Uploaded image for project: 'Core Server'
  1. Core Server
  2. SERVER-20248

Memory growth in __wt_session_get_btree in __checkpoint_worker under WiredTiger

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 3.0.6
    • Component/s: WiredTiger
    • Labels:
    • Backwards Compatibility:
      Fully Compatible
    • Operating System:
      ALL

      Description

      This is ticket is related to the latest issue discussed on SERVER-17456. The key features of the test involve:

      • relatively large number of collections (16k)
      • 16 threads each looping through 1k of the 16k collections writing a record and doing a createIndex (on an existing index, not a new index).

      Memory outside WT cache is observed to steadily grow over a period of hours in a test on 3.0.5:

      • allocated memory outside of WT cache (3rd line) grows steadily.
      • there is a sudden increase corresponding to the known issue with WT journal allocation in 3.0.5.
      • aside from that sudden jump the growth in non-cache memory is linear over time.
      • number of cached cursors is also growing and that is a known potential user of memory, but the shape of the growth curve for number of cursors does not match the linear shape of the growth of non-cached memory.

      Memory profiling using tcmalloc HEAPPROFILE shows the following as a candidate for the culprit: various allocations within in __checkpoint_worker (labeled "A" below) steadily grow, and account for about 1.5 GB of non-cache memory by the end of this run:

        Attachments

        1. close_idle_time=300.png
          54 kB
          Bruce Lucas
        2. heap.png
          313 kB
          Bruce Lucas
        3. heap2.png
          160 kB
          Bruce Lucas
        4. mem.png
          132 kB
          Bruce Lucas
        5. ss.png
          81 kB
          Bruce Lucas

          Issue Links

            Activity

              People

              • Votes:
                0 Vote for this issue
                Watchers:
                9 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved: