Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-1602

mongos crashes when multiple map reduce jobs run in parallel

    XMLWordPrintableJSON

Details

    • Icon: Bug Bug
    • Resolution: Done
    • Icon: Major - P3 Major - P3
    • 1.6.3, 1.7.1
    • 1.6.0
    • Sharding
    • None
    • ALL

    Description

      mongos process crashes if we run multiple map reduce jobs in parallel. It works properly if those jobs are ran serially.

      The issue is not intermittent. mongos will crash every time we try to execute the jobs in parallel.

      Our flow is:

      • Generate the selector/query A
      • Run 3 map reduce jobs with query A
      • Run a query with find().skip().limit().sort() with query A and sort by B
      • Run a count() query with query A

      we run these steps in parallel with 5 threads.

      Map reduce jobs are meant to generate a simple groupby/count resultset.

      map fn: function() {emit(this.FIELD,

      {count:1}

      );}; /* FIELD is: Make, Year, VehicleType for different jobs */
      reduce fn: function(key, vals) {var t = 0; for (var i = 0; i < vals.length; i++) t += vals[i].count; return

      {count:t}

      ;};

      Attachments

        1. 1.txt
          4 kB
        2. 2.txt
          6 kB
        3. MongoDB-SERVER-1602-Example.zip
          726 kB

        Activity

          People

            mathias@mongodb.com Mathias Stearn
            occ Onur Cakmak
            Votes:
            2 Vote for this issue
            Watchers:
            2 Start watching this issue

            Dates

              Created:
              Updated:
              Resolved: