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  1. Core Server
  2. SERVER-17386

Cursor cache causes excessive memory utilization in WiredTiger

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Details

    • Bug
    • Status: Closed
    • Major - P3
    • Resolution: Fixed
    • 3.0.0-rc10
    • 3.0.5, 3.1.5
    • WiredTiger
    • Fully Compatible
    • ALL
    • Quint Iteration 3.1.2, Quint Iteration 3, Quint Iteration 5

    Description

      Issue Status as of Jul 14, 2015

      ISSUE SUMMARY
      WiredTiger allows MongoDB to open an unbounded number of WiredTiger sessions, which means that despite a limited number of WiredTiger cursors per session, the total number of cached sessions an cursors may lead to excessive memory use.

      USER IMPACT
      MongoDB with WiredTiger may consume too much memory in some situations, leading to excessive memory use beyond the normal WiredTiger database cache, potentially triggering out of memory conditions and even the OOM killer.

      WORKAROUNDS
      None.

      AFFECTED VERSIONS
      MongoDB 3.0.0 through 3.0.4.

      FIX VERSION
      The fix is included in the 3.0.5 production release.

      Original description

      Running RC10 with the c# driver, 50 threads concurrently bulk inserting/updating/reading, I see stacktraces in the console output followed by a big speed drop. The speed drop appears to be related to reads, but I can't be sure yet.

      I will attempt to reproduce this with a long running test and report back.

      Attachments

        1. mongo.png
          mongo.png
          143 kB
        2. mongoMem.png
          mongoMem.png
          47 kB

        Issue Links

          is duplicated by

          Bug - A problem which impairs or prevents the functions of the product. SERVER-17456 Mongodb 3.0 wiredTiger storage engine memory usage too high.

          • Critical - P2 - Crashes, loss of data, severe memory leak.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. SERVER-18821 64 sessions created in single threaded workload

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

          Bug - A problem which impairs or prevents the functions of the product. SERVER-19273 Short range scan using YCSB cause mongodb crash

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

          Bug - A problem which impairs or prevents the functions of the product. SERVER-19562 Restore error: insertion error with out-of-memory condition

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

          Bug - A problem which impairs or prevents the functions of the product. NODE-487 WiredTiger memory leak

          • Critical - P2 - Crashes, loss of data, severe memory leak.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. SERVER-17424 WiredTiger uses substantially more memory than accounted for by cache

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

          Bug - A problem which impairs or prevents the functions of the product. SERVER-17364 Idle cursors shouldn't hold storage engine resources

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

          Activity

            People

              michael.cahill@mongodb.com Michael Cahill (Inactive)
              nickj Nick Judson
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              35 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved: