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  1. Core Server
  2. SERVER-13100

Large $in queries are several orders of magnitude slower

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Details

    • Bug
    • Status: Closed
    • Blocker - P1
    • Resolution: Fixed
    • 2.6.0-rc1
    • 2.6.0-rc2
    • Querying
    • ALL
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      build/run attached cpp file.

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      build/run attached cpp file.

    Description

      Running the attached client as follows:

      ben@zzyzx:~/projects/mongo-utils/build$ ./in_query localhost:27249 100000
      		 
      Total query time in miliseconds: 389
      		 
      Doc count: 100000
      		 
      ben@zzyzx:~/projects/mongo-utils/build$ ./in_query localhost:27261 10000
      		 
      Total query time in miliseconds: 2103
      		 
      ben@zzyzx:~/projects/mongo-utils/build$ ./in_query localhost:27261 100000
      		 
      Total query time in miliseconds: 380121
      		 
      Doc count: 100000

      The last execution never returns a result, and the client is blocked in the call to DBClientCursor::more(). Note that the server logs the slow query at ~230ms on my machine, but the process continues to consume 100% cpu for 380 seconds.

      Attachments

        1. in_query_100_unindexed.svg
          117 kB
        2. in_query.cpp
          2 kB
        3. in_query.pdf
          8 kB
        4. in_query.svg
          42 kB
        5. server13100.js
          0.8 kB

        Issue Links

          is related to

          Improvement - An improvement or enhancement to an existing feature or task. SERVER-1211 don't use simplifiedQuery() to negate earlier index ranges in new matcher

          • Major - P3 - Major loss of function.
          • Closed
          related to

          Bug - A problem which impairs or prevents the functions of the product. SERVER-13139 Performance regression with smaller $in queries

          • Major - P3 - Major loss of function.
          • Closed

          Activity

            People

              benety.goh@mongodb.com Benety Goh
              benjamin.becker Ben Becker
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              Dates

                Created:
                Updated:
                Resolved: