateTrunc":{"date":"$time","unit":"minute"}},
	"max_usage_user":{"$max":"$usage_user"} // M = 1
  }},
  {"$sort":{"_id":1}}
]

      will use the plan cache when the same query is executed over and over. However, if you slightly adjust the parameters in the $match, it will not. This means that in practice most TS queries will have to multi-plan again each time.

      CC parker.felix@mongodb.com who discovered the bug.

            Assignee:
            ian.boros@mongodb.com Ian Boros
            Reporter:
            ian.boros@mongodb.com Ian Boros
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              Created:
              Updated: