Uploaded image for project: 'WiredTiger'
  1. WiredTiger
  2. WT-6490

Acquire snapshot for eviction threads

    XMLWordPrintable

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major - P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: WT10.0.0, 4.4.2, 4.9.0
    • Component/s: None
    • Labels:
      None
    • Story Points:
      5
    • Sprint:
      Storage - Ra 2020-09-07, Storage - Ra 2020-09-21, Storage - Ra 2020-10-19

      Description

      At the moment eviction threads use checks based on global visibility rules - which means that they don't evict anything that isn't globally visible (based on transaction ID checks, not timestamp checks).

      We should update eviction so that it can evict anything that is committed or prepared. A possible way to do that is to allocate a transaction snapshot when doing evictions, but that requires care because application threads might be doing the eviction and we need to be careful not to use or disrupt their snapshot.

      See WT-6444 for more context and a workload where this change is beneficial.

        Attachments

        1. Screen Shot 2020-08-18 at 4.32.35 pm.png
          Screen Shot 2020-08-18 at 4.32.35 pm.png
          832 kB
        2. Screen Shot 2020-08-18 at 4.33.54 pm.png
          Screen Shot 2020-08-18 at 4.33.54 pm.png
          879 kB
        3. FTDC_base.zip
          1.67 MB
        4. FTDC_eviction_improvement.zip
          1.81 MB
        5. a-1.png
          a-1.png
          122 kB
        6. a-2.png
          a-2.png
          119 kB
        7. a-3.png
          a-3.png
          119 kB
        8. image-2020-08-20-10-22-34-887.png
          image-2020-08-20-10-22-34-887.png
          382 kB
        9. image-2020-08-20-10-38-59-705.png
          image-2020-08-20-10-38-59-705.png
          338 kB
        10. image-2020-08-20-10-49-07-353.png
          image-2020-08-20-10-49-07-353.png
          221 kB
        11. eviction.patch
          77 kB

          Issue Links

            Activity

              People

              Assignee:
              haseeb.bokhari Haseeb Bokhari
              Reporter:
              alexander.gorrod Alexander Gorrod
              Votes:
              0 Vote for this issue
              Watchers:
              17 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved: